Criminal Law & Procedure

An ordinance, and eight people arrested under it

Jacksonville, Florida, 1972. The city's vagrancy ordinance, copied almost word for word from English statutes hundreds of years old, made it a crime to be a rogue, a vagabond, a common night walker, a habitual loafer, a person using juggling, or a person wandering or strolling around from place to place without any lawful purpose or object. Margaret Papachristou and Betty Calloway, both white, were riding in a car with Eugene Melton and Leonard Johnson, both Black, on a main street in Jacksonville. They were on their way to a nightclub. Police stopped the car and booked all four for prowling by auto.

The Supreme Court threw the ordinance out unanimously in Papachristou v. City of Jacksonville, 405 U.S. 156 (1972). Justice Douglas did not say the city lacked power to punish loitering. He said this law was not usable as law. It failed to give an ordinary person notice of what was forbidden, and it handed police a blank warrant to arrest whoever displeased them, which is precisely what four people driving to a nightclub in a racially mixed car found out.

That single case contains the two questions this lesson answers. Where does a criminal prohibition come from, and what must it look like before a court will let the state enforce it? Get those right and the rest of the course has a floor to stand on.

One boundary before we start. This is general education about how United States criminal law works. It is not legal advice, it does not create a lawyer-client relationship, and no lesson here can substitute for a licensed attorney in your jurisdiction, because the answer to almost every real question begins with which state you are in.

Four sources, in the order they matter

American criminal law arrives from several directions at once, and knowing which source governs is often half the analysis.

Statutes come first. Today essentially every crime you can be convicted of is defined by a legislature in writing. Each state has a penal code; Congress has Title 18 of the United States Code and hundreds of criminal provisions scattered through other titles. This was not always so. English and early American courts recognised common law crimes, offences judges declared and defined themselves. Federal courts lost that authority early: in United States v. Hudson and Goodwin, 11 U.S. 32 (1812), the Supreme Court held that federal courts have no common law criminal jurisdiction, so there is no federal crime unless Congress wrote one. Most states abolished common law crimes by statute during the twentieth century, though a handful retain them in residual form.

The common law is still everywhere anyway. Abolishing common law crimes did not abolish common law meaning. When a statute says murder and does not define malice aforethought, courts reach for centuries of decisions that do. Terms like burglary, larceny, and assault come to modern codes pre-loaded with old content. You will meet this again and again: a two-line statute resting on two hundred years of case law.

The Model Penal Code is the most influential text nobody enacted. The American Law Institute, a private body of judges, lawyers, and academics, spent from 1952 to 1962 drafting a model criminal code. No jurisdiction is bound by it, because the ALI cannot legislate. Yet more than thirty states rewrote their criminal codes in the decades after 1962 and borrowed heavily from it, and courts everywhere cite it when a statute is ambiguous. Its greatest contribution, the four culpable mental states, is the subject of a lesson of its own.

Constitutions set ceilings, not floors. The federal Constitution never creates a crime. It limits what legislatures may criminalise and how the state may prove a case. State constitutions do the same and sometimes go further, protecting more than the federal minimum. The site's Constitutional Law course, LAW 310, works the constitutional doctrines themselves; here we take them as constraints on criminal law and procedure.

Two smaller sources round out the list. Administrative regulations can carry criminal penalties when a statute authorises them, which is how environmental and food safety violations become prosecutable. And municipal ordinances, like the Jacksonville one, create local offences enforceable by local police.

The point: Crimes are defined by statute, interpreted through inherited common law meanings, shaped by the Model Penal Code, and bounded by constitutions.

Federal or state, and why it usually does not matter

Students often assume criminal law is federal. It overwhelmingly is not. States hold the general police power, meaning the authority to legislate for health, safety, welfare, and morals, and roughly nine in ten criminal prosecutions in the United States are brought under state law. Congress has no general police power; every federal crime must be tied to an enumerated power, most often the commerce power, the taxing power, or federal property and personnel.

The practical consequence is that murder, robbery, burglary, and assault are prosecuted in state courts by county district attorneys, while federal prosecutors concentrate on offences with an interstate or federal hook: drug trafficking networks, immigration, firearms, fraud that crosses state lines, public corruption, and crimes on federal land. Some conduct violates both, and prosecution by both sovereigns does not violate double jeopardy under the dual sovereignty doctrine, which the Court reaffirmed in Gamble v. United States, 587 U.S. 678 (2019). The system's institutions, from police departments to corrections, are surveyed in the site's Introduction to Criminal Justice course, CRIJ 1301; this course stays on the law.

The legality principle

Here is the oldest idea in criminal law, usually given in Latin: nullum crimen sine lege, nulla poena sine lege. No crime without law, no punishment without law. Strip the Latin and it says something demanding. The state may punish you only for conduct that a written rule, in force before you acted, clearly forbade.

Four corollaries follow, and each one is enforceable in court.

1. Crimes must be defined in advance and in writing. A judge may not invent an offence to punish conduct everyone agrees is wicked.
2. Criminal statutes may not operate retroactively. This is the ex post facto ban.
3. Criminal statutes must be reasonably clear. This is the void for vagueness doctrine that killed the Jacksonville ordinance.
4. Ambiguity is resolved in favour of the defendant. This is the rule of lenity.

The principle is not squeamishness about punishing bad people. It is a rule about power. A vague or retroactive criminal law gives officials discretion to select their targets after the fact, and selection after the fact is how criminal law becomes a tool against disfavoured people rather than against dangerous conduct.

Why this matters: Legality converts punishment from an exercise of official will into the application of a rule that existed before the defendant acted.

Vagueness: the test and two modern examples

A criminal statute is void for vagueness under the Due Process Clause if it fails either of two tests: it does not give a person of ordinary intelligence fair notice of what is prohibited, or it invites arbitrary and discriminatory enforcement. Courts care more about the second prong than students expect. Notice matters, but the deeper worry is a law so open that the officer on the street, not the legislature, decides what the crime is.

In City of Chicago v. Morales, 527 U.S. 41 (1999), Chicago made it an offence to remain in a public place with no apparent purpose after an officer, believing at least one person present was a gang member, ordered the group to disperse. Police issued tens of thousands of dispersal orders and made thousands of arrests. The Court struck the ordinance down: no apparent purpose gave citizens no way to know what was forbidden and gave officers absolute discretion.

Vagueness also reaches sentencing statutes. In Johnson v. United States, 576 U.S. 591 (2015), the Court held that the residual clause of the Armed Career Criminal Act, which raised sentences for prior felonies involving conduct that presents a serious potential risk of physical injury to another, was unconstitutionally vague. The clause had produced years of irreconcilable decisions about which crimes qualified, which was itself evidence that no one could tell.

Compare a statute that survives. A law forbidding driving with a blood alcohol concentration of 0.08 percent or more is unambiguous at the edges as well as the centre. That is the target: a rule you could obey deliberately.

Remember: Vagueness is measured by notice and by the discretion the statute hands to enforcers, and the second failure is usually the fatal one.

Ex post facto and retroactive judicial expansion

Article I forbids both Congress and the states to pass any ex post facto law. In Calder v. Bull, 3 U.S. 386 (1798), Justice Chase gave the four categories still used today. A law is ex post facto if it (1) criminalises conduct that was innocent when done, (2) aggravates a crime after the fact, (3) increases the punishment for a crime after it was committed, or (4) alters the rules of evidence to make conviction easier on less testimony than the law required when the act was done.

Note what the clause does not cover. It restrains legislatures, not courts. So what stops a court from reading an old statute in a new and broader way to reach a defendant who could not have anticipated it? The Due Process Clause does. In Bouie v. City of Columbia, 378 U.S. 347 (1964), South Carolina's courts expanded a trespass statute that punished entry after notice so that it also covered remaining after being asked to leave, and applied that reading to civil rights sit-in demonstrators. The Supreme Court reversed: an unforeseeable judicial enlargement of a criminal statute, applied retroactively, does the same work as an ex post facto law and is equally forbidden. The doctrine has been narrowed since, notably in Rogers v. Tennessee, 532 U.S. 451 (2001), where a divided Court allowed abolition of the old year and a day rule in homicide to apply to the defendant before it, and the line between routine common law development and forbidden expansion remains genuinely contested.

Lenity, and why an airplane was not a motor vehicle

When a criminal statute is genuinely ambiguous after a court has exhausted the ordinary tools of interpretation, the rule of lenity resolves the ambiguity in the defendant's favour. It is a tiebreaker, not a thumb on the scale, and courts reach it last.

The classic illustration is McBoyle v. United States, 283 U.S. 25 (1931). McBoyle was convicted of transporting a stolen aircraft across state lines under the National Motor Vehicle Theft Act, which defined a motor vehicle to include an automobile, automobile truck, automobile wagon, motorcycle, or any other self-propelled vehicle not designed for running on rails. An airplane is self-propelled and does not run on rails. Justice Holmes still reversed. In everyday speech a motor vehicle runs on land, and, he wrote, a fair warning should be given to the world in language that the common world will understand. Congress could easily have said aircraft. It had not, so McBoyle went free and Congress amended the statute the next year.

Notice how tidy the division of labour is. Lenity does not say airplane theft should be lawful. It says that if the legislature wants to punish it, the legislature must say so.

Bottom line: Vagueness, ex post facto, and lenity are three enforcement mechanisms for one idea: the rule must exist, and be findable, before the conduct.

Criminal, civil, and the burden between them

The same punch can produce two cases. In the criminal case the state prosecutes for battery, the standard of proof is beyond a reasonable doubt, and the sanction is a fine, probation, or incarceration plus a conviction record. In the civil case the injured person sues for the tort of battery, the standard is a preponderance of the evidence, and the remedy is money. The two are independent, which is why an acquittal does not bar a later civil suit.

The heavy criminal burden is constitutional, not merely traditional. In re Winship, 397 U.S. 358 (1970), held that due process requires proof beyond a reasonable doubt of every fact necessary to constitute the crime charged. The reason is asymmetry of error: a system that convicts the innocent inflicts a harm the state cannot undo, so it accepts that some guilty people will walk.

Offences are also graded by seriousness. A felony is typically punishable by more than a year of imprisonment, a misdemeanour by up to a year in a local jail, and an infraction or violation by fine alone. That line drives everything downstream: which court hears the case, whether a grand jury is involved, whether counsel must be appointed, and what collateral consequences follow a conviction.

Common misconceptions

• Judges can create crimes when conduct is clearly harmful. Federal courts never could after 1812, and nearly all states abolished common law crimes; a legislature must act first.
• A vague law is fine as long as the defendant clearly knew it was wrong. Vagueness is judged by the statute's notice and by the discretion it gives enforcers, not by whether this defendant felt guilty.
• The rule of lenity means close cases go to the defence. Lenity applies only after the ordinary interpretive tools leave a genuine ambiguity, which is rarer than defence briefs suggest.
• The Model Penal Code is the law. It is a model drafted by a private organisation; it governs only where a legislature enacted it, though its influence is enormous.
• Being acquitted means the conduct never happened. An acquittal means the state failed to prove guilt beyond a reasonable doubt; a civil jury may still find the same conduct more likely than not.

Where this leaves us

• Criminal prohibitions come from statutes, read against inherited common law meanings, influenced by the Model Penal Code and bounded by constitutions.
• States hold the general police power and bring the large majority of prosecutions; federal crimes need an enumerated hook.
• The legality principle requires rules that are written, prospective, clear, and strictly construed.
• Papachristou, Morales, and Johnson show vagueness doctrine at work, and its sharpest concern is enforcement discretion.
• Calder sets the four ex post facto categories; Bouie extends the idea to unforeseeable judicial expansion.
• McBoyle shows lenity: if the legislature wants to punish it, the legislature must say so.
• Criminal cases are brought by the state and require proof beyond a reasonable doubt, a rule Winship made constitutional.

Sources

1. Legal Information Institute. (n.d.). Criminal law. Cornell Law School. law.cornell.edu
2. Legal Information Institute. (n.d.). Void for vagueness. Cornell Law School. law.cornell.edu
3. Britannica. (2024). Criminal law. britannica.com
4. Wikipedia. (n.d.). Papachristou v. City of Jacksonville. en.wikipedia.org
5. Congressional Research Service. (n.d.). Constitution Annotated: Article I, ex post facto clauses. constitution.congress.gov

A man carried onto a highway

Alabama, 1944. Officers came to Martin's home, arrested him there, and took him out onto a public highway. On the highway he did what drunk men do: he shouted, he swore, he staggered. He was then convicted of being drunk on a public highway and manifesting a drunken condition by loud and profane language.

Every element of the offence was literally satisfied. He was drunk. He was on a public highway. He was loud. The Alabama Court of Appeals reversed the conviction anyway, in Martin v. State (Ala. Ct. App. 1944), with a sentence that is now in every criminal law casebook: the statute presupposes a voluntary appearance. Martin did not appear on the highway. He was carried there by the state that then prosecuted him for being there.

Start from the wrong answer and you learn more than from the right one. The wrong answer is that a crime is a list of elements and the prosecution wins by ticking them off. What Martin exposes is a requirement that hides underneath the list: before any element matters, there must be conduct that was the defendant's own. That requirement is the actus reus, and this lesson takes it apart.

What actus reus actually includes

Actus reus is usually translated as the guilty act, which is a bad translation because it smuggles in blame that belongs to the mental element. A better working definition: the actus reus of an offence is the voluntary act (or a qualifying omission) plus any result the offence requires and any attendant circumstances that must be present.

Take burglary of a dwelling at night. The act is breaking and entering. The attendant circumstances are that the structure is a dwelling, that it belongs to another, and that it is night. There is no required result at all: the burglar who finds the house empty and takes nothing has still completed the offence. Now take homicide. The act might be pulling a trigger; the required result is the death of a human being; the attendant circumstance is that the victim was alive when the defendant acted. Sorting a statute into these three buckets is not busywork. In the next lesson you will see that the required mental state can differ from bucket to bucket within a single crime.

The core of it: Actus reus is conduct plus results plus circumstances, and the conduct component must be voluntary.

What makes an act voluntary

Voluntary here does not mean freely chosen in any philosophical sense. A person who hands over a wallet at gunpoint acts voluntarily in the criminal law's sense; his defence is duress, which comes later. The law's meaning is narrow and physical. Model Penal Code section 2.01 says a person is not guilty unless liability is based on conduct that includes a voluntary act or an omission he was physically capable of performing, and it then lists what does not count:

• a reflex or convulsion;
• a bodily movement during unconsciousness or sleep;
• conduct during hypnosis or resulting from hypnotic suggestion;
• any bodily movement that is not a product of the effort or determination of the actor, either conscious or habitual.

Notice the word habitual. Driving home on autopilot and shifting gears without thinking is still voluntary. The test is not whether you deliberated, but whether the movement came from you.

Two illustrations mark the boundary. A driver has a heart attack and his car kills a pedestrian: the movement of the car after the attack was not his act, and he is not guilty of a homicide based on that movement. Now change the facts. In People v. Decina (N.Y. 1956), the defendant knew he was subject to epileptic seizures and drove anyway; a seizure caused a crash that killed four children. He was properly convicted, and the reasoning shows a move you will use constantly: the court simply widened the time frame. The seizure was not voluntary, but getting behind the wheel while knowing about the seizures was, and the state charged that act instead.

The same time-framing move decides the sleepwalking cases, which are real and rare. In 1987 a Toronto man named Kenneth Parks drove roughly fourteen miles while apparently asleep, killed his mother-in-law, and then presented himself at a police station saying he thought he had killed someone. Sleep experts testified for the defence; a jury acquitted him, and the Supreme Court of Canada upheld the acquittal in 1992. Cases like that make people uneasy, and they should be scrutinised hard, because the claim is unfalsifiable in the wrong hands. But the principle behind them is not soft: the criminal law punishes people for what they do, and a body moving during sleep is not doing.

So what?: When the harmful movement was involuntary, look earlier for a voluntary act that created the risk, and charge that.

Thoughts are not crimes, and neither is who you are

You cannot be punished for wanting someone dead. The line is drawn at conduct for two reasons: proof, because a system that punished intentions would need evidence it cannot honestly obtain, and liberty, because a person who forms a plan and abandons it has harmed no one. This is why attempt, which we cover later, requires an overt act and not merely a resolved mind.

Status is the harder case. In Robinson v. California, 370 U.S. 660 (1962), California made it a misdemeanour to be addicted to the use of narcotics, carrying a minimum of ninety days in jail. The statute did not require proof that the defendant had used, possessed, or bought anything in California. The Supreme Court held it violated the Eighth Amendment: a state may punish the acts of using or selling drugs, but it may not make the illness itself the offence. Punishing a person for a condition, Justice Stewart reasoned, is like making it a crime to be mentally ill or to have a common cold.

Six years later the Court declined to extend that. Powell v. Texas, 392 U.S. 514 (1968), involved Leroy Powell, convicted of being found in a state of intoxication in a public place. He argued he was a chronic alcoholic and could not stop himself. A divided Court affirmed the conviction. The plurality drew the distinction the doctrine has run on ever since: Texas punished Powell for appearing drunk in public, an act, not for the status of being an alcoholic.

That distinction thins out under pressure, as anyone who has read the dissents can see, and the pressure is currently on homelessness. Lower courts had read Robinson to bar punishing people for sleeping outside when no shelter beds existed, on the theory that sleeping is unavoidable and the defendant's only real offence was being unhoused. In City of Grants Pass v. Johnson (2024) the Supreme Court rejected that reading, holding that generally applicable public camping ordinances regulate conduct rather than status and so do not violate the Cruel and Unusual Punishments Clause. Whether you find that persuasive depends on how firmly you think the act and status line can hold when the act is one no human being can decline to perform. The doctrine is settled for now; the argument is not.

Possession, which is a state of affairs the law calls an act

Possession offences are everywhere: drugs, firearms, stolen property, contraband. Possession looks like a status rather than an act, which is why the Model Penal Code takes the trouble to define it in. Under section 2.01(4), possession is an act if the possessor knowingly procured or received the thing, or was aware of his control of it for a period long enough to have been able to terminate the possession.

That second clause matters. Someone slips a package into your coat pocket on a bus; you discover it two stops later and get off. You did not knowingly receive it, and you have not had a realistic chance to end the possession. If instead you carry it home, look at it, and put it in a drawer, you possess it.

Two further terms travel with possession. Actual possession means the item is on your person. Constructive possession means you have the power and the intention to control it, even at a distance: drugs in your locked glove compartment, a gun in your bedroom closet. Constructive possession does real work in prosecutions and also produces real injustice, because in a car with four occupants and a pistol under a seat, the theory can reach everyone in the car. Courts respond by requiring more than mere presence or proximity, but juries are asked to draw the line on thin facts.

Omissions: when doing nothing is the actus reus

The general rule in American criminal law is blunt and often surprises students. There is no legal duty to rescue. A strong swimmer can stand on a dock, watch a stranger's child drown in three feet of water, do nothing, and commit no crime, however contemptible we find him. Most European systems disagree and impose a general duty of easy rescue; a handful of American states, including Vermont and Minnesota, have enacted narrow duty-to-assist statutes, usually with small penalties.

The common law instead recognises specific duties. The standard list, drawn from Jones v. United States (D.C. Cir. 1962) and expanded by later courts, has five sources:

1. Statute. Tax filing, accident reporting, mandated child abuse reporting.
2. Status relationship. Parent to child, spouse to spouse; sometimes an employer to an employee in peril.
3. Contract. A nurse, lifeguard, or paid caregiver has undertaken the duty by agreement. In Commonwealth v. Pestinikas (Pa. Super. Ct. 1992), a couple who contracted to feed and care for an elderly man, then withheld food until he died, were convicted of murder on exactly this theory.
4. Voluntary assumption of care that isolates the victim. If you begin a rescue and thereby stop others from helping, you may not abandon it.
5. Creation of the peril. If you push someone into a river, even accidentally, you have a duty to try to get them out.

The narrowness is illustrated by People v. Beardsley (Mich. 1907). Beardsley spent a weekend drinking with a woman who was not his wife; she took morphine in his presence and he had her moved to a neighbour's basement, where she died. The court found no duty, because she was not his spouse and he had assumed no care. It is a repellent result that states the rule accurately.

A cultural note worth correcting while we are here. The 1964 killing of Kitty Genovese in Queens is often taught as proof that thirty-eight witnesses watched and did nothing. Later investigation established that the original newspaper account was substantially wrong: far fewer people saw any part of the attack, several did call police, and a neighbour came to her aid. The bystander effect is a genuine finding in psychology; the Genovese story as usually told is not the evidence for it.

In short: Omission liability requires a legal duty from statute, status, contract, assumption, or creation of the peril, plus the physical ability to act.

The act and omission line, tested at a bedside

Now a case that will not resolve itself with intuition. In Barber v. Superior Court (Cal. Ct. App. 1983), physicians disconnected a comatose patient's ventilator and later his intravenous feeding, at the family's request, and prosecutors charged them with murder. Turning a dial and pulling a tube certainly look like acts. The court held otherwise: withdrawing life support is properly analysed as the cessation of treatment, an omission, and because a physician has no duty to continue treatment that has become futile, there was no unlawful failure to act and therefore no actus reus.

Sit with the reasoning rather than the result. It is not that the doctors did nothing; they moved their hands. It is that the law asked whether they breached a duty to continue, and found none. That reframing shows what the act and omission distinction really is: not a description of physical motion, but a question about which duty the state says you broke.

Common misconceptions

• Any bodily movement is a voluntary act. Reflexes, convulsions, movement during sleep or unconsciousness, and hypnotic conduct are excluded, though a court may find an earlier voluntary act that created the risk.
• Acting under threat is involuntary. Handing over money at gunpoint is a voluntary act; the answer is the duress defence, not the absence of actus reus.
• You can be prosecuted for a plan you never acted on. Criminal law requires conduct; attempt and conspiracy each demand an overt step beyond the thought.
• Anyone who watches a stranger die commits a crime. American law imposes no general duty to rescue; liability requires one of the recognised duty sources.
• Possession is not an act, so possession crimes are unconstitutional. Codes define possession as an act where the person knowingly received the item or had time to end the possession.
• Robinson means addiction is a complete defence. Robinson bars punishing the status itself; Powell allows punishing acts such as public intoxication even when they flow from addiction.

The short version

• Actus reus is a voluntary act or qualifying omission, plus any required result and attendant circumstances.
• Martin shows that literal element satisfaction is not enough when the state supplied the conduct.
• The Model Penal Code excludes reflexes, convulsions, sleep, unconsciousness, and hypnosis; habitual movements still count.
• Decina and the sleepwalking cases turn on time framing: look for an earlier voluntary act.
• Thoughts and status cannot be crimes; Robinson, Powell, and Grants Pass mark a line that is still argued over.
• Possession counts as an act by definition, and constructive possession is where the litigation happens.
• Omissions are criminal only with a duty from statute, status, contract, assumption of care, or creation of the peril.

Sources

1. Legal Information Institute. (n.d.). Actus reus. Cornell Law School. law.cornell.edu
2. Wikipedia. (n.d.). Robinson v. California. en.wikipedia.org
3. Wikipedia. (n.d.). Powell v. Texas. en.wikipedia.org
4. Britannica. (2024). Criminal law: The elements of crime. britannica.com
5. Legal Information Institute. (n.d.). Model Penal Code. Cornell Law School. law.cornell.edu

Three tons of bomb casings, sold for eighty-four dollars

Joseph Morissette was a junk dealer in Michigan and a veteran of the Second World War. In 1948 he went deer hunting on a tract of land the Air Force used as a practice bombing range. He got no deer. What he did find were heaps of spent bomb casings, rusting in the weeds where they had lain for years, some of them stacked by government crews and left. He loaded three tons of them onto his truck in broad daylight, flattened them, sold them at a market, and cleared eighty-four dollars.

He was prosecuted under a federal statute punishing whoever knowingly converts property of the United States, and he testified that he thought the casings were abandoned. The trial judge would not let the jury consider that. He instructed that the only intent required was the intent to take the casings, which Morissette plainly had, and Morissette was convicted.

A unanimous Supreme Court reversed in Morissette v. United States, 342 U.S. 246 (1952). Justice Jackson's opinion is the best short essay on mens rea in the reports. Crime, he wrote, is generally constituted only from concurrence of an evil-meaning mind with an evil-doing hand, and when Congress borrows a common law offence like conversion without saying anything about intent, silence is not an abolition of the intent requirement. It is Congress assuming the requirement is already there.

That is the subject of this lesson: not whether the defendant did it, but what he must have had in his head while doing it, and about which parts of the offence.

The old vocabulary, and why it collapsed

For centuries the common law used a scattered inventory of mental state words: maliciously, wilfully, wantonly, feloniously, corruptly, with a depraved heart, with intent to defraud. There was no agreed hierarchy and no agreed content. Courts also split crimes into general intent (intent to do the prohibited act) and specific intent (an additional purpose beyond the act, as in burglary's breaking and entering with intent to commit a felony inside). Those two labels still appear in state opinions and still matter, because some defences, notably voluntary intoxication, are available only against specific intent crimes.

The problem was that nobody could reliably say what any given word meant in any given statute. The Model Penal Code's drafters solved it by throwing the vocabulary out and replacing it with four defined terms, arranged from most to least culpable. This is the single most successful law reform project of the twentieth century in the United States, and most state codes now use some version of it.

The four states, defined

The important structural line falls between recklessness and negligence. Recklessness is subjective: the defendant actually noticed the risk. Negligence is objective: he did not notice, and a reasonable person would have. Everything above the line involves awareness; everything below it involves the failure to be aware. That is why criminal negligence requires a gross deviation and not the ordinary carelessness that suffices in tort.

One worked contrast makes it stick. A man fires a rifle into a crowded room. If he wanted to kill the person he hit, that is purpose. If he aimed at someone else but knew the bullet would pass through and hit the victim, that is knowledge. If he fired at a wall to frighten people, consciously aware that a ricochet might kill and firing anyway, that is recklessness. If he genuinely never considered that a bullet might ricochet, when any reasonable adult would have, that is negligence.

Key idea: Purpose is desire, knowledge is practical certainty, recklessness is conscious risk taking, and negligence is the failure to perceive a risk you should have seen.

Element analysis, the move most students skip

Here is where the Model Penal Code is genuinely different from what came before. A crime is not one thing with one mental state attached. It is a set of material elements, and a mental state must be found for each of them. Three rules run the machinery:

• Section 2.02(3), the default. If a statute defines an element without saying which mental state applies, the state is established if the person acted purposely, knowingly, or recklessly. Recklessness is the floor.
• Section 2.02(4), the travel rule. When a statute states a single mental state without distinguishing among elements, that state applies to every material element unless a contrary purpose plainly appears.
• Section 2.02(5), the ladder. A higher mental state satisfies a requirement of a lower one. Proving purpose proves knowledge, recklessness, and negligence.

Now run a statute through it. Take: whoever knowingly receives stolen property with a value exceeding one thousand dollars is guilty of a felony. Break it into elements. The conduct element is receiving. The first attendant circumstance is that the property was stolen. The second attendant circumstance is that its value exceeded one thousand dollars. Under the travel rule, knowingly attaches to all three unless the statute says otherwise. So the prosecution must prove the defendant knew he was receiving, knew the property was stolen, and knew the value exceeded a thousand dollars.

Change one input and watch the result flip. Suppose the defendant bought a laptop for forty dollars from a stranger in a parking lot and told himself nothing. Value is easy: laptops cost more than a thousand dollars only sometimes, and if this one did not, the felony grade fails regardless of anything else. But suppose the laptop was worth two thousand and he knew it. Did he know it was stolen? He never asked. That is not automatically knowledge, which is precisely why the doctrine in the next section exists.

This is not an academic exercise. In Rehaif v. United States (2019), the Supreme Court held that to convict someone of unlawful firearm possession by a prohibited person, the government must prove the defendant knew he possessed a firearm and knew he belonged to the prohibited category. For decades, prosecutors had proved only the first. The Court applied element analysis and found the second element had been ignored. In Elonis v. United States (2015), a man was convicted for violent Facebook posts about his estranged wife under a jury instruction asking only whether a reasonable person would view them as threats. The Court reversed: a negligence standard was not enough for a federal criminal conviction when the statute was silent.

What matters here: Never ask what mental state a crime requires. Ask what mental state each element requires.

Wilful blindness

Back to the parking lot laptop. Courts will not let a defendant manufacture ignorance. Under the wilful blindness or ostrich doctrine, knowledge can be established where the defendant subjectively believed there was a high probability that the fact existed and took deliberate actions to avoid learning it. The Supreme Court stated that two-part test in Global-Tech Appliances v. SEB (2011), adopting a criminal law doctrine that had developed in cases like United States v. Jewell (9th Cir. 1976), where a driver was paid to take a car across the border and pointedly did not look inside a hidden compartment that held marijuana.

Note the limits, which juries are supposed to be instructed on. Recklessness is not enough. Suspicion is not enough. The defendant must have almost known and then chosen not to confirm it. A courier who was merely careless has not been wilfully blind.

Strict liability, and why Staples got his gun back

Strict liability offences dispense with mens rea for at least one element. They are disfavoured but real, and they cluster in two places. The first is public welfare offences: regulatory crimes involving food, drugs, hazardous materials, and traffic, usually carrying small penalties and no serious stigma, where the Court has accepted liability without fault since United States v. Balint (1922). The second is statutory rape in many states, where a reasonable mistake about the victim's age is no defence, a rule that draws consistent academic criticism and consistent legislative retention.

The best case for seeing the boundary is Staples v. United States, 511 U.S. 600 (1994). Staples possessed an AR-15 rifle that had been modified so that it fired automatically, making it a machine gun under the National Firearms Act. He testified he had never fired it automatically and did not know it could. The trial court told the jury his knowledge of that characteristic was irrelevant. The Supreme Court reversed. Guns, unlike grenades or narcotics, are lawfully owned by millions of Americans, so possession does not itself put an owner on notice that he is entering a regulated field; and the offence carried up to ten years, a penalty inconsistent with the small fines typical of public welfare offences. Silence in the statute therefore did not mean strict liability.

Two signals emerge for any statute you are asked to read: how severe is the punishment, and is the regulated item or activity one that already announces itself as dangerous and regulated? Heavy penalty plus ordinary item points strongly toward a mens rea requirement.

The upshot: Courts presume a mental state even in silent statutes, and the presumption strengthens as penalties rise and as the conduct looks more like everyday life.

Transferred intent, concurrence, and motive

Transferred intent handles bad aim. A shoots at B, misses, and kills C. A is guilty of murdering C; the intent follows the bullet. The doctrine applies within the same kind of harm. Intent to shoot a person does not transfer to the crime of destroying the window the bullet went through, which requires its own analysis.

Concurrence requires that the mental state and the act line up in time, and that the mental state actually motivate the conduct. A woman spends a month planning to kill her business partner, then accidentally runs him over on Tuesday before she has begun to carry out the plan. She is not a murderer, because the intent did not produce the act. Reverse the order and the problem returns: a man burgles a house, and only afterwards forms the intent to steal what he already carried out. Common law burglary required intent at entry, so timing decides the charge.

Motive is the reason behind the intent, and it is not an element of any offence. A man who steals bread to feed his child intends to steal; his motive may move a prosecutor's discretion, a jury's sympathy, or a judge's sentence, but it does not defeat the mens rea. The converse is true too: a good motive does not create a defence, and a bad motive does not supply a missing element. Motive is evidence, not law.

Causation, in two steps

For result crimes, the state must also connect conduct to result. Do it in two steps and you will not get lost.

Step one, actual cause. Would the result have occurred but for the defendant's conduct? If yes, causation fails here. Where two independent forces would each have sufficed, courts use a substantial factor test instead.

Step two, proximate cause. Is it fair to hold the defendant responsible, given what intervened? The Model Penal Code frames it as whether the actual result is too remote or accidental to have a just bearing on liability. Standard applications: an eggshell victim does not break the chain, so a punch that kills a man with a thin skull is still a homicide; ordinary medical negligence in treating the wound does not break the chain, but grossly abnormal treatment may; a victim's refusal of a blood transfusion on religious grounds does not break the chain; and a victim's foreseeable attempt to escape does not break it either.

Here is the pattern to memorise: an intervening cause that is dependent on the defendant's act, meaning a natural response to it, almost never relieves him. An independent intervening cause, meaning a coincidence, relieves him only if it was unforeseeable. A man leaves a stabbing victim on a beach at low tide and the tide drowns him: foreseeable, still homicide. The ambulance carrying the victim is struck by lightning: independent and unforeseeable, and the chain breaks.

Worth holding on to: Actual cause is a factual test, proximate cause is a fairness judgment, and foreseeability is what separates the intervening causes that matter from the ones that do not.

Common misconceptions

• A crime has one mental state. A crime has one mental state per material element, and the answers can differ across elements of the same offence.
• Silence in a statute means strict liability. Morissette, Staples, Rehaif, and Elonis all read a mental state into silent statutes; the presumption of fault is strong.
• Motive is an element the prosecution must prove. Motive is never an element; it is circumstantial evidence of intent and a sentencing consideration.
• Recklessness and negligence are two words for carelessness. Recklessness requires actual awareness of the risk; criminal negligence requires only that a reasonable person would have been aware, and demands a gross deviation.
• Suspecting something is enough for knowledge. Wilful blindness requires a belief in a high probability plus deliberate avoidance of confirmation, which is much more than suspicion.
• Any intervening event breaks causation. Foreseeable and dependent intervening causes, including ordinary medical error and a victim's refusal of treatment, do not.

Putting it together

• Morissette established that borrowing a common law crime without mentioning intent does not abolish the intent requirement.
• The Model Penal Code replaced a chaotic vocabulary with purposely, knowingly, recklessly, and negligently.
• The line between recklessness and negligence is awareness: subjective above, objective below.
• Element analysis assigns a mental state to each conduct, circumstance, and result element; recklessness is the default and higher states satisfy lower ones.
• Wilful blindness substitutes for knowledge only on a high probability belief plus deliberate avoidance.
• Strict liability survives for public welfare offences and statutory rape, and Staples shows how penalty severity and ordinariness of the item push against it.
• Transferred intent follows the harm; concurrence requires the intent to produce the act; motive is evidence, not an element.
• Causation runs but-for first, then proximate cause, where foreseeability decides which intervening events matter.

Sources

1. Legal Information Institute. (n.d.). Mens rea. Cornell Law School. law.cornell.edu
2. Wikipedia. (n.d.). Morissette v. United States. en.wikipedia.org
3. Wikipedia. (n.d.). Staples v. United States. en.wikipedia.org
4. Legal Information Institute. (n.d.). Strict liability. Cornell Law School. law.cornell.edu
5. Britannica. (2024). Criminal law: Mental element. britannica.com

Philadelphia, 1794: the year murder acquired degrees

Pennsylvania had a problem that was moral before it was legal. Under the common law inherited from England, murder was one offence and it carried one penalty: death. A poisoner who spent weeks planning and a tavern brawler who swung once too hard both hanged. Reformers in the new republic, many of them Quakers arguing for a narrower death penalty, wanted a way to keep capital punishment for the worst killings and remove it from the rest.

The solution the Pennsylvania legislature enacted in 1794 was to split the offence. Murder committed by poison or by lying in wait, or any other kind of wilful, deliberate and premeditated killing, or a killing committed in the perpetration of arson, rape, robbery, or burglary, became murder in the first degree, punishable by death. All other murder became murder in the second degree, punishable by imprisonment. Almost every American jurisdiction copied the structure, and two centuries later you are still reading its vocabulary in state codes. That single statute also planted the felony murder rule in American law in its modern form, which is the part still being fought over today.

This lesson takes homicide apart along those seams. Read it as a sorting problem: a person is dead, and the law must decide which box the killing goes in.

Malice aforethought, which means neither malice nor forethought

Common law murder is an unlawful killing of a human being with malice aforethought. The phrase is a fossil. It does not require ill will, and it does not require thinking ahead. It is a term of art covering four distinct mental states, any one of which is enough:

1. Intent to kill. The obvious one.
2. Intent to inflict grievous bodily harm. A man who beats another with a pipe intending to break his legs, and kills him, has murder even though he never wanted death.
3. Depraved heart, or extreme recklessness. Conduct showing extreme indifference to the value of human life: firing a rifle into an occupied house, dropping a concrete block from an overpass onto a highway.
4. Felony murder. A death caused during the commission of certain felonies, with the felony supplying the malice.

Everything else is manslaughter or no crime at all. Keep the four in mind as you read the table.

Remember: Malice aforethought is a label for four alternative mental states, not a requirement of hatred or planning.

What premeditation has to mean

The line between first and second degree turns on deliberation and premeditation, and courts have split over how much time that takes. Two cases mark the poles.

In Commonwealth v. Carroll (Pa. 1963), a man shot his wife in bed after a long marital argument, having thought about it, on his own testimony, for perhaps five minutes. The Pennsylvania court affirmed first degree murder and stated the traditional rule flatly: no time is too short for a wicked man to frame in his mind the scheme of murder. On that view, premeditation collapses into intent, since anyone who intends to kill must have formed the intent an instant before acting.

In State v. Guthrie (W. Va. 1995), the court refused that collapse. A dishwasher, needled by a coworker who snapped a towel at his nose, stabbed him to death. West Virginia held that first degree murder requires evidence that the defendant considered and weighed the decision, some appreciable time for reflection, not merely the instantaneous formation of intent. Otherwise, the court reasoned, the degrees the 1794 statute created would mean nothing.

Both rules are alive in American law. When you analyse a homicide problem, say which rule the jurisdiction uses before you answer, because the same facts can produce different degrees under each.

Provocation: the partial defence that cuts murder to manslaughter

A defendant who intended to kill can still avoid a murder conviction if he killed in the heat of passion on adequate provocation. This is not a full defence; it mitigates. Four elements are required: adequate provocation; the defendant was actually in the heat of passion; there was no reasonable cooling off period between provocation and killing; and the provocation caused the passion which caused the killing.

The historical approach was categorical. Only a closed list of events counted as adequate: a serious battery, mutual combat, an unlawful arrest, an assault on a close relative, and the discovery of one's spouse in the act of adultery. Words alone were never adequate, no matter how vicious, a rule most states still apply.

American courts moved gradually to a reasonable person standard, beginning with Maher v. People (Mich. 1862), which asked whether the provocation would cause an ordinary person to act from passion rather than judgment, and left it to the jury. That opened the category but also raised an obvious question: reasonable person means what, exactly, when we ask whether losing control was understandable?

The Model Penal Code went furthest, replacing provocation with extreme mental or emotional disturbance. Under that formulation a homicide that would otherwise be murder is manslaughter when committed under the influence of extreme mental or emotional disturbance for which there is a reasonable explanation or excuse, and the reasonableness is judged from the viewpoint of a person in the actor's situation under the circumstances as he believes them to be. That final clause imports a great deal of the defendant's own perspective, which is exactly the criticism made of it: applied loosely, it lets a jury excuse rage that the community should not accept. Several states adopted it; others rejected it for that reason.

The adultery category deserves the same scrutiny. It grew up in a legal culture that treated a wife as a form of property and a husband's violence on discovering her infidelity as understandable. A number of jurisdictions have narrowed or removed it, and a handful of states have legislated to bar or restrict provocation claims resting on the discovery of a victim's sexual orientation or gender identity, the so-called gay and trans panic defence. The doctrine is moving, and where a jurisdiction stands on this is worth checking rather than assuming.

Why this matters: Provocation asks not whether the defendant lost control but whether the law is prepared to say that losing control was understandable, which is a moral judgment wearing a doctrinal coat.

Involuntary manslaughter, and the negligence floor

Where there is no intent to kill and no extreme indifference, an unintended death may still be criminal. Two theories dominate. Criminally negligent homicide requires a gross deviation from reasonable care creating a substantial and unjustifiable risk of death, a standard well above ordinary tort negligence: leaving a loaded handgun where a five year old plays, or driving at eighty through a school zone. Unlawful act manslaughter, sometimes called misdemeanour manslaughter, holds a defendant for a death caused during a malum in se misdemeanour, though many modern codes have abolished or narrowed it because it can punish a death nobody could have foreseen.

The distinction from depraved heart murder is one of degree, and juries make it. Firing a gun into the ceiling of an occupied apartment building is closer to extreme indifference; leaving that gun unlocked in a drawer is closer to gross negligence.

Felony murder, and the long retreat from it

Under the felony murder rule, a death caused during the commission or attempted commission of a felony is murder, and the intent to commit the felony substitutes for malice. No intent to kill is needed, and in its strict form no negligence about the death is needed either.

What the rule can do is visible in People v. Stamp (Cal. Ct. App. 1969). Robbers held up a business; one victim, a sixty year old man with advanced heart disease, collapsed and died of a heart attack shortly after they fled. Nobody touched him. The court affirmed first degree murder: the robbery caused the fright, the fright caused the attack, and a felon takes his victim as he finds him.

Because the rule reaches that far, courts built limits around it.

• Inherently dangerous felony. Many states restrict the rule to enumerated felonies (arson, rape, robbery, burglary, kidnapping) or to felonies dangerous to human life.
• The merger rule. The underlying felony must have a felonious purpose independent of the killing. Otherwise every aggravated assault that caused death would automatically be murder, and manslaughter would vanish.
• Res gestae. The death must occur within the time, place, and causal ambit of the felony, including immediate flight.
• Agency versus proximate cause. When a police officer or victim kills someone, the majority agency rule holds the felons liable only for killings by a co-felon; a minority proximate cause rule holds them for any foreseeable death the felony set off, including the death of a co-felon shot by the victim.

The rule's standing has weakened. England abolished constructive malice in the Homicide Act 1957, and felony murder does not exist in most other common law countries. Michigan abolished it judicially in People v. Aaron (Mich. 1980), holding that malice must be proved. Hawaii and Kentucky have abolished it by statute. California narrowed it sharply by legislation in 2018, restricting murder liability to those who actually killed, who aided the killing with intent to kill, or who were major participants acting with reckless indifference to human life. Defenders answer that the rule deters the use of violence during felonies and expresses a real intuition that people who bring guns to robberies own what follows. Critics reply that the deterrence evidence is thin and that the rule most often falls on the least culpable participant, the lookout or the driver.

The point: Felony murder converts a felony into malice, and every limiting doctrine you learn is an attempt to keep that conversion from swallowing the law of manslaughter.

Who counts as a victim, and when

Two boundary questions still arise. At the beginning of life, the common law born alive rule required that the victim be born and breathing; most states have supplemented it with feticide statutes protecting an unborn child at some stage, and the details vary sharply by jurisdiction. At the end of life, the traditional test was cessation of heartbeat and breathing, which modern intensive care made unworkable; the Uniform Determination of Death Act of 1981 added irreversible cessation of all functions of the entire brain, and that standard is now general.

The old year and a day rule, which barred a homicide charge if the victim survived a year and a day after the injury, made sense when medicine could not trace causation over long periods. It has been abolished nearly everywhere, by statute or by decision, as you saw in the first lesson.

Common misconceptions

• Malice aforethought means the killer hated the victim and planned it. It is a technical label covering four mental states, including extreme recklessness and felony murder.
• Premeditation requires hours of planning. Some states require only an instant, others require appreciable reflection; you must name the jurisdiction's rule before answering.
• Provocation is a complete defence. It is a partial defence that reduces murder to voluntary manslaughter; the defendant is still convicted of a homicide.
• Insults can be adequate provocation. Words alone are traditionally never adequate, however severe.
• Felony murder requires that the felon cause the death directly. Under Stamp a fright-induced heart attack sufficed; the limits come from the dangerousness, merger, res gestae, and agency doctrines instead.
• Felony murder exists in every common law country. England abolished constructive malice in 1957, and several American states have abolished or sharply narrowed the rule.

What to carry forward

• Pennsylvania's 1794 statute created murder degrees to narrow the death penalty, and its structure still organises American homicide law.
• Malice aforethought covers intent to kill, intent to do grievous harm, depraved heart recklessness, and felony murder.
• First degree turns on premeditation, where Carroll and Guthrie represent opposite rules about how much reflection is required.
• Provocation reduces murder to voluntary manslaughter on four elements, with categorical, reasonable person, and Model Penal Code approaches in play.
• Involuntary manslaughter rests on gross negligence or on an unlawful act, and shades into depraved heart murder by degree.
• Felony murder substitutes felonious intent for malice; dangerousness, merger, res gestae, and agency limit it, and several jurisdictions have abolished or narrowed it.
• Born alive rules, feticide statutes, brain death standards, and the abolished year and a day rule define who counts as a homicide victim.

Sources

1. Legal Information Institute. (n.d.). Homicide. Cornell Law School. law.cornell.edu
2. Legal Information Institute. (n.d.). Felony murder doctrine. Cornell Law School. law.cornell.edu
3. Britannica. (2024). Homicide. britannica.com
4. Wikipedia. (n.d.). Felony murder rule. en.wikipedia.org
5. Bureau of Justice Statistics. (n.d.). Homicide data and reports. Office of Justice Programs. bjs.ojp.gov

Buffalo, 1984: a defendant argues the exemption is unfair to him

Mario Liberta appealed his New York convictions for forcibly raping and sexually assaulting his wife, Denise. The statute then exempted some married defendants, but it already excluded spouses living apart under a qualifying court order. The Libertas were living apart under an order of protection. In People v. Liberta, 64 N.Y.2d 152 (1984), the Court of Appeals held that the order brought him within that existing exception.

That left his constitutional argument. Why should a husband subject to this order be punishable when a husband still covered by the marital exemption could escape these charges for the same conduct? The court found no rational basis for the marital distinction. It also rejected the rape statute's gender restriction, applying the separate equal-protection test for sex classifications.

The remedy mattered. The court removed the marital exemptions from the two forcible-offence provisions and the gender exemption from the rape provision. It preserved the offences and affirmed Liberta's convictions. His conduct was already criminal under the law applicable when he acted. The decision did not first make every sexual offence between spouses criminal, and it did not decide every later question about spousal cases.

Keep that method as you read: identify the jurisdiction, the offence, and the date before applying a rule. This is general legal education, not advice about an individual case. The linked legal texts and reproductions discussed here were checked on September 28, 2026. The historical cases explain particular reforms; they are not a substitute for checking the law applicable to a later event.

Assault and battery, and the vocabulary problem

The traditional distinction separates contact from an attempt or a threatened contact. Modern statutes use the labels differently, so the name of a charge cannot supply its elements.

Battery, in the traditional account discussed in M.T.S., is an unlawful application of force that causes injury or an offensive touching. Physical injury is not essential to that account. California still defines battery separately: Penal Code section 242 requires a willful and unlawful use of force or violence upon another person. Read its mental-state requirement alongside the conduct requirement.

Assault may refer to attempted battery or, in a jurisdiction recognising that form, intentionally causing reasonable apprehension of imminent harmful or offensive contact. Apprehension means awareness of impending contact, not necessarily fright. Under the latter model, intentionally pointing an unloaded gun at a person who reasonably anticipates being shot illustrates an assault without a completed touching. This example does not resolve liability under every state's criminal statute.

For example, California Penal Code section 240 expressly requires an unlawful attempt coupled with present ability. Do not replace that language with the Model Penal Code's general substantial-step test for attempt. A different statute may use assault to describe completed injury. Aggravated assault describes a more serious grade, but the required weapon, injury, mental state, or protected-victim circumstance depends on the particular provision. An aggravating fact must match the statute; it does not automatically turn every touching into a felony.

New York's breathing-obstruction provisions show how grading works. Section 121.11 requires intent to impede normal breathing or blood circulation and specified conduct: pressure on the throat or neck, or blocking the nose or mouth. It is a class A misdemeanour. Section 121.12 adds a resulting stupor, loss of consciousness, or other physical injury or impairment and defines second-degree strangulation as a class D felony. Compare the elements before the labels. A prediction about future violence is not an element listed in either provision.

In short: Use the traditional assault-battery distinction to frame the question, then apply the jurisdiction's enacted definition and grading rules.

What the common law of rape required, and the four hurdles it built

The history recounted in Liberta and State in the Interest of M.T.S., 129 N.J. 422 (1992), shows how rape law combined narrow offence definitions with special barriers to proof. The older New Jersey statute required carnal knowledge of a woman forcibly and against her will. The following practices differed across places and periods; they were not one uniform code.

1. Force and resistance. Courts required proof of force, and many required the victim to have resisted, sometimes to the utmost. The practical result was that the complainant's conduct, not the defendant's, became the trial's subject.
2. The marital exemption. Liberta traced its implied-consent rationale to Matthew Hale's treatise. Hale asserted that marriage supplied consent a wife could not withdraw, without citing authority. Courts and legislatures later adopted exemptions. This history does not mean the exemption never appeared in enacted law: New York had codified it.
3. Corroboration. As M.T.S. recounts, some jurisdictions required evidence supporting the complainant's testimony before a conviction could stand. That special corroboration rule is different from a jury evaluating the credibility and sufficiency of all the evidence.
4. Cautionary instructions and prompt complaint. The same opinion describes special warnings about rape allegations and rules that treated delay in complaining with suspicion. These are historical practices, not instructions to infer consent or fabrication from a person's reporting delay.

Together these did not merely make convictions difficult. They encoded a suspicion of the complainant into the structure of the trial.

The reform, decade by decade

Reform changed several different legal questions. Removing a special proof requirement, changing an offence's elements, and limiting admissible evidence are separate steps.

Michigan's proof rules. Sections 750.520h and 750.520i, added by 1974 Act 266, effective April 1, 1975, state that corroboration and victim resistance are not required in prosecutions under sections 750.520b to 750.520g. The Michigan Judicial Institute's Sexual Assault Benchbook reproduces and explains these provisions. Testimony is evidence; the absence of a second eyewitness does not automatically defeat a prosecution. The prosecution must still prove the charged offence.

Rape shield rules. In proceedings governed by the Federal Rules of Evidence, Rule 412 generally excludes evidence offered to prove an alleged victim's other sexual behaviour or sexual predisposition. Under subsection (b)(1), a criminal court may admit specific sexual-behaviour evidence offered to identify another source of semen, injury, or other physical evidence; specific behaviour with the accused offered by the defendant to prove consent or offered by the prosecutor; and evidence constitutionally required for the defence. These are permissions for judicial consideration, not automatic admission.

Rule 412(c) requires a motion describing the evidence and its purpose, ordinarily at least 14 days before trial, notice to the victim, and a hearing outside public view before admission. The rule uses a different balancing test for civil cases in (b)(2). State proceedings have their own rules and statutes. Do not apply the federal list unchanged to a state case.

The marital exemption. Liberta changed New York's forcible-offence provisions in 1984. That holding cannot establish the status of every spousal exception elsewhere. For example, the Michigan benchbook quotes section 750.520l as allowing charges against a spouse but retaining an exception when the charge rests solely on the spouse being mentally incapable. A broad statement that all marital exemptions disappeared hides this kind of distinction.

Resistance and permission. In M.T.S., New Jersey's Supreme Court held that its physical-force element did not require extra force beyond penetration when the act occurred without affirmative and freely given permission. Permission could be communicated by words or actions in context. The court kept the burden on the State and addressed the defendant's reasonable belief in permission. A 2020 statutory amendment replaced the physical-force wording with language about coercion or absence of affirmative and freely given permission, as the published 2025 opinion in State v. K.W. explains. The 1992 wording is therefore a historical reference, not the present wording of the statute.

What matters here: Name exactly what changed and where. Michigan's corroboration rule, New York's severance decision, and New Jersey's definition of sexual assault solve different legal problems.

Three models of consent

These models help you compare legal definitions. They can overlap: a force-based offence may define force through the absence of permission. They do not replace the full elements or determine the burden of proof by themselves.

California Education Code section 67386 illustrates why the type of proceeding matters. As a condition of receiving state funds for student financial assistance, covered postsecondary institutions must adopt specified disciplinary policies for incidents involving students, on and off campus. The section requires affirmative, conscious, voluntary agreement, allows its withdrawal, and says silence or lack of resistance does not itself mean consent. It sets a preponderance-of-evidence standard for the disciplinary complaint. That section does not define the elements of a California criminal prosecution.

For a criminal comparison, California Penal Code section 261(a)(2) addresses intercourse against a person's will through specified force, violence, duress, menace, or fear. Other subdivisions address different circumstances. Do not stop after reading one subdivision. And do not transfer the campus burden of proof into criminal court. First identify the proceeding; next identify the applicable provision; then match the evidence to each element.

When consent cannot be given, and when it is void

Capacity concerns whether a person can give legally effective consent in the circumstances. California Penal Code section 261 supplies several distinct examples. Subsection (a)(3) addresses a person prevented from resisting by an intoxicating or other specified substance when the accused knew or reasonably should have known of that condition. Subsection (a)(4) addresses a person unconscious of the nature of the act when the accused knows it, including someone asleep. Drinking some alcohol is not, by itself, proof of either condition. Nor does a later gap in memory alone establish all the elements.

Disability also requires precision. Under section 261(a)(1) and (b)(2), the prosecution must establish incapacity at the time of intercourse and the specified knowledge requirement. Incapacity here means inability to understand the nature of the act or inability to act freely and voluntarily because of the specified disorder or disability. The inquiry must consider applicable mitigating measures and voluntary supports in place. The text expressly rejects a presumption that disability means inability to consent. A diagnosis or a conservatorship cannot replace the statutory inquiry. These are California provisions checked in their version effective January 1, 2026, not a nationwide test.

Fraud in the factum means deception about the nature of the act, unlike fraud in the inducement, a collateral lie used to obtain agreement. The labels help identify the issue, but the criminal consequence depends on the law. California section 261(a)(4)(C) and (D) covers specified deception about an act's essential characteristics or a false professional purpose; subsection (a)(5) separately addresses deceptive impersonation of a person known to the victim. It is broader than impersonation of a spouse alone. Do not infer from these provisions that every dishonest inducement satisfies the offence.

Key idea: Ask separately about actual agreement, legal capacity, deception, and the accused's required state of mind. One label cannot answer all four questions.

Statutory rape, and the argument about strict liability

Statutory rape is a common label for offences based on age, but the operative rules are specific. New York Penal Law section 130.05(3)(a) treats a person under seventeen as incapable of consent. To establish a particular charge, you must also read its act and age requirements. For example, section 130.25(4) to (6) addresses specified sexual contact by a person at least twenty-one with a person under seventeen. That example does not define all offences involving younger people.

New York section 15.20(3) provides that knowledge of a child's age is not an element of an age-based offence under that chapter, and mistake about age is no defence unless expressly provided. This is strict liability as to age, not a statement that every other element lacks a mental-state requirement. Other jurisdictions must be researched separately. A close-in-age provision may change liability, grading, or another consequence; do not assume its effect from an informal name.

Work the evidence question one step at a time

Suppose a defendant in a federal sexual-misconduct trial offers testimony about an alleged victim's unrelated past partners to argue that the person was likely to consent. First identify the purpose: it asks the jury to infer willingness on this occasion from other sexual behaviour. Rule 412(a) generally bars that use. A consent defence alone does not open all sexual history to examination.

Now change the purpose. Suppose specific evidence of another sexual encounter is offered to explain the source of semen found during an examination. Rule 412(b)(1)(A) may permit consideration of that evidence. The court must still follow the required procedure and decide admissibility. Even if admitted, evidence about the source of semen does not itself decide whether the charged encounter was consensual.

Finally separate admissibility from sufficiency. The first question asks what evidence the decision maker may consider. The second asks whether the admissible evidence proves the required elements. Removing a corroboration requirement does not guarantee conviction; finding an exception to a rape shield rule does not guarantee acquittal. You need the offence, the proof standard, and the evidence together.

Common misconceptions

• Assault means hitting someone. At common law the hitting is battery; assault is the attempt or the creation of reasonable apprehension, and modern statutes redefine the words.
• The marital exemption was never statutory. Liberta traced its rationale to Hale, but New York later enacted an exemption. The decision changed specified New York provisions.
• Victims must resist for a prosecution to succeed. Michigan's cited provisions expressly dispense with resistance. M.T.S. likewise rejected a requirement of resistance under the New Jersey provision it interpreted.
• A rape shield exception guarantees admission. Federal Rule 412 permits specified evidence to be considered for admission, subject to procedure and other applicable rules. Its civil test differs from its criminal exceptions.
• Affirmative consent is the criminal standard in California. California's 2014 statute sets the standard for campus disciplinary proceedings, not for criminal prosecution.
• Any alcohol use or disability proves incapacity. The California provisions discussed here require particular conditions and knowledge. Section 261 expressly forbids presuming inability to consent merely from disability.

Looking back

• Start with the traditional distinction between touching, attempt, and apprehension, then read the enacted offence. Its elements determine liability and grading.
• Liberta removed exemptions from specified New York forcible-offence provisions. It is not evidence that all jurisdictions or offences became identical.
• Michigan dispenses with resistance and corroboration under the cited provisions. M.T.S. explains a separate New Jersey reform concerning permission.
• Federal Rule 412 limits sexual-behaviour evidence, provides criminal exceptions and a separate civil test, and requires a procedure before admission.
• California's campus disciplinary standard and criminal provisions have different functions. Always identify which proceeding you are analysing.
• Capacity, fraud, and age require the full applicable rule, including knowledge requirements and exceptions. General models guide comparison; they do not decide a case.

Sources

1. New York Court of Appeals. (1984). People v. Liberta, 64 N.Y.2d 152, 158-173. Opinion reproduced in J. S. Gersen, Family Law Spring 2024, section 1.10.1. Harvard Law School H2O
2. Supreme Court of New Jersey. (1992). State in the Interest of M.T.S., 129 N.J. 422, 431-450. Opinion text at Justia. For the 2020 statutory change, see New Jersey Superior Court, Appellate Division. (2025). State v. K.W., A-2049-23, pp. 25-28. Opinion text at Justia
3. United States. (2025). Federal Rules of Evidence, Rule 412(a)-(d), pp. 7-8, edition dated December 1, 2025. United States Courts
4. California Legislature. (n.d.). Penal Code, sections 240 and 242, assault and battery.
5. California Legislature. (2025). Penal Code section 261, especially (a)(1)-(5) and (b)(2); amendment effective January 1, 2026. California Legislative Information
6. California Legislature. (2023). Education Code section 67386, especially (a)(1)-(4); amendment effective January 1, 2024. California Legislative Information
7. Michigan Judicial Institute. (n.d.). Sexual Assault Benchbook, sections 2.9 and 6.10(C)-(D), quoting MCL 750.520h, 750.520i, and 750.520l. Protections under criminal sexual conduct statutes; Witness testimony. Historical enactment notes: section 750.520h and section 750.520i, 2025 code text reproduced by Justia.
8. New York State Senate. (n.d.). Penal Law, sections 121.11 and 121.12, obstruction of breathing and second-degree strangulation.
9. New York State Senate. (n.d.). Penal Law, sections 15.20(3), 130.05(3)(a), and 130.25(4)-(6), age and offence-specific elements.
10. Legal Information Institute. (n.d.). Assault. Cornell Law School. Retrieved September 28, 2026. Optional background for terminology; use the cited primary provisions for criminal elements. Cornell Wex

London, 1799: a bank teller and a hole in the law

Joseph Bazeley worked as a teller at a London bank. A customer handed him a hundred pound note to deposit. Bazeley put it in his own pocket. Everyone agreed what he had done was dishonest, and the prosecution charged him with larceny, which was then a capital offence.

The judges acquitted him of larceny. Larceny required a trespassory taking, meaning a taking from the possession of another. The note had gone directly from the customer's hand to Bazeley's hand. The bank never possessed it. There was no possession to trespass against, so the defining element of the crime was missing, and the most obvious thief in London walked out of court.

Parliament passed an embezzlement statute within months. That sequence, a gap discovered in litigation and a statute enacted to close it, is the whole history of theft law in one episode. What you now read in a state penal code as a single crime called theft is a collection of patches sewn over holes that defendants found first.

Larceny, and why it protects possession rather than ownership

Common law larceny is the trespassory taking and carrying away of the personal property of another with the intent to permanently deprive the owner of it. Six components hide in that sentence:

• Trespassory: without the consent of the person in possession.
• Taking (caption): acquiring dominion and control.
• Carrying away (asportation): any movement, however slight. Lifting a television an inch off a shelf satisfies it.
• Personal property: at common law, tangible movable goods, not land, not services, and originally not intangibles, which is why statutes had to be written for electricity, gas, cable, and data.
• Of another: another's possession. You can commit larceny of your own car by taking it from the mechanic who holds a valid lien on it.
• Intent to permanently deprive: borrowing without permission is not larceny, which is why joyriding needed its own statute.

The fifth point is the one students misread. Larceny is not about who owns the thing. It is about who was holding it lawfully.

The point: Larceny protects possession, and every classic theft puzzle is really a question about who possessed the property at the moment intent formed.

The two patches, and the test that separates them

Two statutory offences fill the gaps Bazeley and others exposed.

Embezzlement is the fraudulent conversion of property by a person who is already in lawful possession of it. The bank teller, the trustee, the payroll clerk, the lawyer holding client funds. The defendant got the property legitimately; the crime is what he did afterwards.

False pretenses is obtaining title to property by a knowingly false representation of a past or existing fact, with intent to defraud. The buyer who pays with a check he knows is worthless has induced the seller to hand over ownership, not merely custody. Note two limits: a false promise about the future is traditionally not a false representation of fact, and mere opinion or sales puffery is not either.

There is a fourth member of the family. Larceny by trick covers deception that obtains only possession rather than title: renting a car with no intention of returning it. Because possession alone passed, the original taking is still treated as trespassory, and it remains larceny.

The distinction between custody and possession does real work. An employee handling the shop's cash register generally has custody only, with the employer retaining constructive possession, so taking from the till is larceny. A delivery driver entrusted with a truckload of goods for an out-of-state run generally has possession, so keeping the goods is embezzlement.

Consolidation, and the variance problem it solved

Dividing theft into three offences created an ugly practical problem. A prosecutor who charged larceny and proved embezzlement lost the case, not because the defendant was innocent but because the pleading did not match the proof. Defendants exploited it, arguing at each trial that they had actually committed the other crime.

Modern codes fixed this by consolidation. The Model Penal Code's theft article gathers larceny, embezzlement, false pretenses, extortion, receiving stolen property, and theft of services into one offence of theft, and provides expressly that an accusation of theft may be supported by evidence that it was committed in any manner that would be theft under the article, so long as the defendant is not unfairly surprised. Most states have adopted some version. Learn the historical categories anyway: they still explain what the elements mean and they still appear in appellate opinions.

Robbery, extortion, and burglary

Robbery is larceny from the person or presence of the victim, accomplished by force or by putting the victim in fear of immediate harm. Two details matter. The force must be more than the effort of taking, so a clean pickpocketing is larceny, while a purse snatch involving a struggle is robbery. And the force or fear must occur at or before the taking; jurisdictions differ on whether force used during immediate escape converts a completed larceny into robbery.

Extortion, historically blackmail, covers obtaining property by threats of future harm, including threats to accuse of a crime, to expose a secret, or to take official action. The clean line is timing: immediate harm to the person present is robbery, threatened later harm is extortion.

Burglary at common law had five elements, and modern statutes have discarded most of them. The common law required breaking and entering the dwelling house of another in the nighttime with intent to commit a felony inside. Modern codes typically require entering or remaining unlawfully in a building or occupied structure with intent to commit a crime, dropping the breaking requirement, the night requirement, and the limitation to dwellings, though many grade dwellings and night entries higher. Recall from the lesson on mens rea that the intent must exist at entry. A man who enters a store lawfully, then decides to steal, commits theft but not common law burglary, and modern remaining unlawfully language was written to reach the person who hides in the store until closing.

Receiving stolen property requires receiving property that is in fact stolen, knowing or believing it to be stolen, with intent to deprive the owner. Two recurring issues: the property must actually be stolen at the time, which is why sting operations using recovered goods produce attempt charges rather than completed offences in many states, and knowledge is often proved by circumstantial evidence such as price, place, and the seller's evasiveness. Wilful blindness, from the mens rea lesson, does a lot of work here.

Remember: Robbery is force now, extortion is harm later, and burglary is about an unlawful entry with a criminal purpose already formed.

Federal fraud, and how far a statute can stretch

Two federal statutes carry an enormous share of white collar prosecution. The mail fraud statute, 18 U.S.C. section 1341, and the wire fraud statute, section 1343, each require a scheme to defraud, plus the use of the mails or of interstate wires in furtherance of it. The mailing or the wire need not be fraudulent itself; a routine confirmation email will do.

That structure makes the statutes extraordinarily flexible, which is why federal prosecutors reach for them so often and why appellate courts have spent forty years pruning them. Three recent decisions show the trimming.

• Skilling v. United States (2010), arising from the collapse of Enron, addressed honest services fraud under section 1346. The Court held that reading the statute to cover any breach of a duty of honest services would raise vagueness problems, and confined it to bribery and kickback schemes.
• Kelly v. United States (2020), the New Jersey bridge lane closure case, reversed convictions because the object of the scheme was to exercise regulatory power for a political motive, not to obtain money or property. Wire fraud is a property crime, and corrupt purpose alone does not supply the missing element.
• Ciminelli v. United States (2023) rejected the right to control theory, under which depriving a victim of information relevant to an economic decision counted as a property deprivation. The Court held that intangible interest is not property under the statute.

A related area has moved the same way. Aggravated identity theft, 18 U.S.C. section 1028A, adds a mandatory two-year consecutive sentence when a defendant uses another person's means of identification during certain offences. Prosecutors read it broadly enough to attach to routine billing fraud. In Dubin v. United States (2023) the Court narrowed it, holding that the use of the identification must be at the crux of the criminality rather than merely ancillary to it.

Read those four cases together and you see an institutional pattern rather than four unrelated results: a statute broad enough to be useful invites expansion, and expansion invites a court to draw the line the legislature did not.

Why a dollar figure decides the grade

Nearly every theft statute grades by value, and the felony threshold is a policy choice with visible consequences. Thresholds vary widely among the states, and many were set decades ago and left to inflation, so a fixed dollar amount quietly criminalised more conduct each year. Between roughly 2001 and 2018 a large number of states raised their felony theft thresholds. Analyses comparing states that raised thresholds with states that did not found no resulting increase in property crime or larceny rates, which weakened the main argument against raising them.

The lesson generalises past theft. When a criminal statute keys liability to a number, that number is doing moral work, and it should be revisited as prices move.

The upshot: Grading rules are where legislatures make quiet decisions about who becomes a felon, and empirical evidence has begun to discipline them.

Common misconceptions

• You cannot steal your own property. Larceny protects possession, so taking your car from a mechanic with a valid lien can be larceny.
• Embezzlement means stealing large sums from a company. It means converting property you already lawfully possess, whatever the amount and whatever the setting.
• A broken promise about the future is false pretenses. The traditional rule requires a false representation of a past or existing fact; promises and opinions are excluded.
• Every taking with force is robbery. The force must exceed the effort of the taking; a clean pickpocketing remains larceny.
• Burglary requires breaking in at night to a house. Modern statutes have generally dropped breaking, night, and the dwelling limitation, though many grade those facts more severely.
• Mail and wire fraud reach any dishonest scheme. The object must be money or property, as Kelly held, and honest services fraud is limited to bribes and kickbacks after Skilling.

Pulling it together

• Bazeley's acquittal in 1799 shows why theft law is a set of statutory patches over the narrow common law of larceny.
• Larceny requires a trespassory taking and asportation of another's personal property with intent to permanently deprive, and it protects possession.
• Ask what the defendant held when intent formed: custody points to larceny, possession to embezzlement, title to false pretenses.
• Consolidated theft statutes ended the variance trap while preserving the old categories as interpretive tools.
• Robbery is force or fear of immediate harm at the taking; extortion threatens future harm; burglary needs criminal intent at entry.
• Mail and wire fraud require a scheme aimed at money or property, and Skilling, Kelly, Ciminelli, and Dubin have narrowed aggressive readings.
• Felony thresholds are policy choices, and raising them has not been shown to increase property crime.

Sources

1. Legal Information Institute. (n.d.). Larceny. Cornell Law School. law.cornell.edu
2. Legal Information Institute. (n.d.). Embezzlement. Cornell Law School. law.cornell.edu
3. Wikipedia. (n.d.). Skilling v. United States. en.wikipedia.org
4. Britannica. (2024). Theft. britannica.com
5. Bureau of Justice Statistics. (n.d.). Property crime data. Office of Justice Programs. bjs.ojp.gov

A man in a prison cell, convicted of crimes committed outside it

Walter and Daniel Pinkerton were brothers in Alabama who ran an illicit whiskey operation and were prosecuted for federal tax offences. Walter committed a series of substantive violations. During part of the relevant period, Daniel was in prison and could not have participated in any of them.

He was convicted of them anyway. In Pinkerton v. United States, 328 U.S. 640 (1946), the Supreme Court held that a member of a conspiracy is criminally liable for the substantive offences committed by co-conspirators in furtherance of the conspiracy, where those offences were reasonably foreseeable, so long as he had not withdrawn.

Start with the discomfort. It is one thing to punish a person for what he did, another to punish him for an agreement, and a third to punish him for what a partner did while he sat in a cell. This lesson is about that third territory: the offences that punish incomplete conduct and the doctrines that extend liability to people who never touched the crime.

Attempt: the intent, and the act that is enough

Every attempt requires two things: the intent to commit the target offence, and an act beyond mere preparation.

The intent element carries a trap. Attempt is a specific intent crime even when the completed offence is not. Murder can be committed with intent to inflict grievous bodily harm or with depraved heart recklessness, but attempted murder requires the intent to kill. It follows that there is no such crime as attempted felony murder or attempted involuntary manslaughter: you cannot intend to bring about an unintended death.

The act element has never had a single test. Three are worth knowing:

• Last act. The oldest and narrowest: the defendant must have done everything he believed necessary. Nearly abandoned, because it would require waiting until the trigger is pulled.
• Dangerous proximity. Associated with Justice Holmes: how close in time and space was the defendant to completion, and how grave the harm? In People v. Rizzo (N.Y. 1927), four armed men drove around New York looking for a payroll clerk they meant to rob. They never found him. The court reversed the attempt conviction: the intended victim was not present, so they were never dangerously near success.
• Substantial step. The Model Penal Code's test, now the majority. The act must be a substantial step strongly corroborative of the actor's criminal purpose. The Code lists examples that may qualify: lying in wait, following the intended victim, reconnoitring the place contemplated, unlawful entry, and possession of materials specially designed for the crime.

Notice the direction of travel. Dangerous proximity looks forward from the defendant's conduct toward the completed crime and asks how far is left. The substantial step test looks backward from the conduct and asks whether it confirms the purpose. Under the second test, the men in Rizzo are almost certainly guilty. Which test the jurisdiction uses can decide the case.

Key idea: Attempt requires purpose to complete the offence plus conduct that either brings the defendant dangerously near success or strongly corroborates his intent, depending on the jurisdiction.

Impossibility and abandonment

Factual impossibility is not a defence. A pickpocket who reaches into an empty pocket, a shooter who fires at a bed containing pillows rather than a person, a buyer who purchases what he thinks is cocaine and is in fact powdered sugar: each intended a crime and did everything he meant to do, and the failure was a matter of luck. The Model Penal Code puts the point crisply by asking whether the conduct would be a crime had the circumstances been as the defendant believed them to be.

Pure legal impossibility is a defence, and it is narrower than students expect. It applies only where the defendant intended to do something that is not a crime at all, believing wrongly that it was. A man who imports lace believing that importing lace is forbidden, when it is not, has committed no offence, because there is no crime for him to have attempted. A large middle category once called hybrid legal impossibility, covering mistakes about legal status such as receiving goods believed to be stolen that were not, has been abolished in most jurisdictions and folded into the factual side.

Abandonment divides jurisdictions. At common law the majority rule is that once the attempt is complete, abandonment is no defence, because the crime is already committed. The Model Penal Code allows a defence of renunciation where the defendant abandons the effort or prevents the crime, and the renunciation is complete and voluntary. That qualifier does the work: giving up because a police car appeared, or postponing until a better opportunity, or switching to a different victim, is not voluntary renunciation. Changing your mind because you decided it was wrong is.

Solicitation, and why refusal does not help the solicitor

Solicitation is asking, commanding, encouraging, or hiring another person to commit a crime, with the intent that the crime be committed. The offence is complete the moment the request is communicated. If the person solicited refuses, laughs, or reports the request to police, the solicitation has still occurred. If the person agrees, you now also have a conspiracy. If the crime is then attempted or completed, the solicitation merges into it and the solicitor is liable as an accomplice.

Conspiracy: an agreement, and everything that follows from it

Conspiracy is an agreement between two or more persons to commit a crime, with the intent to agree and the intent to achieve the criminal objective. Most jurisdictions add an overt act in furtherance, which can be trivial and entirely lawful, such as buying a map or making a phone call. The general federal conspiracy statute, 18 U.S.C. section 371, requires an overt act; the federal drug conspiracy statute, 21 U.S.C. section 846, does not, so the agreement alone completes that offence.

Three structural points:

• Bilateral or unilateral. The common law required at least two genuinely agreeing minds, so a defendant who agreed only with an undercover officer had no conspiracy. The Model Penal Code adopts a unilateral approach, asking whether this defendant agreed with another person, which permits conviction in the sting scenario. States are split.
• Scope. Is one large conspiracy proved, or several small ones? The distinction decides whose statements come in and who is tried with whom. In Kotteakos v. United States (1946), a single loan broker arranged fraudulent loans for many unconnected borrowers. The government charged one conspiracy; the Court found a wheel with no rim, because the borrowers had no interest in one another's transactions, and reversed convictions tainted by the mass trial.
• No merger. Unlike attempt and solicitation, conspiracy does not merge into the completed offence. A defendant may be convicted and sentenced for both the conspiracy and the crime it produced.

Why do prosecutors love conspiracy? Because of what comes with it, not because of the sentence. Venue lies wherever any overt act occurred. Co-conspirators may be tried together, so a jury hears the whole enterprise at once. Statements by one conspirator during and in furtherance of the conspiracy are admissible against every member as non-hearsay under Federal Rule of Evidence 801(d)(2)(E). The limitation period runs from the last overt act rather than from the agreement. And in federal court and many states, the Pinkerton rule attaches substantive liability for what partners did.

The traditional check is Wharton's rule, which says that where an offence by definition requires two participants, such as duelling or bribery, the agreement to commit it is not separately punishable as a conspiracy. It is a presumption about legislative intent and yields to a contrary statute.

What matters here: Conspiracy's real power is procedural, in venue, joinder, evidence, and timing, not in the sentence attached to the agreement.

Accomplice liability, and the knowledge Rosemond required

An accomplice is liable for the crime the principal commits. The federal provision, 18 U.S.C. section 2, states that whoever aids, abets, counsels, commands, induces, or procures the commission of an offence is punishable as a principal. Two elements are required:

1. Conduct: assistance or encouragement. It can be trivial and need not be necessary to the outcome. Acting as a lookout, driving, supplying a tool, or shouting encouragement all qualify. What does not qualify is mere presence: watching a crime, even approvingly, is not aiding it. Presence plus a prior agreement to be there in case help is needed does qualify.
2. Mental state: intent to assist the conduct, and intent that the underlying offence be committed. A merchant who sells an ordinary kitchen knife to a customer who then commits a stabbing is not an accomplice; a merchant who sells at an inflated price knowing and desiring the use may be.

Rosemond v. United States (2014) sharpened the mental element. Rosemond took part in a drug transaction during which someone fired a gun, and was convicted of aiding and abetting the use of a firearm during a drug crime. The Court held that liability requires advance knowledge that a confederate would carry a gun, meaning knowledge at a point when the defendant still had a realistic opportunity to withdraw. Learning of the gun only when it appears does not make him an aider and abettor of the firearm offence, because he cannot be said to have chosen to assist an armed crime.

Two further doctrines are worth naming. The natural and probable consequences rule extends accomplice liability to further crimes that were a foreseeable outgrowth of the one the accomplice intended to assist. It has been criticised for imposing murder liability on the basis of negligence, and it is in retreat: California abolished it for murder in its 2018 legislation. And an accessory after the fact is a separate, lesser offence: someone who, knowing a felony was committed, helps the offender avoid arrest or punishment. That person is not liable for the underlying felony.

Two counterintuitive consequences follow from the derivative structure. An accomplice can sometimes be convicted of a greater offence than the principal, as where the accomplice acts with premeditation while the principal kills in the heat of passion. And withdrawal is possible but demanding: the accomplice must communicate the withdrawal in time and neutralise the assistance already given, which for a supplied weapon usually means retrieving it or warning police.

So what?: Accomplice liability turns on a choice to help a particular crime, which is why advance knowledge and effective withdrawal both matter so much.

Common misconceptions

• An attempt requires getting close to completing the crime. Under the majority substantial step test, conduct strongly corroborating the purpose suffices even at a distance from success.
• It is a defence that the crime could not have worked. Factual impossibility is never a defence; only the narrow category of pure legal impossibility is.
• Backing out always cancels an attempt. The common law majority allows no abandonment defence once the attempt is complete, and the Model Penal Code requires renunciation that is both complete and voluntary.
• A solicitation fails if the other person refuses. The offence is complete when the request is communicated with the required intent.
• Conspiracy merges into the completed crime. It does not; a defendant may be punished for both, unlike attempt and solicitation.
• Being present and approving makes you an accomplice. Mere presence is insufficient; some assistance or encouragement, with intent, is required.

What you now know

• Pinkerton makes a conspirator liable for reasonably foreseeable substantive crimes committed by partners in furtherance of the agreement.
• Attempt requires intent to complete the offence plus an act beyond preparation, tested by dangerous proximity or, in most states, a substantial step.
• Factual impossibility is no defence; pure legal impossibility is, and the hybrid category has largely disappeared.
• Renunciation must be complete and voluntary, which excludes abandonment prompted by risk of detection or a better opportunity.
• Solicitation is complete on communication; conspiracy requires an agreement, intent, and usually an overt act, and does not merge.
• Conspiracy's advantages are procedural: venue, joinder, co-conspirator statements, and a limitation period running from the last overt act.
• Accomplice liability needs assistance plus intent that the offence be committed, and Rosemond requires advance knowledge of an armed confederate.
• Accessory after the fact is a distinct lesser offence, and withdrawal requires timely communication and neutralising prior help.

Sources

1. Legal Information Institute. (n.d.). Conspiracy. Cornell Law School. law.cornell.edu
2. Legal Information Institute. (n.d.). Accomplice. Cornell Law School. law.cornell.edu
3. Wikipedia. (n.d.). Pinkerton v. United States. en.wikipedia.org
4. Wikipedia. (n.d.). Rosemond v. United States. en.wikipedia.org
5. Britannica. (2024). Conspiracy. britannica.com

A subway car in December 1984, and an argument about one word

On 22 December 1984, four young men approached Bernhard Goetz on a Manhattan subway train and asked him for five dollars. Goetz, who had been mugged before and carried an unlicensed revolver, drew it and fired five shots. All four were wounded; one, Darrell Cabey, was left paralysed.

The legal fight that followed was not about what happened but about a single word in New York's justification statute. The statute allowed deadly force where the defendant reasonably believes it necessary. The prosecutor had told the grand jury to consider what a reasonable man in the defendant's situation would believe. Lower courts read that phrase as smuggling in a subjective test and dismissed the charges.

In People v. Goetz (N.Y. 1986) the Court of Appeals reinstated them. Reasonably believes, it held, means a belief that is both honestly held and objectively reasonable. A jury may take into account the defendant's own circumstances, including relevant prior experiences and what he knew about his assailants, but the ultimate question is what a reasonable person in those circumstances would have believed, not what this defendant sincerely felt. A trial jury later acquitted Goetz of the shooting charges and convicted him only of unlawful gun possession.

Hold that distinction, because it runs through every defence in this lesson. Whose perspective governs, and how far does the law bend the standard toward the individual defendant?

Justification is not excuse

The prosecution has proved actus reus, mens rea, and causation. The defendant still walks free if a defence applies, and defences come in two families that are often blurred and should not be.

A justification says the conduct was permissible, even right, in the circumstances. Society does not condemn it. Self-defence, defence of others, defence of property, necessity, and lawful law enforcement force are justifications.

An excuse says the conduct was wrongful but this actor is not blameworthy. Insanity, duress, infancy, and involuntary intoxication are excuses.

The distinction is not academic. Three consequences follow. You may lawfully assist someone acting under a justification, but assisting an excused actor may itself be criminal. You may not lawfully resist justified force, but you may resist an excused attacker, since his conduct is still unlawful. And a justification typically produces a full acquittal, while some excuses produce a special verdict with civil commitment attached.

The core of it: A justification denies that the act was wrong; an excuse concedes it was wrong and denies that the actor is to blame.

Self-defence: four requirements

A person may use force against another when he reasonably believes such force is necessary to defend against an imminent unlawful use of force. Break that into four checks and run them in order.

1. Unlawful threat. The force threatened must be unlawful. You may not use self-defence against a lawful arrest, even a mistaken one, in most states.
2. Imminence. The threat must be immediate, not past and not merely expected. Retaliation for yesterday is revenge; preemption against next week is not self-defence.
3. Necessity. Force must be needed, which is why the retreat question below matters.
4. Proportionality. The force used must not exceed what is needed. Deadly force, meaning force likely to cause death or serious bodily injury, is permitted only against death, serious bodily injury, or, in most states, an enumerated forcible felony such as rape, kidnapping, or robbery.

Each is filtered through the reasonable belief standard that Goetz defined. A defendant who is genuinely but unreasonably afraid fails the standard. Many states soften that result through imperfect self-defence, which reduces murder to voluntary manslaughter where the belief was honest but unreasonable, or where the defendant was the initial aggressor.

The aggressor rule and the retreat question

An initial aggressor generally forfeits the right to self-defence. He can regain it in two ways: by withdrawing from the encounter and communicating the withdrawal, or, in most jurisdictions, where he began with non-deadly force and the other party escalated to deadly force, leaving him facing death without a chance to retreat.

On retreat, American jurisdictions split, and the split is old. The majority no-retreat rule, sometimes called the true man rule, holds that a person who is not the aggressor need not retreat before using deadly force. The minority retreat rule requires retreat before deadly force if it can be done in complete safety. Every retreat jurisdiction recognises the castle doctrine exception: there is no duty to retreat from your own home.

Since 2005, when Florida enacted the first modern statute, roughly thirty states have passed stand your ground laws. These do more than codify the no-retreat rule. They typically add a presumption that a person who forcibly and unlawfully enters a dwelling or occupied vehicle intends to do serious harm, and often provide civil and criminal immunity determined at a pretrial hearing rather than by a jury at trial. That procedural feature is easy to overlook and does a great deal of work.

The empirical question has been studied. A 2017 analysis published in JAMA Internal Medicine examined Florida's homicide rates before and after the 2005 law and found a substantial increase in homicide and firearm homicide that was not matched in comparison states without such laws. Other studies have reported racial disparities in which claims succeed. Supporters answer that people should not be legally obliged to flee from an attacker and that the earlier rule effectively punished victims for judgment calls made in seconds. Both the statistical findings and the moral claim are serious, and a lesson that pretended otherwise would be lying to you.

Why this matters: Whether the law requires retreat, and who decides the immunity question, changes outcomes more than any refinement of the reasonable belief test.

The imminence problem, and battering evidence

The hardest self-defence cases involve defendants who killed an abuser during a lull rather than during an attack. State v. Norman (N.C. 1989) is the standard example. Judy Norman had endured decades of extreme violence from her husband, including being forced into prostitution and beaten with objects; she shot him while he slept. The trial court refused a self-defence instruction, and the North Carolina Supreme Court agreed: however brutal the history, the threat at the moment of the killing was not imminent.

Courts and legislatures have responded not by abolishing imminence but by changing what the jury may hear. Most states now admit expert testimony on battering and its effects, which explains why a defendant may perceive an attack as imminent that an outsider would not, why she may not have left, and why her assessment of danger may be more accurate than a stranger's. This is evidence bearing on reasonableness; it is not a separate defence, and calling it battered woman syndrome as though it were a diagnosis that excuses conduct misstates the law. Some states have also created clemency review processes for defendants convicted before such evidence was admissible.

Defending other people, and defending things

For defence of others, jurisdictions split. The majority rule lets the defender stand in the shoes of the person he protects but judges his conduct by reasonable appearances, so a person who reasonably but mistakenly believes he is stopping an assault is protected. The minority alter ego rule gives the defender exactly the rights the defended person actually had, so if the apparent victim was in fact the aggressor, the intervener is liable. The scenario that separates them is real: a plainclothes officer struggling with a suspect, and a passerby who intervenes on the wrong side.

For defence of property, the rule is short. Reasonable non-deadly force may be used to prevent an imminent unlawful taking or damage. Deadly force is never permitted to protect property alone. That is why spring guns and other mechanical devices are unlawful: in Katko v. Briney (Iowa 1971), a civil case that every criminal law course borrows, a shotgun rigged to fire at anyone opening a door in an unoccupied farmhouse maimed a trespasser, and the owners were held liable. The Model Penal Code states the principle directly, forbidding devices designed to cause death or serious harm. A person defending an occupied home may still have a self-defence claim, because there the interest at stake is the occupants, not the furniture.

Necessity, and the boat that ate the cabin boy

Necessity, the choice of evils defence, applies where breaking the law avoids a greater harm. Five requirements are standard:

• the harm to be avoided was imminent;
• there was no reasonable legal alternative;
• the harm avoided was greater than the harm caused, judged objectively;
• the defendant was not at fault in creating the situation;
• the legislature has not already resolved the balance the other way.

Easy applications: breaking into a cabin to escape a blizzard, speeding to a hospital, destroying part of a structure to create a firebreak. The Supreme Court's decision in United States v. Bailey (1980) added a practical condition in the escape context: a prisoner who flees intolerable conditions must offer evidence of a bona fide effort to surrender once the emergency has passed.

The hardest case is the oldest one. In 1884 the yacht Mignonette sank in the South Atlantic and four men escaped in an open boat. After weeks adrift, with no food or water, Dudley and Stephens killed the cabin boy, Richard Parker, who was already gravely ill, and the survivors ate his body. Rescued four days later, they were tried for murder. In R v. Dudley and Stephens (1884) the court held that necessity is no defence to murder, and it declined to make a rule that would require judges to decide whose life is worth less. The men were sentenced to death and the sentence was commuted to six months. American courts have almost uniformly followed the holding, and the Model Penal Code is the notable dissenter, permitting the defence in principle where a genuinely lesser evil is chosen.

In short: Necessity asks a court to endorse a choice between harms, which is why it is available for property and liberty and almost never for killing.

A note on police use of force

Officers act under a justification of their own, and two decisions define its outer limits. Tennessee v. Garner (1985) held that the old common law rule permitting deadly force against any fleeing felon is unconstitutional; deadly force to prevent escape requires probable cause that the suspect poses a significant threat of death or serious injury. Graham v. Connor (1989) set the standard for non-deadly force as objective reasonableness judged from the perspective of a reasonable officer on the scene, without the benefit of hindsight. Notice how closely that tracks Goetz: the same tension between an objective rule and a perspective taken from inside the moment. Use of force policy, training, and accountability are the subject of the site's Introduction to Criminal Justice course.

Common misconceptions

• Self-defence requires that you actually be in danger. A reasonable belief in the need for force suffices, and honest but unreasonable belief may reduce murder to manslaughter.
• Justification and excuse are interchangeable words. They differ in what they claim and in what follows for accomplices, resistance, and the form of the verdict.
• You may use deadly force to stop a thief. Deadly force is never justified to protect property alone; spring guns are unlawful for that reason.
• Battered woman syndrome is a defence. Expert evidence about battering informs the reasonableness of the defendant's perception; it is evidence, not a separate excuse.
• Stand your ground laws merely abolish the duty to retreat. They also commonly add presumptions of reasonable fear and pretrial immunity hearings, which change results independently.
• Necessity can justify killing an innocent person. Dudley and Stephens holds otherwise, and almost all American courts agree.

The takeaway

• Goetz settled that reasonably believes means honestly and objectively reasonable, with the defendant's circumstances admissible.
• Justifications say the act was permissible; excuses say the actor was not blameworthy, and the difference affects accomplices, resistance, and verdicts.
• Self-defence requires an unlawful, imminent threat, necessity, and proportionality; deadly force needs a deadly or forcible felony threat.
• Aggressors forfeit the defence unless they withdraw and communicate, or face escalation to deadly force.
• Retreat rules split; the castle doctrine is universal, and stand your ground statutes add presumptions and immunity hearings.
• Norman shows the imminence barrier in battering cases, which evidence rules rather than doctrine have addressed.
• Defence of others follows either a reasonable appearance or an alter ego rule; deadly force for property alone is never justified.
• Necessity requires imminence, no legal alternative, a genuinely lesser evil, clean hands, and no contrary legislative choice, and is barred for murder.

Sources

1. Legal Information Institute. (n.d.). Self-defense. Cornell Law School. law.cornell.edu
2. Wikipedia. (n.d.). People v. Goetz. en.wikipedia.org
3. Wikipedia. (n.d.). R v Dudley and Stephens. en.wikipedia.org
4. Legal Information Institute. (n.d.). Necessity. Cornell Law School. law.cornell.edu
5. Wikipedia. (n.d.). Tennessee v. Garner. en.wikipedia.org

Whitehall, January 1843

Daniel M'Naghten, a Glasgow woodturner who believed the Tory government was persecuting him, walked up behind a man in Whitehall and shot him in the back. He had aimed at Prime Minister Robert Peel. The man he shot was Edward Drummond, Peel's private secretary, who died five days later.

Nine medical witnesses testified for the defence. The jury acquitted M'Naghten on the ground of insanity, and the public reaction was ferocious enough that the House of Lords summoned the judges and put a set of questions to them. The judges' answers, delivered later that year, became the M'Naghten rules: to establish a defence on the ground of insanity, it must be proved that at the time of the act the accused was labouring under such a defect of reason, from disease of the mind, as not to know the nature and quality of the act, or, if he did know it, not to know that what he was doing was wrong.

Nearly two centuries later, roughly half the American states still use a version of that test. This lesson covers the excuses: the defences that concede the conduct was wrong and deny that this defendant should be blamed for it.

Three questions that are constantly confused

Before any test, separate three distinct legal questions that all involve mental illness.

• Insanity asks about the defendant's mental state at the time of the offence. It is a defence to the charge.
• Competence to stand trial asks about his mental state now. Under Dusky v. United States (1960), a defendant must have sufficient present ability to consult with his lawyer with a reasonable degree of rational understanding, and a rational as well as factual understanding of the proceedings. An incompetent defendant is not acquitted; the case is suspended while he is treated.
• A psychiatric diagnosis is neither. Insanity is a legal conclusion. A defendant may have a serious diagnosed illness and still fail every insanity test, and diagnosis alone establishes nothing.

Remember: Insanity is about then, competence is about now, and a diagnosis by itself decides neither.

Four tests, and what each one asks

Two design choices distinguish them. The first is cognitive versus volitional: M'Naghten asks only what the defendant understood, while irresistible impulse and the Model Penal Code's second clause also ask what he could control. The second is absolute versus substantial: M'Naghten's know is all or nothing, while the Code's lack of substantial capacity to appreciate admits degrees, and appreciate means more than intellectual awareness. A defendant who can recite that killing is illegal but cannot grasp what it means may satisfy the Code and fail M'Naghten.

Durham is the interesting failure. Decided by the District of Columbia Circuit in 1954, it asked simply whether the act was the product of mental disease, on the theory that psychiatry rather than law should define the categories. In practice it handed the verdict to expert witnesses, since the whole question turned on their testimony, and the same court abandoned it in 1972.

Hinckley, and the reform that followed within two years

On 30 March 1981 John Hinckley Jr. shot President Reagan and three other men outside a Washington hotel, having concluded that the act would win the attention of an actress he had never met. He was tried in federal court under the Model Penal Code test, where the prosecution bore the burden of proving sanity beyond a reasonable doubt. In June 1982 the jury acquitted him by reason of insanity.

Congress responded with the Insanity Defense Reform Act of 1984, which did three things at once. It narrowed the federal test to the cognitive prong alone, requiring that a severe mental disease or defect left the defendant unable to appreciate the nature and quality or the wrongfulness of his acts. It shifted the burden to the defendant, who must now prove insanity by clear and convincing evidence. And it barred expert witnesses from stating an opinion on the ultimate question of whether the defendant had the mental state constituting an element of the offence.

States moved too. Many narrowed their tests or shifted burdens; several adopted a guilty but mentally ill verdict, which produces a conviction and a sentence with treatment attached rather than an acquittal. Four states, Kansas, Montana, Idaho, and Utah, abolished the affirmative insanity defence altogether, permitting evidence of mental illness only to negate the mental element the prosecution must prove. In Kahler v. Kansas (2020) the Supreme Court upheld that approach, holding that due process does not require a state to adopt a moral incapacity test, and in Clark v. Arizona (2006) it had already allowed states to channel and restrict how mental illness evidence is used.

Two facts belong beside the outrage. The insanity defence is raised in roughly one percent of felony prosecutions and succeeds in a minority of those, so it accounts for a very small share of case outcomes. And defendants found not guilty by reason of insanity are typically committed to secure psychiatric facilities, frequently for longer than the prison term the conviction would have carried. Hinckley himself remained in institutional care for decades, moving to conditional release in 2016 and receiving unconditional release only in 2022.

The point: The insanity defence is rare, usually unsuccessful, and rarely a shortcut to freedom, which is the opposite of the impression the famous cases leave.

Duress: someone else's threat

Duress excuses a defendant who commits a crime because another person threatened him. The traditional elements are a threat of imminent death or serious bodily injury to the defendant or another, a well-grounded fear that the threat will be carried out, no reasonable opportunity to escape, and no fault of the defendant in exposing himself to the threat, as by joining a violent gang.

The Model Penal Code reframes it around a standard rather than a list: the defence applies where a person of reasonable firmness in the defendant's situation would have been unable to resist. That formulation drops the strict imminence requirement and drops the limitation to threats of physical harm.

The traditional rule is that duress is no defence to murder. A person may not save his own life by taking an innocent one, and the Model Penal Code is again the outlier in principle. In federal court, Dixon v. United States (2006) holds that the defendant bears the burden of proving duress by a preponderance of the evidence.

Duress and necessity are cousins, and the classic distinction is the source of the pressure: duress is a human threat and works as an excuse, while necessity is pressure from circumstances and works as a justification. The distinction is rough, and modern codes often blur it, but it explains why duress is treated as excusing a wrongful act rather than approving it.

Intoxication, which almost never helps

Voluntary intoxication is not a defence. In many states it may still negate a specific intent, so a defendant too drunk to form the intent to permanently deprive may defeat a larceny charge while remaining liable for a general intent offence. The Model Penal Code makes the point sharply for recklessness: if the defendant would have been aware of the risk had he been sober, his unawareness because of voluntary intoxication is immaterial. And states are free to go further. In Montana v. Egelhoff (1996) the Supreme Court upheld a statute barring juries from considering voluntary intoxication at all.

Involuntary intoxication is different and can be a complete defence where it produces a condition equivalent to insanity. It covers intoxication that was coerced, taken by mistake as to the substance, produced by an unexpected reaction to properly prescribed medication, or pathological, meaning grossly excessive relative to the amount consumed and unknown to the defendant.

Mistake, and the narrow exceptions to ignorance of the law

Mistake of fact is not really a defence at all. It is an argument that the prosecution cannot prove the mental element. The analysis is mechanical once you have done element analysis: if the mistake means the defendant lacked the required mental state as to an element, he is not guilty. Traditional courts asked whether the mistake was reasonable for general intent crimes and accepted any honest mistake for specific intent crimes. For a strict liability element, no mistake helps at all, which is what makes statutory rape's age element so severe.

Mistake of law is generally no defence. If it were, the more ignorant a person, the more freedom he would enjoy. Three narrow exceptions exist:

1. Official reliance. Reasonable reliance on an official statement of the law, in a statute, judicial decision, or an official interpretation by the person charged with administering the law, later determined to be invalid. Advice from your own lawyer does not count.
2. Lack of fair notice. In Lambert v. California (1957), a Los Angeles ordinance required convicted felons to register with police within five days of arriving in the city. Lambert had lived there for years and had no idea. The Court reversed her conviction: where the conduct is wholly passive, involves no circumstances that should alert a person to a duty, and the violation is unaccompanied by any activity giving notice, punishment without knowledge violates due process. The exception is real but has been read very narrowly since.
3. Knowledge of the law as an element. Some statutes, especially tax and regulatory offences, require that the defendant acted wilfully, meaning with knowledge that his conduct was unlawful. In Cheek v. United States (1991), an airline pilot stopped filing returns after being persuaded that wages are not income. The Court held that a genuine good faith misunderstanding of the tax laws negates wilfulness even if the belief is objectively unreasonable, because the statute made knowledge an element. It then drew a firm line: a belief that the tax laws are unconstitutional is not a misunderstanding of what the law requires but a disagreement with it, and it is no defence.

Key idea: Mistake of fact defeats a mental element; mistake of law defeats nothing unless the defendant relied on an official statement, had no fair notice, or faced a statute that made knowledge of the law an element.

Infancy and entrapment

Infancy at common law was tiered: a child under seven was conclusively incapable of crime, a child between seven and fourteen was presumed incapable subject to rebuttal, and a person of fourteen or over was tried as an adult. Modern practice replaced the presumptions with a separate juvenile system, with transfer or waiver provisions permitting prosecution of older juveniles as adults for serious offences. The institutional design of juvenile justice belongs to the Introduction to Criminal Justice course; what matters here is that age operates through jurisdiction rather than through an element.

Entrapment is a defence when the government originates a crime and induces someone not otherwise disposed to commit it. Two tests compete. The majority and federal subjective test focuses on the defendant's predisposition: government inducement plus a defendant who was not already ready and willing. The minority objective test, favoured by the Model Penal Code, focuses on the government's conduct and asks whether its methods created a substantial risk that an ordinary law-abiding person would commit the offence. Jacobson v. United States (1992) shows the subjective test biting: federal agents spent about two and a half years, through fictitious organisations and repeated mailings, working on a man who had once lawfully ordered magazines, until he ordered illegal material. The Court reversed, holding the government had failed to prove predisposition independent of its own campaign.

Common misconceptions

• Insanity and incompetence are the same. Insanity concerns the time of the offence and is a defence; incompetence concerns the present and suspends the case.
• An insanity acquittal means going home. Defendants found not guilty by reason of insanity are usually committed, often for longer than the corresponding prison term.
• The insanity defence is used constantly. It appears in about one percent of felony prosecutions and succeeds in a minority of those.
• Every state must offer an insanity defence. Kahler v. Kansas held that due process does not require a moral incapacity test, and four states allow mental illness evidence only to negate mens rea.
• Being drunk reduces every charge. Voluntary intoxication may negate specific intent in some states, is immaterial to recklessness under the Model Penal Code, and can be excluded entirely.
• Not knowing the law is a defence if you tried to check. Only reliance on an official statement of the law counts; advice from your own lawyer does not.

Summing up

• The M'Naghten rules came from the 1843 acquittal of Daniel M'Naghten and still govern in roughly half the states.
• Insanity, competence under Dusky, and psychiatric diagnosis are three different questions.
• The four tests differ on cognitive versus volitional capacity and on absolute versus substantial incapacity; Durham failed by handing the verdict to experts.
• The 1984 federal reform narrowed the test, shifted the burden to the defendant, and limited ultimate issue testimony after the Hinckley acquittal.
• Duress requires a human threat, imminence, no escape, and clean hands, and traditionally does not excuse murder.
• Voluntary intoxication rarely helps and may be excluded entirely; involuntary intoxication can be a full defence.
• Mistake of fact negates a mental element; mistake of law is excused only by official reliance, absent fair notice, or a wilfulness element as in Cheek.
• Infancy now operates through juvenile jurisdiction, and entrapment turns on predisposition in most courts and on government methods under the Model Penal Code.

Sources

1. Legal Information Institute. (n.d.). Insanity defense. Cornell Law School. law.cornell.edu
2. Wikipedia. (n.d.). M'Naghten rules. en.wikipedia.org
3. Wikipedia. (n.d.). Kahler v. Kansas. en.wikipedia.org
4. Wikipedia. (n.d.). Cheek v. United States. en.wikipedia.org
5. Legal Information Institute. (n.d.). Duress. Cornell Law School. law.cornell.edu

A glass booth on Sunset Boulevard

In 1965 Charles Katz was making a living transmitting wagering information on college basketball games. He used a bank of public telephone booths on Sunset Boulevard in Los Angeles, and he shut the door behind him. FBI agents had taped a microphone and recorder to the roof of two of the booths, outside the glass. They never entered, never drilled, never touched the interior.

Under the law as it then stood, that was not a search. Olmstead v. United States (1928) had held that wiretapping without a physical trespass into a constitutionally protected area fell outside the Fourth Amendment entirely, since conversations are not persons, houses, papers, or effects.

Katz v. United States, 389 U.S. 347 (1967), overruled that. The Fourth Amendment protects people, not places, the Court held. What a person knowingly exposes to the public is unprotected, but what he seeks to preserve as private, even in an area accessible to the public, may be constitutionally protected. Katz had shut the door and paid the toll; he was entitled to assume the words he spoke would not be broadcast to the world.

The rule everyone actually applies is not in the majority opinion. It is in Justice Harlan's concurrence: a search occurs where a person has exhibited an actual, subjective expectation of privacy, and that expectation is one society is prepared to recognise as reasonable. Six decades of doctrine have been built on that sentence.

The order of the questions

The Fourth Amendment protects the right of the people to be secure in their persons, houses, papers, and effects against unreasonable searches and seizures, and provides that no warrants shall issue but upon probable cause, supported by oath or affirmation, and particularly describing the place to be searched and the persons or things to be seized.

Analyse any problem in three steps, in this order:

1. Was there a search or a seizure? If not, the Fourth Amendment has nothing to say, and the analysis stops. Most of this lesson lives here.
2. Was it reasonable? Which normally means: was there a warrant based on probable cause, or does a recognised exception apply? That is the next lesson.
3. What is the remedy? Which is usually the exclusionary rule, with its own set of limits. That is the lesson after.

Two threshold limits apply throughout. The amendment restrains government action, so a purely private search, even a burglary that hands stolen documents to prosecutors, does not implicate it. And it forbids only unreasonable searches; it does not require a warrant in terms.

Key idea: Ask whether there was a search before asking whether it was reasonable, because most Fourth Amendment litigation is won and lost at the threshold.

The third-party doctrine

The most consequential consequence of Katz was not privacy protecting. If the test is what you expose, then anything you hand to somebody else is exposed.

In United States v. Miller (1976) the Court held that a bank customer has no reasonable expectation of privacy in his own cancelled checks and deposit slips, because he voluntarily conveyed them to the bank. In Smith v. Maryland (1979) it held that installing a pen register to record the numbers dialled from a home telephone was not a search, because a caller knowingly conveys those numbers to the phone company to complete the call. That is the third-party doctrine: information voluntarily disclosed to a third party carries no reasonable expectation of privacy against the government.

The doctrine was written for cancelled checks and dialled digits. Then everyone began carrying a device that continuously reports its location to a company. That collision produced the most important Fourth Amendment case of this century, which we reach below.

Where you are not protected: fields, air, garbage, and dogs

A cluster of decisions marks the outer edges of protection, and they are easier to remember as a group.

• Open fields. Land outside the curtilage is unprotected, even if fenced and posted with no trespassing signs. Hester v. United States (1924) established it and Oliver v. United States (1984) reaffirmed it: fields are not persons, houses, papers, or effects.
• Curtilage, the area immediately surrounding the home and intimately tied to its use, is protected. United States v. Dunn (1987) lists four factors: proximity to the home, whether it is enclosed with the home, how it is used, and what the resident did to shield it from observation.
• Aerial observation. Police in a fixed-wing aircraft at 1,000 feet may look into a fenced yard, California v. Ciraolo (1986), and a helicopter at 400 feet may do the same, Florida v. Riley (1989), because the public navigable airspace is a place from which anyone might look.
• Garbage. Trash left at the kerb for collection is abandoned to the public and to anyone who wants it, California v. Greenwood (1988).
• Dog sniffs. A trained dog's sniff of luggage in an airport or the exterior of a lawfully stopped car reveals only the presence of contraband, in which no one has a legitimate privacy interest, so it is not a search: United States v. Place (1983) and Illinois v. Caballes (2005). But the stop may not be extended even briefly to run the dog, Rodriguez v. United States (2015), and bringing the dog onto a front porch is a search, Florida v. Jardines (2013).

Notice the through line. The unprotected items are things you have exposed, abandoned, or placed where any member of the public might observe them. The protected ones are inside the home or its immediate surroundings.

The trespass theory comes back

For forty-five years, Katz looked like the whole test. Then the government attached a GPS tracker to the underside of Antoine Jones's Jeep and monitored it for twenty-eight days.

In United States v. Jones (2012) the Court held unanimously that this was a search, but it split badly on why. Justice Scalia's majority did not use Katz at all. It held that the government had physically occupied private property, an effect, for the purpose of obtaining information, and that this was a search when the amendment was adopted. Katz, on this view, added to the older trespass rule rather than replacing it. Concurring, Justice Alito would have used Katz and argued that long-term monitoring of every movement defeats a reasonable expectation of privacy even without a trespass. Justice Sotomayor wrote separately to question whether the third-party doctrine could survive the digital age at all.

The practical result is two tests running in parallel. A search occurs if the government physically intrudes on a constitutionally protected area to gather information, or if it violates a reasonable expectation of privacy. Jardines, the front porch dog case, was decided on the trespass ground for exactly this reason.

The upshot: Since 2012 the threshold question has two independent answers, and a defendant needs only one of them.

Technology, and the line the Court has drawn three times

Three cases show a consistent instinct: when a technology makes the government's reach categorically different rather than merely more convenient, the Court requires a warrant.

Kyllo v. United States (2001). Agents aimed a thermal imager at a home from a public street to detect the heat signature of indoor marijuana lamps. Held: where the government uses sense-enhancing technology not in general public use to obtain information about the interior of a home that could not otherwise be obtained without entry, it is a search. The home line is drawn firmly, and the general public use qualifier is doing a lot of work as technology becomes ordinary.

Riley v. California (2014). Police searched an arrestee's smartphone under the search incident to arrest exception. A unanimous Court held that phones are different in both a quantitative and qualitative sense from a wallet or a cigarette pack, holding the privacies of life; a warrant is required. The opinion is unusually direct that mechanically applying old categories to new objects produces absurd results.

Carpenter v. United States (2018). Investigating a series of robberies, the government obtained from wireless carriers 127 days of historical cell site location information for Timothy Carpenter, producing nearly thirteen thousand location points, roughly a hundred a day. Under Smith and Miller that data belonged to the carriers and was voluntarily conveyed to them. The Court held it was a search requiring a warrant, declining to extend the third-party doctrine to this category. Two features mattered: the records are a comprehensive chronicle of a person's movements, and their production is not truly voluntary, since carrying a phone is a condition of participating in modern life. The Court called the decision narrow, and it left Smith and Miller standing, so the lower courts have been sorting out its reach ever since.

Seizures, and whose rights are at stake

A seizure of property is a meaningful interference with a possessory interest. A seizure of a person occurs when, in view of all the circumstances, a reasonable person would not feel free to leave or to terminate the encounter. Two refinements matter. Under California v. Hodari D. (1991), a show of authority alone is not a seizure until the person submits, so a suspect who runs is not seized while running. Under Torres v. Madrid (2021), the application of physical force with intent to restrain is a seizure even if the person breaks free and escapes.

Finally, whose rights can be asserted? Fourth Amendment rights are personal. In Rakas v. Illinois (1978) the Court held that passengers with no possessory interest in a car or the items seized could not challenge a search of it, even though the evidence was used against them. The rule has an important counterpart: under Brendlin v. California (2007) a passenger is seized when the car is stopped, so he may challenge the lawfulness of the stop itself. Learn both, because they combine constantly in real cases: a passenger may attack the stop and lose the ability to attack the search.

In short: A defendant must show that his own expectation of privacy or possessory interest was invaded, not merely that the police behaved unlawfully toward somebody.

Common misconceptions

• The Fourth Amendment requires a warrant for every search. Its text forbids unreasonable searches; the warrant requirement is judicially developed and riddled with exceptions.
• Anything on private property is protected. Open fields are unprotected even when fenced and posted; only curtilage receives the home's protection.
• Katz means privacy is protected wherever you feel private. The expectation must be one society recognises as reasonable, which is a legal judgment, not a personal one.
• Carpenter abolished the third-party doctrine. It declined to extend it to comprehensive location records while expressly leaving Smith and Miller in place.
• Fleeing from an officer's command is a seizure. Under Hodari D. a show of authority becomes a seizure only on submission, though physical force with intent to restrain suffices under Torres.
• Any defendant can move to suppress illegally obtained evidence. Rakas requires a personal invasion of the movant's own protected interest.

What to remember

• Katz replaced the trespass-only rule with Harlan's two-part reasonable expectation of privacy test.
• Ask search or seizure first, reasonableness second, remedy third; the amendment binds government actors only.
• The third-party doctrine from Miller and Smith removes protection from information voluntarily conveyed to others.
• Open fields, aerial observation, kerbside garbage, and most dog sniffs are not searches; curtilage is protected, and Jardines shows why.
• Jones revived the trespass theory, so a search may be shown by physical intrusion or by violated expectations.
• Kyllo, Riley, and Carpenter show the Court requiring warrants when a technology changes the government's reach in kind.
• Seizure of a person turns on free to leave, with Hodari D. and Torres refining it, and Rakas limits who may complain.

Sources

1. Legal Information Institute. (n.d.). Fourth Amendment. Cornell Law School. law.cornell.edu
2. Wikipedia. (n.d.). Katz v. United States. en.wikipedia.org
3. Wikipedia. (n.d.). Carpenter v. United States. en.wikipedia.org
4. Wikipedia. (n.d.). Kyllo v. United States. en.wikipedia.org
5. Congressional Research Service. (n.d.). Constitution Annotated: Fourth Amendment. constitution.congress.gov

An anonymous letter, and the test it broke

In May 1978 the police department in Bloomingdale, Illinois, opened a handwritten letter that nobody had signed. It said that Lance and Susan Gates made their living selling drugs, that Susan would drive their car to Florida to be loaded, that Lance would fly down and drive it back, and that at that moment there was over a hundred thousand dollars worth of drugs in their basement.

The letter did not explain who the writer was or how the writer knew about the drugs. Standing alone, it did not establish probable cause. A detective checked its predictions: Lance Gates had a reservation on a flight to Florida. Agents watched him take it, saw him enter a room registered to his wife, and saw the couple start driving north the next morning. A magistrate issued a warrant, and the search turned up marijuana in the car and in the house.

The Illinois courts suppressed the evidence. They applied the two-part test developed in Aguilar v. Texas (1964) and Spinelli v. United States (1969), examining the informant's veracity and basis of knowledge. The state supreme court found the letter deficient and the corroboration inadequate. That did not mean police corroboration could never repair a deficient tip under the earlier cases; the disagreement concerned how to assess the combined information.

In Illinois v. Gates, 462 U.S. 213 (1983), the Court threw the two-pronged test away. Veracity and basis of knowledge remain relevant, Justice Rehnquist wrote, but as considerations in a single practical judgment rather than as independent hurdles. A magistrate is to ask whether, given everything in the affidavit, there is a fair probability that evidence of a crime will be found in the place to be searched. A weak showing on one factor can be made up by a strong showing on another, or by exactly what the Bloomingdale detective did: going out and confirming the tip's predictions.

Use that federal constitutional test in this lesson's warrant problems. A state constitution or statute may provide additional protection, so a federal holding does not settle every state-law question.

This is general education about United States federal Fourth Amendment doctrine, reviewed September 28, 2026, not advice about an actual encounter or case. The examples assume the stated facts and identify missing ones. State law, later decisions, and the precise circumstances may change an outcome; the source list is not a comprehensive citator check.

What probable cause is, and what it is not

Probable cause is not a percentage. In Maryland v. Pringle (2003), the Court explained that it cannot be precisely quantified and that trial standards such as preponderance or proof beyond a reasonable doubt do not govern the decision. For a search, ask whether the available facts establish a fair probability of finding evidence in the specified place. For an arrest, ask whether the facts provide an objectively reasonable ground to believe this person committed an offence. Do not turn either inquiry into a numerical cutoff.

It helps to see the ladder at once, because criminal procedure runs on the differences between these rungs.

One feature of the ladder trips students constantly. Probable cause to arrest and probable cause to search are different questions: the first asks whether this person committed an offence, the second whether evidence is in this place now. You can have one without the other.

Key idea: Probable cause is a practical, common sense judgment about probabilities, not a mathematical threshold, and the question it answers depends on whether you are arresting or searching.

Four things a warrant must have

These requirements constrain the authority to issue a valid search warrant. A defect and the remedy for that defect are separate questions.

1. A neutral and detached magistrate. In Coolidge v. New Hampshire (1971) the state attorney general, who was personally leading the investigation, signed the warrant as a justice of the peace. That was not a neutral magistrate. Johnson v. United States (1948) put the rationale plainly: the inferences should be drawn by a judicial officer rather than by the officer engaged in the competitive enterprise of ferreting out crime.
2. Oath or affirmation. The application needs sworn support, not merely an officer's unsworn assertion. Federal Rules 4.1 and 41 specify how the judge receives and records that support.
3. Probable cause presented to the issuing judge. Facts known only to the officer cannot supply the judge's missing basis. But a written affidavit is not the only permitted form: Federal Rule of Criminal Procedure 41(d)(2) allows sworn testimony, recorded and filed with the court, and Rule 41(d)(3) permits applications by telephone or other reliable electronic means under Rule 4.1.
4. Particularity. The warrant must describe the place to be searched and the persons or things to be seized. In Groh v. Ramirez (2004) the officer put a description of the house in the space for items to be seized. The application listed the items, but the warrant did not incorporate that list and the supporting papers did not accompany it. The Court held the warrant invalid. Particularity limits the search the warrant actually authorises.

Two doctrines police the edges. Under Franks v. Delaware (1978), a defendant must make a substantial preliminary showing, supported by an offer of proof, that the affiant knowingly or recklessly included a falsehood necessary to probable cause. At the resulting hearing the defendant must prove the deliberate or reckless falsity by a preponderance. If the remaining affidavit is insufficient after the false material is removed, the warrant is voided and its fruits excluded under the rule stated in Franks. Separately, Wilson v. Arkansas (1995) makes knocking and announcing part of the reasonableness inquiry, subject to circumstances such as danger or likely evidence destruction. Hudson v. Michigan (2006) holds that violating that requirement does not itself require exclusion of evidence found while executing the search warrant.

The exceptions, laid out together

Courts recite that warrantless searches are per se unreasonable subject only to a few specifically established and well delineated exceptions. Count them and few looks generous.

Three repay a closer look.

Gant, Collins, and Lange: three trims

Arizona v. Gant (2009). Rodney Gant was arrested for driving with a suspended licence, handcuffed, and locked in a patrol car. Officers then searched his car and found cocaine in a jacket pocket. Many courts had read New York v. Belton (1981) to allow a passenger-compartment search whenever a recent occupant was arrested. Gant rejected that reading. Incident to a recent occupant's lawful arrest, officers may search the passenger compartment and containers there if the arrestee is unsecured and within reaching distance of that compartment at the time of the search, or if it is reasonable to believe evidence of the offence of arrest might be found in the vehicle. Securing Gant defeated the access route. His licence offence supplied no reasonable basis to expect relevant evidence in the car, defeating the separate evidence route.

Now change one fact. Suppose the recent occupant was lawfully arrested for an offence for which officers reasonably believe relevant evidence is in the passenger compartment. Securing that person does not eliminate Gant's evidence route. Mere speculation that something might be inside is insufficient. Nor does Gant authorise a search of the boot, or trunk. A separate automobile-exception analysis under United States v. Ross can reach the trunk if probable cause supports looking there for the object sought, including evidence of a different offence. Keep the two doctrines separate.

Collins v. Virginia (2018). An officer walked up a driveway, lifted a tarpaulin off a motorcycle parked beside the house, and read its identification number. The automobile exception covers vehicles, the state argued. The Court answered that it does not license entry onto the curtilage of a home to reach one. An exception does not dissolve another protection on contact.

Lange v. California (2021). An officer activated his lights about a hundred feet before a driver reached home, then followed him into the attached garage. The lower court treated pursuit of a fleeing misdemeanant as automatically sufficient. The Supreme Court required a case-specific assessment of the need to act before obtaining a warrant, including risks of injury, escape, or evidence destruction. In Kentucky v. King (2011), the Court held that police do not impermissibly create an exigency merely by lawful knocking and announcing: the relevant question is whether they violated or threatened to violate the Fourth Amendment before the exigency arose. It assumed an exigency for argument and left whether one actually existed for remand. Hearing movement is not automatically proof of imminent destruction. Missouri v. McNeely (2013) similarly rejected a categorical rule that alcohol's natural dissipation always excuses a warrant for a blood draw.

Emergency aid answers a different question from evidence gathering. In Case v. Montana (January 14, 2026), the Court reaffirmed that officers need an objectively reasonable basis to believe an occupant is seriously injured or imminently threatened with serious injury. It rejected adding a criminal probable-cause test to that inquiry and did not equate the standard with the reasonable suspicion used for street stops. The entry and its manner must fit the aid purpose. A generic welfare concern does not by itself establish the required emergency.

What matters here: Check every available route and its limits. Securing an arrestee defeats Gant's access route, but its offence-evidence route requires a separate decision. Likewise, a lawful knock does not by itself prove an exigency.

Consent: voluntariness, authority, and scope

Schneckloth v. Bustamonte (1973) addressed consent by a person not in custody. The prosecution had to show voluntary permission under all the circumstances, without express or implied coercion. Knowledge of the right to refuse mattered, but the prosecution did not have to prove such knowledge as a prerequisite. Thus, failure to give a refusal warning does not alone invalidate consent; it does not establish voluntariness either.

Whose consent counts? Under United States v. Matlock (1974), a third party with common authority over the premises may consent, because co-inhabitants assume the risk that one of them will let someone in. Under Illinois v. Rodriguez (1990) it is enough that the officers reasonably believed the consenter had authority, even if she did not. But under Georgia v. Randolph (2006), when one occupant is physically present and expressly refuses, another occupant's consent does not override the refusal. And Fernandez v. California (2014) narrowed that: once the objecting occupant has been lawfully removed, the remaining occupant may consent.

Read those four together and ask three separate questions. Was the permission voluntary? Did the person have common authority over the area searched, or did the known facts reasonably establish apparent authority? Did the search stay within what a reasonable person would understand the permission to cover? Florida v. Jimeno (1991) supplies that scope test. A co-occupant's consent is not permission to search every other resident's private space or belongings. The Randolph objection rule concerns a consent-based evidentiary search as against the present objector; it does not bar an independently justified emergency entry.

Terry, and the stop that is not an arrest

In October 1963 a Cleveland detective named Martin McFadden watched two men take turns walking past a shop window, peering in, and returning to confer. Suspecting a robbery was being cased, he approached them, patted down the outside of their coats, and found guns. The courts did not find probable cause to arrest them before that frisk; the question was whether the more limited intrusion was justified.

Terry v. Ohio, 392 U.S. 1 (1968), held that the forcible stop was a seizure and the pat down a search, but both could be reasonable on less than probable cause. The officer needs specific and articulable facts, plus rational inferences, supporting suspicion of criminal activity. The frisk separately requires a reasonable belief that the person is armed and dangerous. It is a limited search for weapons, ordinarily beginning with the outer clothing. In Terry the officer reached inside only after feeling guns; the doctrine does not forbid removing a suspected weapon, but it does forbid an unrestricted search for evidence.

The refinements that matter:

• Plain feel. Minnesota v. Dickerson (1993): if the incriminating character of an object is immediately apparent from the lawful pat down, it may be seized; but the officer in that case had to squeeze and manipulate a lump to work out what it was, which exceeded the frisk.
• Flight. Illinois v. Wardlow (2000) found reasonable suspicion from unprovoked headlong flight in an area known for heavy narcotics trafficking. Presence in such an area alone is insufficient. Flight is assessed in context, not through a universal rule that it always, or never, suffices by itself.
• Anonymous tips. Florida v. J.L. (2000) rejected a bare anonymous gun tip that lacked reliable support for its allegation of illegality. Identifying a person and location was insufficient. Navarette v. California (2014) upheld a stop based on a reported road incident, considering the claimed eyewitness knowledge, prompt report, 911 safeguards, and conduct suggesting drunk driving. It did not declare every 911 call reliable.
• Identification. Hiibel v. Sixth Judicial District Court (2004) upheld Nevada's name-disclosure requirement during a valid Terry stop. The requirement had to relate to the stop's purpose; the Court also reserved a possible Fifth Amendment issue where giving a name would create a reasonable danger of incrimination. It did not establish a nationwide duty to produce an identity document.

In short: A Terry stop trades a lower threshold for a narrower intrusion, and the frisk is a weapons search, not an evidence search.

Whren, and the question the Court refused to ask

Plainclothes vice officers in an unmarked car in Washington, D.C. watched a truck wait at a stop sign an unusually long time and then turn without signalling and speed away. They stopped it for the traffic violations and saw crack cocaine in passenger Michael Whren's hands. The defendants argued that reasonable officers patrolling vice would not have made that traffic stop, so the offences were a pretext.

Whren v. United States, 517 U.S. 806 (1996), rejected that challenge unanimously. The officers' subjective motive did not invalidate the ordinary traffic stop supported by probable cause. The Court separately recognised that intentionally discriminatory enforcement based on race violates equal protection. Its Fourth Amendment holding does not authorise racial selection, an unreasonable manner of seizure, or every action following a valid stop.

Atwater v. City of Lago Vista (2001) upheld a custodial arrest for fine-only seatbelt misdemeanours committed in the officer's presence and supported by probable cause. That federal holding did not require arrest or remove stricter state limits, and the Court separately considered whether the arrest was conducted in an extraordinary, unusually harmful manner.

Purpose has a different role in suspicionless checkpoint programmes. Michigan Department of State Police v. Sitz (1990) upheld the sobriety programme before it. City of Indianapolis v. Edmond (2000) rejected checkpoints primarily aimed at finding ordinary criminal wrongdoing, specifically drug offences. Illinois v. Lidster (2004) upheld brief stops seeking public help about a fatal hit and run a week earlier, rather than investigating each stopped driver. A permissible purpose does not end the analysis: courts also consider the public concern, how the seizure advances it, and the interference with liberty. These decisions concern the programmes and facts reviewed, not blanket permission for any roadblock with a public-safety label.

Common misconceptions

• Probable cause means more than fifty per cent. The Court has declined to quantify it. Apply the contextual legal test instead of assigning a percentage.
• Anonymous tips cannot support a search. Gates says they can, when corroboration or other indicia make the totality sufficient.
• If police do not tell you that you may refuse, your consent is invalid. Schneckloth holds the opposite; the warning is a factor, not a prerequisite.
• An arrest lets police search the whole car. Gant requires one of its two routes and concerns the passenger compartment and containers there. A trunk search needs a different justification, such as the automobile exception, with that doctrine's own conditions.
• A frisk lets an officer look for drugs. The frisk is justified by officer safety and is limited to weapons, subject to the narrow plain feel rule.
• A hidden investigative motive invalidates a traffic stop. Whren rejects that argument against an ordinary stop supported by probable cause. Intentionally racial enforcement remains an equal-protection issue, and other limits on the seizure still apply.

Recap

• Gates replaced the rigid Aguilar and Spinelli prongs with a totality of the circumstances test asking for a fair probability.
• A valid search warrant needs a neutral magistrate, sworn support establishing probable cause, and particularity. Federal procedures allow recorded sworn testimony, not only affidavits; Franks supplies a test for material deliberate or reckless affidavit falsehoods.
• The warrant requirement is surrounded by exceptions, each defined by the justification that created it, and Gant, Collins, and Lange show the Court refusing to let one outrun its rationale.
• Consent requires voluntariness, actual or reasonably apparent authority, and a search within the permission's scope. Absence of a refusal warning alone does not decide voluntariness.
• Terry separates suspicion of criminal activity from the reasonable belief that a person is armed and dangerous needed for a weapons frisk.
• Whren rejects a motive challenge to an ordinary traffic stop supported by probable cause. Checkpoint analysis examines programme purpose and the reasonableness of the intrusion.

Sources

1. Supreme Court of the United States. (1983). Illinois v. Gates, 462 U.S. 213, pp. 225-246. Primary opinion reproduction
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3. Supreme Court of the United States. (1971). Coolidge v. New Hampshire, 403 U.S. 443, pp. 449-453. Primary opinion reproduction
4. Supreme Court of the United States. (1948). Johnson v. United States, 333 U.S. 10, pp. 13-14. Primary opinion reproduction
5. Supreme Court of the United States. (2004). Groh v. Ramirez, 540 U.S. 551, pp. 554-558. Primary opinion reproduction
6. Supreme Court of the United States. (1978). Franks v. Delaware, 438 U.S. 154, pp. 155-156, 171-172. Primary opinion reproduction
7. Supreme Court of the United States. (1995). Wilson v. Arkansas, 514 U.S. 927, pp. 934-936. Primary opinion reproduction
8. Supreme Court of the United States. (2006). Hudson v. Michigan, 547 U.S. 586, pp. 590-594. Primary opinion reproduction
9. Supreme Court of the United States. (2009). Arizona v. Gant, 556 U.S. 332, pp. 343-347. Primary opinion reproduction
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11. Supreme Court of the United States. (1982). United States v. Ross, 456 U.S. 798, pp. 820-825. Primary opinion reproduction
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13. Supreme Court of the United States. (2011). Kentucky v. King, 563 U.S. 452, pp. 460-462, 469-473. Primary opinion reproduction
14. Supreme Court of the United States. (2013). Missouri v. McNeely, 569 U.S. 141, pp. 145, 151-156. Primary opinion reproduction
15. Supreme Court of the United States. (1973). Schneckloth v. Bustamonte, 412 U.S. 218, pp. 227, 248-249 and n. 38. Primary opinion reproduction
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17. Supreme Court of the United States. (1990). Illinois v. Rodriguez, 497 U.S. 177, pp. 188-189. Primary opinion reproduction
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19. Supreme Court of the United States. (2014). Fernandez v. California, 571 U.S. 292, pp. 300-306, opinion Parts II-III. Primary opinion reproduction
20. Supreme Court of the United States. (1991). Florida v. Jimeno, 500 U.S. 248, pp. 250-252. Primary opinion reproduction
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22. Supreme Court of the United States. (1993). Minnesota v. Dickerson, 508 U.S. 366, pp. 375-379. Primary opinion reproduction
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Three officers, a piece of paper, and a trunk in the basement

In May 1957 three Cleveland police officers came to Dollree Mapp's house looking for a man wanted for questioning about a bombing. She telephoned her lawyer and refused to let them in without a warrant. They waited. Hours later more officers arrived, forced a door, and when Mapp demanded to see the warrant one of them held up a piece of paper. She grabbed it and put it inside her blouse. An officer retrieved it by reaching in. No warrant was ever produced at trial, and no witness ever explained what the paper was.

The officers did not find the bombing suspect. In a trunk in the basement they found books and photographs, and Ohio convicted Mapp of knowingly possessing obscene material. Her sentence was one to seven years.

Everyone agreed the search was unlawful. The question in Mapp v. Ohio, 367 U.S. 643 (1961), was what follows from that. And the answer the Court gave, that unlawfully obtained evidence may not be used in a state criminal trial, is the most consequential and the most contested remedy in American criminal procedure. It is worth being clear at the outset that reasonable and well informed people disagree about it, and that the Supreme Court itself has spent sixty years steadily narrowing what it announced.

Weeks, Wolf, and the forty-seven years in between

The Fourth Amendment says what the government may not do. It says nothing about what happens if the government does it anyway. For most of American history the answer was: nothing much. The evidence came in, and the person whose door was broken could sue in trespass, which meant suing an officer with no money before a jury unlikely to care.

Weeks v. United States, 232 U.S. 383 (1914), created the remedy for federal cases. Federal marshals had searched Fremont Weeks's house twice without a warrant. A unanimous Court held that the papers had to be returned and could not be used against him, reasoning that if letters seized in violation of the amendment could be held and used in evidence, the protection was of no value.

But Weeks bound only the federal government, and until 1949 the Fourth Amendment itself did not apply to the states. Wolf v. Colorado (1949) took the first half of the step and refused the second: the core of the Fourth Amendment is enforceable against the states through the Fourteenth Amendment's due process clause, but the exclusionary rule is not required, because states might devise other remedies. For twelve years that left an odd arrangement in which state police could seize evidence unlawfully and hand it to federal prosecutors, a practice known as the silver platter doctrine, ended in Elkins v. United States (1960).

Mapp overruled the remedial half of Wolf. Justice Clark's opinion gave two reasons. The first was deterrence: without exclusion, the constitutional right is a form of words. The second was judicial integrity, the idea that courts should not be receivers of stolen goods, or, in Justice Brandeis's older phrase from his Olmstead dissent, that the government should not become a lawbreaker to catch lawbreakers. Hold on to the fact that Mapp gave two rationales, because the Court has since discarded one of them.

Remember: Exclusion is a judicially created remedy, not a right the amendment names. Everything the Court has done since 1961 follows from that classification.

Fruit of the poisonous tree

Suppressing the thing seized is only the start. Suppose an unlawful search of an office turns up a ledger, and the ledger names a supplier, and the supplier testifies. Is the testimony in?

Silverthorne Lumber Co. v. United States (1920) supplied the principle. Federal agents unlawfully seized company books, photographed them, and after being ordered to return them tried to subpoena the same documents. Justice Holmes wrote that the essence of forbidding the acquisition of evidence in a certain way is that it shall not be used at all, and that knowledge gained by the government's own wrong may not be used in this way. The phrase fruit of the poisonous tree came later, from Justice Frankfurter in Nardone v. United States (1939).

Wong Sun v. United States (1963) gave the test its modern shape and, more usefully, gave it a limit. The question is not simply whether the evidence would have come to light but for the illegality. It is whether the evidence was come at by exploitation of the illegality, or instead by means sufficiently distinguishable to be purged of the primary taint. That sentence is doing all the work in the three doctrines below.

Three ways the fruit gets in anyway

Independent source. If the evidence was in fact obtained through a lawful route that did not depend on the illegal one, it is admissible. In Murray v. United States (1988) agents unlawfully entered a warehouse, saw bales of marijuana, left, and obtained a warrant without mentioning what they had seen and without relying on it. The Court held that if the later warrant was genuinely independent, meaning the decision to seek it was not prompted by what they saw and the affidavit did not include it, the evidence comes in.

Inevitable discovery. If the evidence would inevitably have been found by lawful means, the prosecution may show that by a preponderance of the evidence. Nix v. Williams (1984) is the case: a defendant's unlawfully obtained statements led police to a child's body, but a search party of two hundred volunteers was already working a grid that would have reached the location within hours. Note the difference from independent source. Independent source asks what the police actually did; inevitable discovery asks what they would have done.

Attenuation. Time, intervening events, and the flagrancy of the misconduct can break the chain. Brown v. Illinois (1975) lists the factors: how much time passed, whether there were intervening circumstances, and, importantly, the purpose and flagrancy of the official misconduct.

Utah v. Strieff (2016) shows how much that doctrine can carry. An officer conducting surveillance on a suspected drug house stopped Edward Strieff after he left it. The stop was conceded to be unlawful. The officer ran his name, found an outstanding traffic warrant, arrested him on it, searched him incident to the arrest, and found methamphetamine. The Court held the evidence admissible: the valid pre-existing warrant was an intervening circumstance, and the officer's error was at most negligent rather than flagrant. Justice Sotomayor's dissent argued that in jurisdictions with very large numbers of outstanding minor warrants the holding gives police a reason to make unlawful stops and then check for a warrant.

Leon, and the turn to deterrence

In United States v. Calandra (1974) the Court described the rule as a judicially created remedy designed to safeguard Fourth Amendment rights generally through its deterrent effect, rather than a personal constitutional right of the party aggrieved. Once that is the premise, the analysis becomes a cost-benefit question: exclude only where exclusion will actually deter police.

United States v. Leon, 468 U.S. 897 (1984), drew the conclusion. Officers obtained a warrant that a magistrate issued and a reviewing court later found unsupported by probable cause. The Court held the evidence admissible, because suppressing it would punish the officers for the magistrate's error and would deter nothing. That is the good faith exception: evidence obtained in objectively reasonable reliance on a warrant later held invalid is not suppressed.

Leon named four situations where reliance is not reasonable, and they are worth memorising because they are where a defendant still wins: the affiant lied or was reckless with the truth, the magistrate wholly abandoned his judicial role, the affidavit was so lacking in indicia of probable cause that belief in it was unreasonable, and the warrant was so facially deficient that no officer could reasonably presume it valid.

The core of it: After Leon, the question stopped being whether the search was lawful and became whether suppressing this evidence would change future police behaviour.

Herring and Davis: how far negligence goes

The good faith idea then travelled beyond warrants. Illinois v. Krull (1987) applied it to reliance on a statute later held unconstitutional. Arizona v. Evans (1995) applied it to a court clerk's database error. Herring v. United States (2009) applied it to an error by police employees themselves: a neighbouring county's warrant database wrongly showed an active warrant that had been recalled months earlier. Chief Justice Roberts wrote that to trigger the rule, police conduct must be sufficiently deliberate that exclusion can meaningfully deter it and sufficiently culpable that deterrence is worth the price. Isolated negligence attenuated from the search does not qualify. Davis v. United States (2011) added reliance on binding appellate precedent that is later overruled, which is how the officers in the post-Gant cases kept their evidence.

Read the sequence and you can see the trajectory. In 1961 the rule applied to unlawful searches. By 2009 it applied to unlawful searches carried out deliberately, recklessly, or with gross or systemic negligence.

Where the rule does not apply at all

• Grand jury proceedings. A witness may not refuse to answer questions based on unlawfully obtained evidence: Calandra.
• Impeachment. A defendant who testifies may be confronted with suppressed evidence to contradict him: Walder v. United States (1954) and United States v. Havens (1980). The rule is a shield, not a licence to lie.
• Parole and probation revocation. Pennsylvania Board of Probation and Parole v. Scott (1998).
• Knock and announce violations. Hudson v. Michigan (2006): the interests protected by the knock rule, such as avoiding property damage and preserving dignity, have nothing to do with the seizure of the evidence, so suppression is not the remedy.
• Civil, immigration, and most administrative proceedings.
• Anyone but the person whose rights were violated. This is the standing point from Rakas in the previous lesson.

The argument, and what would settle it

Here are the two positions in their strongest form, which is the only way to judge them.

The case against. Exclusion punishes the public rather than the officer. The officer keeps his job and his salary; the person who suffers is the victim of the crime whose case collapses. It is also badly targeted: it does nothing for the innocent person whose home is wrongly searched, because there is no prosecution in which to suppress anything, and it rewards only the guilty, in rough proportion to how much evidence the police found. Chief Justice Burger, dissenting in Bivens in 1971, urged replacing it with a statutory damages scheme. Judge Henry Friendly made the same argument in the academic literature. Other common law countries manage with discretionary exclusion: in Canada, section 24(2) of the Charter directs a court to exclude only where admission would bring the administration of justice into disrepute, and English law under the Police and Criminal Evidence Act 1984 gives the trial judge a discretion rather than a rule.

The case for. The alternatives do not work, and this is an empirical claim rather than a slogan. Damages actions under 42 U.S.C. section 1983 and, against federal officers, under Bivens v. Six Unknown Named Agents (1971), run into qualified immunity, which protects officials unless they violated clearly established law, and the Court has spent two decades declining to extend Bivens to new contexts, most recently in Egbert v. Boule (2022). Internal discipline is administered by the same institution being deterred. Meanwhile the measured costs of exclusion are small: reviewing the available studies for the American Bar Foundation in 1983, Thomas Davies found that the cumulative loss of felony arrests attributable to illegal searches was on the order of one to two per cent, concentrated almost entirely in drug and weapons cases. And there is direct evidence of the rule changing behaviour, since police departments across the country wrote warrant procedures, training programmes, and legal advice into their operations after 1961 in a way they had not before.

What would settle it. The honest answer is that the central question is very hard to measure. To know whether exclusion deters, you would need to observe searches that were never made because an officer expected suppression, and unmade searches leave no record. Suppression motion rates measure the visible tail of police conduct, not the invisible part the rule is supposed to shape. A convincing study would need something close to a natural experiment: a jurisdiction where the remedy changed sharply while everything else held constant, with measurement of search quality rather than case outcomes. Mapp itself was such a moment for the twenty-odd states that had no exclusionary rule in 1961, which is why the studies of that period remain the most cited evidence on both sides.

Bottom line: Whether you think the rule is worth its costs depends less on the Fourth Amendment than on how much you believe the alternatives could be made to work.

Common misconceptions

• Illegally obtained evidence is always thrown out. Good faith, independent source, inevitable discovery, and attenuation each let it in, and several proceedings are outside the rule entirely.
• The exclusionary rule is in the Fourth Amendment. The amendment provides no remedy; exclusion is judge-made, which is why the Court can and does adjust it.
• If the police broke the rules, the case gets dismissed. Suppression removes evidence. The prosecution may proceed on whatever is left, and often does.
• Good faith means the officer meant well. The test is objective reasonableness, not sincerity, and Leon lists four situations where reliance is unreasonable however honest.
• Mapp settled the question. The Court has narrowed the rule repeatedly since 1974 by treating deterrence as its only justification.
• Suppressed evidence can never be mentioned at trial. Under Havens it may be used to impeach a defendant who takes the stand and contradicts it.

Where this leaves us

• Weeks created the federal rule in 1914; Wolf applied the amendment to the states without the remedy; Mapp supplied the remedy in 1961.
• Fruit of the poisonous tree extends suppression to derivative evidence, subject to Wong Sun's exploitation and purged taint test.
• Independent source asks what police actually did; inevitable discovery asks what they would have done; attenuation weighs time, intervening events, and flagrancy.
• Leon created the good faith exception and listed four circumstances in which reliance on a warrant is still unreasonable.
• Herring and Davis extended good faith to police negligence and to reliance on later overruled precedent.
• The rule does not reach grand juries, impeachment, revocation hearings, knock and announce violations, or defendants without standing.
• The dispute is empirical: whether exclusion deters, and whether damages actions could be made to work instead.

Sources

1. Legal Information Institute. (n.d.). Exclusionary rule. Cornell Law School. law.cornell.edu
2. Wikipedia. (n.d.). Mapp v. Ohio. en.wikipedia.org
3. Wikipedia. (n.d.). United States v. Leon. en.wikipedia.org
4. Congressional Research Service. (n.d.). Constitution Annotated: Fourth Amendment. constitution.congress.gov
5. Davies, T. Y. (1983). A hard look at what we know (and still need to learn) about the costs of the exclusionary rule. American Bar Foundation Research Journal, 1983(3).

Kemper County, Mississippi, 1934

Raymond Stewart was killed on March 30, 1934. Officers and other men tortured three Black defendants into confessing. Yank Ellington continued to deny involvement after being hanged twice and whipped; he confessed after a later arrest and further whipping. Ed Brown and Henry Shields were beaten until their accounts matched what their interrogators demanded. Their trial began on April 5 and ended the next day with death sentences.

In Brown v. Mississippi (1936), the Supreme Court reversed convictions resting on those coerced confessions. The question was whether the state could use torture to secure a conviction. Reading warnings would not have cured that abuse. Start there when analysing a confession: the method of obtaining it matters independently of the warning.

Voluntariness remains a separate question

The due process test asks whether official coercion overbore the person's will, considering the circumstances together. Relevant facts include threats, deprivation of sleep, the length and conditions of questioning, and the person's ability to understand and resist pressure. A signed form is evidence to consider; it does not settle what happened before the signature.

Colorado v. Connelly (1986) sets an important boundary. Mental illness alone does not establish that a confession was involuntary under the Due Process Clause: coercive police activity is necessary. That constitutional threshold does not prove that a statement is accurate. Reliability, voluntariness and a valid waiver of rights answer different questions.

The point: Analyse voluntariness and Miranda separately. A voluntary statement can be excluded because required safeguards were missing. A warned statement can still be involuntary because of coercion.

What the warnings protect

Miranda v. Arizona (1966) requires safeguards before custodial interrogation. A suspect must be informed of the right to silence, that statements can be used against the suspect, the right to consult a lawyer and have that lawyer present during questioning, and the right to appointed counsel before questioning if unable to afford counsel and wanting that help.

The prosecution generally cannot use statements obtained without the required warnings and valid waiver in its case in chief, meaning the evidence it presents to establish guilt. Suppression of a statement does not automatically dismiss a charge. Other admissible evidence may remain. Exceptions and permitted uses must be examined individually.

First ask whether the person was in custody

Custody means formal arrest or restrictions comparable to arrest, assessed objectively in the circumstances. Being questioned at a station is not enough by itself. Nor does every situation in which someone cannot immediately leave count as Miranda custody.

In Berkemer v. McCarty (1984), an ordinary roadside traffic stop did not count because its temporary, public character differed from arrest-like detention. A stop can become custodial if the treatment changes. Compare a brief question at a car window with questioning after arrest: the location might remain the same while the degree of restraint changes.

J. D. B. v. North Carolina (2011) requires considering a child's age when officers know it or it is objectively apparent. The Court sent the case back for the custody inquiry with age included. It did not hold that every interview at school is custodial. Ask what the setting and instructions would communicate to a reasonable child of that age.

Then ask whether there was interrogation

Direct questions are not the only way to seek a response. Under Rhode Island v. Innis (1980), interrogation also includes police words or actions, apart from those normally associated with arrest and custody, that officers should know are reasonably likely to produce an incriminating response. Their knowledge of a suspect's particular vulnerability can matter.

In Innis, officers transporting the suspect discussed the danger if a child found a missing shotgun. The Court found their brief remarks insufficient under this test, including because the record did not show awareness that this particular appeal would affect him. His actual response did not retroactively make every preceding remark interrogation.

For a contrasting hypothetical, suppose officers know a suspect is distressed about his mother's arrest and repeatedly suggest that confessing will spare her. Examine what the officers should anticipate in that setting. The absence of a question mark does not end the analysis.

New York v. Quarles (1984) recognises a limited public safety exception. Officers found an empty holster on a handcuffed suspect in a supermarket and asked where the gun was. The missing weapon created a danger that reasonably prompted the question. The test does not depend on proving that the officer lacked an evidence-gathering motive. Questions extending beyond the safety need require a separate analysis.

Waiver requires understanding as well as an answer

A waiver gives up the exercise of a right for the questioning at issue. It must be voluntary, knowing and intelligent. Berghuis v. Thompkins (2010) allows an implied waiver when warnings were given, the suspect understood them, and the suspect then made an uncoerced statement without invoking the right. A signed waiver is not indispensable, but a response alone does not prove understanding.

Thompkins said very little during nearly three hours of questioning, then gave an incriminating answer. The Court held that his silence did not clearly invoke his right to cut off questioning. Keep the two inquiries separate: was there a clear invocation, and did the prosecution establish a valid waiver? Failure to invoke does not dispense with the second inquiry.

Davis v. United States (1994) concerned an ambiguous reference to counsel after a valid waiver. The Court did not require officers to stop or ask a clarifying question when the suspect merely suggested that perhaps he should speak with a lawyer. A clear request is different.

What changes after a clear invocation

Under Edwards v. Arizona (1981), police generally cannot restart custodial interrogation after a clear request for counsel without counsel present. Arizona v. Roberson (1988) extends this protection across offences. A different detective or a different accusation does not by itself remove it.

Two qualifications matter. The suspect may initiate further discussion, but that initiation is not itself a waiver; any subsequent interrogation still requires a valid waiver. Under Maryland v. Shatzer (2010), a break of at least fourteen days in Miranda custody ends the Edwards presumption. Police must still satisfy the ordinary warning and waiver requirements when custodial interrogation resumes.

Invoking silence has a different rule. Michigan v. Mosley (1975) asks whether police scrupulously honoured the person's choice to stop. Mosley allowed later questioning after immediate cessation, a substantial interval, fresh warnings and questioning about a different crime. It did not create permission to keep asking until the person gives in.

Match the remedy to the violation

• Impeachment. Harris v. New York (1971) permits an otherwise legally trustworthy, voluntary statement obtained without full Miranda safeguards to challenge the defendant's inconsistent trial testimony. This is different from using it in the prosecution's case in chief.
• Physical evidence. United States v. Patane (2004) permits physical evidence derived from an unwarned but voluntary statement despite the warning failure. It does not excuse an independent unlawful search or actual coercion.
• A later confession. Oregon v. Elstad (1985) rejects automatic exclusion of a later properly warned and voluntary statement just because an earlier voluntary admission was unwarned. The later waiver and circumstances still need assessment.
• A deliberate two-step interview. Missouri v. Seibert (2004) excluded a repeated confession obtained through a deliberate question-first, warn-later strategy. The opinions differed: the plurality examined warning effectiveness, while Justice Kennedy's narrower concurrence focused on deliberate evasion and adequate curative measures. Simply reading the warning between two connected rounds did not cure that interview.
• Civil damages. Vega v. Tekoh (2022) holds that a Miranda violation alone does not support a damages claim under 42 U.S.C. section 1983. It does not decide every possible claim arising from separately unconstitutional conduct.

Dickerson v. United States (2000) held that Congress could not replace Miranda with a statute making voluntariness the sole admissibility test. Read that alongside Vega: the continuing force of the warning rule and the availability of a civil remedy are distinct questions.

The Sixth Amendment begins at a different point

The Sixth Amendment right attaches when adversary judicial criminal proceedings begin. Rothgery v. Gillespie County (2008), page 198, lists formal charge, preliminary hearing, indictment, information and arraignment as ways proceedings can begin. Its qualifying initial appearance involved notice of the accusation and a restriction on liberty. A prosecutor need not participate. Neither custody alone nor the label first appearance supplies the whole test.

Attachment also differs from a critical stage, a proceeding at which the need for counsel's assistance requires counsel's presence unless validly waived. Rothgery requires timely appointment for an eligible person requesting counsel so that representation is available at critical stages. It did not hold that the attachment hearing itself is always a critical stage.

Texas v. Cobb (2001) uses the Blockburger test: compare the statutory elements and ask whether each offence requires a fact the other does not. An uncharged offence can fall within the protection if it is the same offence under that test. Sharing the same incident, by itself, is insufficient.

In Massiah v. United States (1964), agents deliberately obtained statements after indictment through a cooperating defendant while the accused was on bail. The Sixth Amendment applied despite the absence of custody. By contrast, Illinois v. Perkins (1990) allowed voluntary statements to an undercover agent believed to be a fellow inmate without Miranda warnings. After attachment, that same method of eliciting statements about the covered offence raises the separate Massiah issue.

The Sixth Amendment right can be waived. Montejo v. Louisiana (2009) overruled a rule automatically invalidating certain police-initiated waivers after counsel was requested at a judicial proceeding. A voluntary, knowing and intelligent waiver remains possible after attachment or appointment. A separate Miranda counsel invocation must still be analysed under Edwards.

Appointment and effective assistance

Gideon v. Wainwright (1963) requires appointed counsel for an indigent defendant in a state felony prosecution unless the right is validly waived. For misdemeanours, actual imprisonment cannot be imposed following an uncounselled prosecution without a valid waiver. Alabama v. Shelton (2002) includes a suspended prison sentence that could later be activated. These rules concern entitlement to representation, not a new moment of attachment at sentencing.

Strickland v. Washington (1984) generally requires two showings for an ineffective-assistance claim: professionally unreasonable performance and a reasonable probability of a different result without the error. Courts assess counsel's choices in their circumstances, with a strong presumption of reasonable professional assistance. Prejudice means enough doubt to undermine confidence in the outcome, not proof that a different result was more likely than not. Losing the case alone proves neither part.

Legal admissibility does not guarantee reliability

Frazier v. Cupp (1969) treated a false claim about an accomplice's statement as one factor in the total circumstances and upheld that confession. It did not authorise every deception in every setting. State rules can supply additional protection, so a federal holding is not a complete instruction manual for an actual interview.

Kassin and colleagues' 2025 scientific review updates their 2010 account of false confessions. It identifies risks associated with prolonged and confrontational questioning, false evidence, implied leniency, youth and some cognitive or mental-health vulnerabilities. These are risk factors, not a diagnosis of whether a particular confession is false. The authors recommend recording entire interviews from a neutral camera angle, among other safeguards.

A full recording can reveal the questions and pressures leading to an admission; a recording of only the final statement cannot show that earlier interaction. Recording provides evidence for scrutiny. It does not guarantee accuracy or make coercion lawful.

Common misconceptions

• Arrest alone requires warnings. Miranda ordinarily concerns custodial interrogation, not custody without questioning.
• Answering proves waiver. The prosecution must also establish understanding and voluntariness.
• A warning failure destroys the whole case. Identify the statement, its proposed use and any separate violation before deciding the remedy.
• Every first appearance creates the Sixth Amendment right for the first time. Proceedings may already have begun through indictment or another qualifying step.
• Having counsel prevents every later police approach. Attachment, invocation, waiver and the offence being investigated must each be considered.

What to carry forward

Work through an interview in order: coercion, custody, interrogation, warnings, understanding, waiver and any invocation. Then ask whether adversary proceedings had begun and whether agents elicited statements about an offence covered by the Sixth Amendment. Finally identify the evidence and the use being challenged. This sequence explains why the same conversation may raise more than one right and why their remedies differ.

Remember: The reviewed federal rules provide a foundation for study. State law and particular procedural settings may provide additional protections. Sources were inspected on September 28, 2026; this selected review is not a comprehensive current-law or case-specific assessment.

Sources

1. Supreme Court of the United States. (1936). Brown v. Mississippi. 297 U.S. 278, pp. 279-287. Opinion text
2. Supreme Court of the United States. (1986). Colorado v. Connelly. 479 U.S. 157, pp. 163-167. Opinion text
3. Supreme Court of the United States. (1966). Miranda v. Arizona. 384 U.S. 436, pp. 467-479. Opinion text
4. Supreme Court of the United States. (1984). Berkemer v. McCarty. 468 U.S. 420, pp. 436-442. Opinion text
5. Supreme Court of the United States. (2011). J. D. B. v. North Carolina. 564 U.S. 261, pp. 271-281. Opinion text
6. Supreme Court of the United States. (1980). Rhode Island v. Innis. 446 U.S. 291, pp. 300-303. Opinion text
7. Supreme Court of the United States. (1984). New York v. Quarles. 467 U.S. 649, pp. 655-659. Opinion text
8. Supreme Court of the United States. (2010). Berghuis v. Thompkins. 560 U.S. 370, pp. 381-387. Opinion text
9. Supreme Court of the United States. (1994). Davis v. United States. 512 U.S. 452, pp. 458-462. Opinion text
10. Supreme Court of the United States. (1981). Edwards v. Arizona. 451 U.S. 477, pp. 484-486. Opinion text
11. Supreme Court of the United States. (2010). Maryland v. Shatzer. 559 U.S. 98, pp. 104-117. Opinion text
12. Supreme Court of the United States. (1975). Michigan v. Mosley. 423 U.S. 96, pp. 103-106. Opinion text
13. Supreme Court of the United States. (1971). Harris v. New York. 401 U.S. 222, pp. 224-226. Opinion text
14. Supreme Court of the United States. (1985). Oregon v. Elstad. 470 U.S. 298, pp. 309-318. Opinion text
15. Supreme Court of the United States. (2004). Missouri v. Seibert. 542 U.S. 600, pp. 615-617, 618-622. Opinion text
16. Supreme Court of the United States. (2000). Dickerson v. United States. 530 U.S. 428, pp. 432, 438-444. Opinion text
17. Supreme Court of the United States. (2001). Texas v. Cobb. 532 U.S. 162, pp. 172-174. Opinion text
18. Supreme Court of the United States. (1964). Massiah v. United States. 377 U.S. 201, pp. 204-207. Opinion text
19. Supreme Court of the United States. (2009). Montejo v. Louisiana. 556 U.S. 778, pp. 786-797. Opinion text
20. Supreme Court of the United States. (1990). Illinois v. Perkins. 496 U.S. 292, pp. 296-300. Opinion text
21. Supreme Court of the United States. (1963). Gideon v. Wainwright. 372 U.S. 335, pp. 339-345. Opinion text
22. Supreme Court of the United States. (2002). Alabama v. Shelton. 535 U.S. 654, pp. 661-662. Opinion text
23. Supreme Court of the United States. (1984). Strickland v. Washington. 466 U.S. 668, pp. 687-696. Opinion text
24. Supreme Court of the United States. (1969). Frazier v. Cupp. 394 U.S. 731, pp. 737-739. Opinion text
25. Supreme Court of the United States. (2008). Rothgery v. Gillespie County. 554 U.S. 191, pp. 198-199, 211-213. Opinion text
26. Supreme Court of the United States. (2004). United States v. Patane. 542 U.S. 630, pp. 636-644; Kennedy concurrence pp. 644-645. Opinion text
27. Supreme Court of the United States. (2022). Vega v. Tekoh. No. 21-499, majority slip opinion pp. 1, 11-16. Opinion text
28. Kassin, S. M., Cleary, H. M. D., Gudjonsson, G. H., Leo, R. A., Meissner, C. A., Redlich, A. D., and Scherr, K. C. (2025). Police-induced confessions, 2.0: Risk factors and recommendations. Law and Human Behavior, 49(1), 7-53, PDF pp. 1, 14-18, 24-27; doi:10.1037/lhb0000593. Author-hosted journal article
29. Supreme Court of the United States. (1988). Arizona v. Roberson. 486 U.S. 675, pp. 682-688. Opinion text

One withheld page

John Brady's lawyer asked to see Donald Boblit's statements before Brady's Maryland murder trial. The prosecution showed him several but withheld Boblit's July 9, 1958 statement admitting the killing. Brady acknowledged participation in the crime and sought a verdict sparing him the death penalty. He learned of the withheld statement only after conviction and appeal.

Brady v. Maryland (1963) held that withholding favourable evidence material to guilt or punishment violates due process regardless of prosecutorial good faith. The relief in Brady itself was a new proceeding on punishment, not a new trial on guilt. That distinction matters: evidence can require disclosure because it affects the sentence even when it does not defeat the charge.

To understand when disclosure fits into a case, first distinguish the decisions preceding trial. An arrest, a judicial review of detention, a charging document and an arraignment do different jobs. Their order can vary. The sequence below uses federal procedure where specified and identifies constitutional rules that also constrain states.

The prosecutor selects charges within legal limits

Arrest does not itself settle whether a prosecution will continue. Prosecutors have broad discretion to bring supported charges or decline a case. That discretion does not erase constitutional limits. In a charging problem, separate whether the evidence supports the accusation from whether the government selected the defendant for an impermissible reason.

United States v. Armstrong (1996) required proof of discriminatory effect and discriminatory purpose for the selective-prosecution claim before it. Discovery, the process for obtaining information from the opposing party, also required a threshold showing. The Court demanded credible evidence that similarly situated people of another race could have been prosecuted but were not. A list showing only the race of defendants already prosecuted did not supply that comparison.

This is a demanding evidentiary threshold, not proof that discriminatory charging is lawful. Armstrong describes some evidence tending to show the claim's essential elements and reserves a question involving direct admissions of discriminatory purpose. Do not turn its comparator requirement into a claim that every kind of prosecution challenge follows an identical formula.

Blackledge v. Perry (1974) addresses a different problem. After a misdemeanour conviction, the defendant sought a new trial available under state law; the prosecutor then substituted a more serious charge. The Court prohibited that response because of the realistic danger of retaliation. Its reasoning does not create a presumption of vindictiveness whenever charges change before trial.

Key idea: Charging discretion is broad, but evidence, statutory elements and constitutional restrictions still matter. A count is an accusation, not an additional conviction.

Judicial review of detention has its own clock

When police arrest without a warrant, Gerstein v. Pugh (1975) requires a prompt judicial determination of probable cause before an extended restraint of liberty. This limited review need not be an adversarial hearing. A judicial officer can assess written information rather than hear witnesses cross-examined by counsel. A bare prosecutorial decision is not the independent judicial determination Gerstein requires.

County of Riverside v. McLaughlin (1991) supplies a burden-shifting rule. A determination within forty-eight hours will generally satisfy promptness, but it can still involve unreasonable delay. Delaying to gather additional evidence to justify the arrest, acting from ill will, or delaying for its own sake can violate the rule even within that period.

Beyond forty-eight hours, the government must show a genuine emergency or another extraordinary circumstance. An intervening weekend or a preference for combining hearings does not suffice. For example, from Friday at 9 pm to Monday at 10 am is sixty-one hours. Calling Monday the next business day does not account for the missing thirteen hours.

The federal initial-appearance requirement is a separate rule: Rule 5 ordinarily requires bringing an arrested person before a magistrate without unnecessary delay. A jurisdiction must satisfy each applicable obligation. The forty-eight-hour framework is not permission to delay every first appearance for two days.

First appearance and attachment of counsel

A federal felony initial appearance includes information about the complaint, counsel, release and other rights under Rule 5(d). It also provides an opportunity to consult counsel. It need not be the same event as the later arraignment on an indictment or information.

Under Rothgery v. Gillespie County (2008), the Sixth Amendment right attaches when adversary judicial criminal proceedings begin. That can occur through formal charge, preliminary hearing, indictment, information or arraignment. Rothgery's initial appearance qualified because the accused learned the accusation and his liberty was restricted. It was not necessary for a prosecutor to attend or know about the hearing.

Attachment can therefore precede a first appearance, for example when an indictment already exists. And attachment is distinct from deciding whether a particular proceeding is a critical stage requiring counsel's presence absent waiver. Gerstein's limited, nonadversarial probable-cause review is not itself such a critical stage. Combining several functions in one hearing requires examining each function rather than relying on its label.

Release conditions and preventive detention

The Eighth Amendment prohibits excessive bail. Stack v. Boyle (1951) required bail tied to securing the defendant's appearance, based on the individual case. It rejected treating the accusation alone as an adequate explanation for unusually high amounts. Stack does not mean every accused person has an unconditional right to release.

United States v. Salerno (1987) upheld the federal Bail Reform Act's carefully limited preventive-detention provisions against a facial challenge. The Court treated the scheme as regulation for safety, not punishment for an unproved crime. Its reasoning relied on restricted eligibility, a hearing, counsel, findings and other safeguards. A prediction of danger by itself does not reproduce those protections.

Read the current federal statute, 18 U.S.C. section 3142, in steps. Start with release on recognisance or an unsecured bond unless that will not reasonably assure appearance or safety. If conditions are needed, the statute calls for the least restrictive combination that will reasonably assure those aims. A financial condition may not be used to cause pretrial detention. Detention requires the statutory route and findings; the safety finding requires clear and convincing evidence.

For a hypothetical, an accused person cannot afford a proposed bond but can comply with reporting and travel restrictions. The federal court must evaluate permitted conditions and the statutory detention grounds. Inability to pay does not establish guilt or supply the necessary safety finding. State release systems have their own statutes and constitutional constraints; this federal example does not describe every state's current practice.

Indictment, information and preliminary hearing

An indictment comes from a grand jury. An information is filed by a prosecutor. Federal Rule 7 generally requires an indictment for a capital offence or one punishable by more than a year in prison; a defendant can waive indictment for a noncapital felony under the rule's conditions. Lesser offences can follow other permitted charging routes.

Hurtado v. California (1884) held that the Fourteenth Amendment does not require states to use the federal grand-jury model. States may authorise prosecution by information. Whether a preliminary hearing is available or required depends on the governing rules and any valid waiver. An information does not inherently guarantee a preliminary hearing.

Rule 5.1 ordinarily requires a preliminary hearing within fourteen days of initial appearance if the defendant is detained and twenty-one if not, subject to exceptions and permitted extensions. If probable cause is absent, the complaint is dismissed and the defendant discharged on that complaint; the rule does not bar a later prosecution. This hearing is not the same as the earlier Gerstein custody review.

Federal grand-jury secrecy is also specific. Rule 6 restricts disclosure by listed participants and provides exceptions. It does not impose its secrecy duty on witnesses merely because they testify. Statements such as everything about a grand jury is secret are therefore too broad.

Which duty governs favourable evidence at the grand jury?

United States v. Williams (1992) rejected using federal courts' supervisory power to dismiss an otherwise valid indictment because the prosecutor failed to present substantial exculpatory evidence. That is the judicial rule addressed by the case. It does not mean prosecutors operate without any other instruction to disclose favourable information.

The Department of Justice's current policy, section 9-11.233, requires a federal prosecutor who personally knows substantial evidence directly negating the subject's guilt to present or disclose it to the grand jury before seeking indictment. The manual distinguishes that policy from a defendant's judicial entitlement to dismissal. State duties require separate examination.

The upshot: Keep three questions apart: what the Constitution requires, what a court rule or statute requires, and what a prosecutor's office requires by policy. The answers can differ even for the same piece of evidence.

Arraignment and the two speedy-trial inquiries

Federal Rule 10 provides for giving the defendant the indictment or information, reading or explaining the charge, and requesting a plea. A not-guilty plea contests the prosecution's case. A guilty plea requires the separate safeguards of Rule 11; a no-contest plea requires the court's consent. Arraignment is not itself a finding that the accusation is true.

Barker v. Wingo (1972) assesses a constitutional speedy-trial claim by weighing the delay's length, its reasons, the defendant's assertion of the right, and prejudice. No single factor automatically decides every case. Prejudice can include oppressive confinement, anxiety and harm to the defence. The remedy for a constitutional violation is dismissal.

The federal Speedy Trial Act supplies separate deadlines. Under 18 U.S.C. section 3161, the ordinary charging period is thirty days from the relevant federal arrest or summons. For a not-guilty case, the ordinary trial period is seventy days from the later of public filing of the indictment or information and appearance before a judicial officer of the court where the charge is pending. Statutory exclusions and exceptions matter.

Suppose the indictment is publicly filed on June 1 and that appearance occurs June 10. Use the later event for this ordinary seventy-day calculation, then account for legally excluded periods. Counting seventy uninterrupted calendar days from the arrest could answer the wrong question. Compliance with the statute and the constitutional balancing inquiry remain separate issues.

Disclosure begins with several overlapping duties

Federal Rule 16 gives access to specified categories, subject to its request and other conditions, including defendant statements, records, documents, test results and expert information. Its current expert provision requires a complete statement of the opinions to be offered, bases and reasons, and specified qualifications and history. Calling it merely a summary of expert testimony understates the rule. Some defence disclosure duties arise when the rule's reciprocal conditions are met.

The Jencks Act, 18 U.S.C. section 3500, generally requires production on defence motion of qualifying prior statements related to a government witness's direct testimony after that testimony. That timing rule does not eliminate separate constitutional disclosure duties. Rule 5(f) also requires a court order confirming Brady obligations at the first scheduled date with prosecutor and defence counsel present.

These provisions do not require delivery of the entire investigative file in every case. Nor should a prosecutor treat the minimum needed to avoid reversal as the complete measure of disclosure. Court orders, statutes and applicable policies can require more. DOJ's section 9-5.001 expressly adopts disclosure duties broader than the constitutional minimum, while disclaiming the creation of independently enforceable rights.

Apply Brady in three steps

First ask whether the evidence favours the accused. It may support innocence, reduce punishment or undermine a prosecution witness's credibility. Giglio v. United States (1972) involved an undisclosed promise not to prosecute a key witness. One prosecutor's promise was attributable to the office; an uninformed trial prosecutor did not erase the problem.

Second ask whether the prosecution suppressed it. The prosecutor must learn of favourable evidence known to others acting for the government in the case, including police, under Kyles v. Whitley (1995). This is a duty concerning the prosecution team, not automatic attribution of every record held anywhere in government. A specific defence request is not required for the constitutional duty.

Third assess materiality. United States v. Bagley (1985) asks whether there is a reasonable probability of a different outcome with disclosure. Kyles explains that the defendant need not prove a different verdict was more likely than not. The question is whether withholding the evidence undermines confidence in the result, considering the favourable evidence together in the context of the case.

Imagine that the main identification witness first described someone of a different height and later received an undisclosed promise of leniency. The first item challenges the identification; the second challenges the witness's incentive. Evaluate their combined effect. The conclusion still depends on the remaining evidence, so neither the number of documents nor the word favourable decides materiality alone.

The limit concerning guilty pleas

United States v. Ruiz (2002) held that the Constitution does not require disclosure of impeachment information before a guilty plea. The proposed agreement there preserved disclosure of information establishing factual innocence. Do not extend the impeachment holding into a blanket permission to conceal every kind of favourable evidence before every plea.

A real disclosure question therefore requires identifying the kind of evidence, the procedural stage, the jurisdiction and any applicable rule, order or policy. Ruiz limits one constitutional claim; it does not cancel all of these other duties.

Common misconceptions

• A judge can always wait forty-eight hours. McLaughlin permits a challenge to an unreasonable delay within that period.
• The right to counsel always begins at first appearance. A qualifying formal step such as indictment may already have triggered attachment.
• A dangerousness label alone permits detention. Salerno relied on a limited statutory scheme and procedural safeguards.
• Ordinary evidence rules apply at a federal preliminary hearing. Rule 1101 makes an exception while preserving privilege rules.
• Brady requires proving acquittal was more likely than not. Kyles rejects that burden and requires cumulative assessment of materiality.
• Williams or Ruiz removes every disclosure duty. Each addresses a specific judicial question; additional governing duties must still be checked.

The short version

For each event on a case timeline, name its purpose before applying a deadline or burden. Probable-cause review justifies continued restraint; charging identifies the alleged offence; attachment starts the Sixth Amendment protection; release proceedings apply their own standards; arraignment calls for a plea. Disclosure duties must be assessed throughout, with constitutional materiality distinguished from broader rules and policies.

Remember: This is a study of federal procedure and identified constitutional holdings, reviewed on September 28, 2026. It does not establish the rules for every state or resolve an individual case. The current rules compilation and pending-amendment status were checked separately.

Sources

1. Supreme Court of the United States. (1963). Brady v. Maryland. 373 U.S. 83, pp. 84-88. Source text
2. Supreme Court of the United States. (1996). United States v. Armstrong. 517 U.S. 456, pp. 464-470. Source text
3. Supreme Court of the United States. (1974). Blackledge v. Perry. 417 U.S. 21, pp. 27-29. Source text
4. Supreme Court of the United States. (1975). Gerstein v. Pugh. 420 U.S. 103, pp. 114, 119-123. Source text
5. Supreme Court of the United States. (1991). County of Riverside v. McLaughlin. 500 U.S. 44, pp. 56-57. Source text
6. Supreme Court of the United States. (1951). Stack v. Boyle. 342 U.S. 1, pp. 4-6. Source text
7. Supreme Court of the United States. (1987). United States v. Salerno. 481 U.S. 739, pp. 747-755. Source text
8. Supreme Court of the United States. (1884). Hurtado v. California. 110 U.S. 516, pp. 538. Source text
9. Supreme Court of the United States. (1992). United States v. Williams. 504 U.S. 36, pp. 45-55. Source text
10. Supreme Court of the United States. (1972). Barker v. Wingo. 407 U.S. 514, pp. 522, 530-533. Source text
11. Supreme Court of the United States. (1972). Giglio v. United States. 405 U.S. 150, pp. 153-155. Source text
12. Supreme Court of the United States. (1985). United States v. Bagley. 473 U.S. 667, pp. 676, 682-685. Source text
13. Supreme Court of the United States. (1995). Kyles v. Whitley. 514 U.S. 419, pp. 434-438. Source text
14. Supreme Court of the United States. (2002). United States v. Ruiz. 536 U.S. 622, pp. 629-633. Source text
15. Supreme Court of the United States. (2008). Rothgery v. Gillespie County. 554 U.S. 191, pp. 198-199, 211-213. Source text
16. Administrative Office of the United States Courts. (2025). Federal Rules of Criminal Procedure. December 1, 2025 compilation, Rules 5(a),(d),(f), 5.1, 6, 7, 10, 11(a), 16(a)(1),(b). Source text
17. Federal Rules of Evidence. (2026). Federal Rule of Evidence 1101. Current rule text inspected September 28, 2026, Rule 1101(c),(d)(2)-(3). Source text
18. United States Congress. (2026). 18 U.S.C. section 3142. Current statutory text inspected September 28, 2026, subsections (b),(c)(1)-(2),(e)-(g). Source text
19. United States Congress. (2026). 18 U.S.C. section 3161. Current statutory text inspected September 28, 2026, subsections (b),(c)(1),(h). Source text
20. United States Congress. (2026). 18 U.S.C. section 3500. Current statutory text inspected September 28, 2026, subsections (a)-(b). Source text
21. United States Department of Justice. (2026). Justice Manual: Grand Jury. Current policy inspected September 28, 2026, section 9-11.233. Source text
22. United States Department of Justice. (2026). Justice Manual: Issues Related to Discovery, Trials, and Other Proceedings. Current policy inspected September 28, 2026, sections 9-5.001(B),(D),(F), 9-5.002 Step 3. Source text

A forged cheque for eighty-eight dollars and thirty cents

Paul Lewis Hayes was indicted in Kentucky for uttering a forged instrument. The instrument was a cheque for $88.30. The offence carried two to ten years.

The prosecutor made an offer: plead guilty and I will recommend five years. He also said, on the record, what would happen if Hayes refused. He would return to the grand jury and seek a second indictment under the Kentucky Habitual Criminal Act. Hayes had two prior felony convictions, and under that Act a third conviction carried a mandatory sentence of life imprisonment.

Hayes refused. The prosecutor did exactly what he had said he would do. A jury convicted Hayes on the forged cheque, the habitual criminal count was proved, and he was sentenced to life.

Stop here and work the problem before reading the answer. Two descriptions of that exchange are available. On one, a prosecutor with probable cause for a greater charge offered a discount for saving the state a trial, and a defendant who fully understood the terms chose the risk. On the other, a man received a life sentence for exercising a constitutional right, and the eighty-eight dollar cheque is the tell: nothing about his conduct changed between the offer and the sentence except that he said no.

Bordenkircher v. Hayes, 434 U.S. 357 (1978), adopted the first description, five to four. In the give and take of plea negotiation there is no element of punishment or retaliation, Justice Stewart wrote, so long as the accused is free to accept or reject the offer, and the prosecutor had probable cause to bring the greater charge all along. The dissent answered that the state was penalising the assertion of a right, and that calling it a negotiation did not change what it was.

Whatever you conclude, notice what the case establishes: the threat to charge more, made explicitly to induce a plea, is constitutional. That is the legal foundation of the machine this lesson describes. And a standing note, more pointed here than anywhere else in the course: this is general legal education, not legal advice, and no one facing a plea decision should make it on the strength of a lesson rather than a lawyer.

How much of the system this is

In Missouri v. Frye (2012), the Supreme Court set out the figures it was working from: ninety-seven per cent of federal convictions and ninety-four per cent of state convictions are the result of guilty pleas. In the companion case, Lafler v. Cooper, Justice Kennedy drew the conclusion in a sentence that has been quoted ever since, describing criminal justice today as for the most part a system of pleas, not a system of trials.

Sit with what that means for the rest of this course. The confrontation right, the reasonable doubt standard, the jury, the rules of evidence, the cross-examination of the state's witnesses: those govern the small remainder. For the overwhelming majority of defendants, the operative procedure is a conversation between two lawyers, and the operative safeguard is a fifteen minute colloquy in open court.

So what?: If you want to know what American criminal procedure actually does to people, study the plea, not the trial.

Where it came from, and when the Court blessed it

Plea bargaining is not ancient. Early nineteenth century American court records show trials as the ordinary disposition, and judges of that era were often openly hostile to guilty pleas induced by promises. It grew after the Civil War alongside professional police forces, professional prosecutors, rising urban caseloads, and increasingly complex trials. By 1931 the Wickersham Commission was documenting it as routine and largely invisible.

The Supreme Court did not squarely approve it until 1970. Brady v. United States held that a guilty plea is not involuntary merely because it was motivated by the desire to avoid a heavier sentence, including the death penalty. A year later, in Santobello v. New York (1971), Chief Justice Burger went further and called plea bargaining an essential component of the administration of justice, to be encouraged if properly administered. Santobello also supplied a real protection: when a prosecutor makes a promise that induces a plea, the promise must be kept, and a broken one entitles the defendant to relief.

The same term produced North Carolina v. Alford (1970). Henry Alford pleaded guilty to second-degree murder while telling the court he had not done it, in order to avoid a capital trial. The Court held the plea valid: a defendant may plead guilty while protesting innocence where the plea is voluntary and the record contains a strong factual basis. The Alford plea is the sharpest illustration of what the system is actually asking people to do.

What makes a plea valid

A guilty plea waives three constitutional rights at once, and Boykin v. Alabama (1969) requires the record to show affirmatively that the waiver was knowing and voluntary. The three are the privilege against compelled self-incrimination, the right to trial by jury, and the right to confront one's accusers.

In federal court that showing is made through the Rule 11 colloquy, in which the judge, addressing the defendant personally in open court, establishes that he understands the charge, the maximum penalty and any mandatory minimum, and the rights he is giving up, that the plea is not the product of force or of promises outside the agreement, and that there is a factual basis for it.

Two limits on that ritual are worth naming honestly. First, the colloquy asks whether anyone threatened the defendant, and the threat that actually produced most pleas, the prospect of a much longer sentence after trial, is not what the question means. Second, under United States v. Ruiz (2002), the government need not disclose impeachment evidence before the plea, so the defendant answers the judge's questions without knowing how weak the state's witnesses may be.

When counsel gets the negotiation wrong

If the plea is where cases are decided, then effective assistance at the plea stage matters more than effective assistance at trial. The Court took twenty-seven years after Strickland to say so clearly, and then did it in three cases.

• Hill v. Lockhart (1985) applied Strickland to pleas: the prejudice question is whether, but for counsel's errors, the defendant would have gone to trial.
• Padilla v. Kentucky (2010). Jose Padilla had been a lawful permanent resident for over forty years and had served in the United States armed forces in Vietnam. His lawyer told him he did not have to worry about immigration status. In fact the drug offence made deportation virtually mandatory. The Court held that counsel must advise a noncitizen client whether a plea carries a risk of deportation, rejecting the old distinction between direct and collateral consequences for this purpose.
• Missouri v. Frye (2012). The prosecutor sent two written offers, one of them a misdemeanour with ninety days. Frye's lawyer never told him they existed, and they expired. The Court held that counsel has a duty to communicate formal offers.
• Lafler v. Cooper (2012). Counsel advised rejecting an offer because he wrongly believed the state could not prove intent to murder where the victim had been shot below the waist. Cooper went to trial, was convicted, and received a sentence several times longer than the offer. The Court held that a defendant may show prejudice from advice that caused him to reject a plea, and approved a remedy of ordering the offer reoffered.

What matters here: A defendant now has a constitutional right to competent advice about an offer, but the right runs to the advice, not to the offer. The prosecutor is under no obligation to make one.

The trial penalty, and where the leverage comes from

The gap between the sentence offered for a plea and the sentence imposed after a conviction at trial is usually called the trial penalty. In 2018 the National Association of Criminal Defense Lawyers published a book-length study of it under that name, arguing that the differential has grown large enough that the right to trial is exercised only by defendants who can afford to gamble years of their life on it.

Where does that differential come from? Three sources, all of them lawful:

1. Charge stacking. One incident can support several counts, and each count adds exposure. Dropping counts costs the prosecutor nothing she was ever going to prove separately.
2. Mandatory minimums. A statute that fixes a floor moves the decision from the judge to the prosecutor, because the choice of charge now determines the sentence. In federal drug cases, filing an information about prior convictions under 21 U.S.C. section 851 raises the mandatory minimum, and the decision whether to file it belongs entirely to the prosecutor.
3. Acceptance of responsibility. Sentencing schemes reduce the sentence for pleading guilty. Read from the other end, they increase it for going to trial.

Defenders of the system reply that the discount is what a defendant is paying for, that the post-trial sentence is the real one, and that a system in which pleading guilty produced no benefit would produce no pleas and therefore no functioning courts. That reply is serious. Notice, though, that it concedes the structural point: the system depends on making trial expensive.

The innocence problem

An innocent defendant should refuse any plea, on the theory that he cannot be convicted. The theory assumes he is confident about the outcome, indifferent to risk, and free while he waits. Often none of that is true.

Consider a person held on a bond he cannot post, charged with a misdemeanour, offered a plea to time served. Pleading guilty means walking out today. Refusing means weeks in jail awaiting trial, which for many people means losing a job, a tenancy, or custody of a child. The rational choice for an innocent person in that position is frequently to plead guilty, and this is a well documented feature of lower criminal courts rather than a hypothetical. Malcolm Feeley's 1979 study of a Connecticut misdemeanour court made the point in its title: the process is the punishment.

The National Registry of Exonerations records exonerations of people who had pleaded guilty, concentrated in drug cases and in high volume misdemeanour courts. Every one of them went through a Rule 11 style colloquy and told a judge, under oath, that they were guilty and that nobody had pressured them.

The best case for the system, and the best reply

The strongest defence is contractual, argued most fully by Robert Scott and William Stuntz in 1992. A plea is an exchange from which both parties gain: the state saves the cost and risk of trial, the defendant buys certainty and a lower sentence. Forbidding the exchange would not give defendants trials they want; it would give them trials they would rather have traded away, and would leave them worse off by their own lights. On this view, restricting plea bargaining is paternalism dressed as protection.

The strongest reply, argued by Stephanos Bibas in 2004, accepts the contract frame and attacks its assumptions. A well functioning bargain requires parties who know the odds and can act on them. Real plea negotiation is distorted by information asymmetry, since the defence often has not seen the state's evidence and is not entitled to impeachment material; by agency costs, since defence counsel carrying two hundred cases has different incentives from the client; by resources, since retained counsel with time to investigate produces different offers; by pretrial detention, which imposes a cost on refusing that has nothing to do with the merits; and by ordinary risk aversion in the face of decades. Prices set under those conditions do not track the probability of conviction, so the bargain does not do the work the defence claims for it.

The core of it: The dispute is not about whether trades should be allowed. It is about whether the conditions under which these particular trades are made can be called consent.

Common misconceptions

• Plea bargaining is a modern shortcut that could simply be banned. It has been the ordinary disposition for over a century, and the Court has treated it as essential since 1971.
• Threatening a harsher charge to induce a plea is coercion. Bordenkircher holds it constitutional where probable cause exists for the greater charge.
• You cannot plead guilty if you say you are innocent. An Alford plea allows exactly that, given voluntariness and a strong factual basis.
• The judge's colloquy screens out coerced pleas. It screens for threats outside the bargain; the pressure that produces most pleas is the bargain itself.
• A defendant has a right to a plea offer. He has a right to competent advice about an offer that is made, not to receive one.
• Innocent people would never plead guilty. Detention, caseloads, risk, and time-served offers make it a rational choice, and documented exonerations follow guilty pleas.

Pulling it together

• Bordenkircher permits a prosecutor to threaten and then bring a much greater charge when a defendant refuses to plead.
• The Court's own figures put guilty pleas at ninety-seven per cent of federal and ninety-four per cent of state convictions.
• Brady v. United States and Santobello approved bargaining; Santobello also requires the prosecution to keep its promises.
• Boykin and Rule 11 require a record showing a knowing and voluntary waiver of three specific rights.
• Hill, Padilla, Frye, and Lafler apply the Sixth Amendment to the negotiation itself.
• The trial penalty is built from charge stacking, mandatory minimums, and sentencing credit for acceptance of responsibility.
• The contract defence of plea bargaining is strong on its own terms; the reply attacks the conditions under which the bargains are struck.

Sources

1. Legal Information Institute. (n.d.). Plea bargain. Cornell Law School. law.cornell.edu
2. Wikipedia. (n.d.). Bordenkircher v. Hayes. en.wikipedia.org
3. Wikipedia. (n.d.). North Carolina v. Alford. en.wikipedia.org
4. Bureau of Justice Statistics. (n.d.). Bureau of Justice Statistics. United States Department of Justice. bjs.ojp.gov
5. Scott, R. E., and Stuntz, W. J. (1992). Plea bargaining as contract. Yale Law Journal, 101(8).
6. Feeley, M. M. (1979). The Process Is the Punishment: Handling Cases in a Lower Criminal Court. Russell Sage Foundation.

Ten votes out of twelve

In 2016 a Louisiana jury found Evangelisto Ramos guilty of a serious crime by a vote of ten to two, and he was sentenced to life in prison without the possibility of parole. In forty-eight states and in federal court those two dissenting votes would have produced a hung jury. In Louisiana they produced a conviction.

Louisiana had permitted non-unanimous felony verdicts since its constitutional convention of 1898, a convention whose own stated purpose included establishing the supremacy of the white race in the state. Oregon adopted its rule in the 1930s in a period of open nativist agitation. When the question reached the Supreme Court in 1972 the Justices had split so oddly that the rule survived on a single concurrence, and it stood for another forty-eight years.

Ramos v. Louisiana, 590 U.S. 83 (2020), ended it. The Sixth Amendment right to a jury trial, as incorporated against the states, requires a unanimous verdict to convict of a serious offence. A year later Edwards v. Vannoy (2021) held that the ruling does not apply retroactively on federal collateral review, so people convicted by divided juries before 2020 whose appeals were finished did not get new trials.

That sequence sets up the whole lesson. Trial rights are specific, they are the product of contested history rather than of abstraction, and what happens after conviction is governed by a separate body of law that most courses treat as an afterthought. This is general legal education rather than legal advice, and it is describing the federal constitutional floor; every state adds to it.

The jury: when you get one, and who is on it

Duncan v. Louisiana (1968) incorporated the jury trial right against the states. It does not cover everything. Under Baldwin v. New York (1970) the right attaches to serious offences, meaning those carrying a potential sentence of more than six months, which leaves a very large volume of misdemeanour prosecutions to be tried by a judge alone.

Size and unanimity took fifty years to settle. Williams v. Florida (1970) approved six-member juries; Ballew v. Georgia (1978) held that five is too few; Ramos requires unanimity whatever the size.

Composition is governed by two separate doctrines that students routinely merge.

• The fair cross-section requirement applies to the venire, the pool from which jurors are drawn. Taylor v. Louisiana (1975) struck down a scheme that effectively excluded women. No defendant is entitled to a jury of any particular composition; he is entitled to a pool from which distinctive groups have not been systematically excluded.
• Batson applies to the strikes used on the panel. In Batson v. Kentucky (1986) the Court held that a prosecutor may not use peremptory challenges to remove jurors on account of race, and set out three steps: the objecting party makes a prima facie showing of discrimination; the striking party offers a race-neutral explanation; the judge decides whether purposeful discrimination has been proved. J.E.B. v. Alabama (1994) extended it to sex.

Batson's weakness is step two, because almost any explanation qualifies as facially neutral, and step three asks a trial judge to find that a lawyer in front of him lied. Flowers v. Mississippi (2019) shows what it takes to win: the same prosecutor tried Curtis Flowers six times for the same crime, and across those trials the pattern of strikes against Black jurors was extreme enough that the Court reversed.

Remember: The cross-section right governs the pool and asks about systematic exclusion; Batson governs the strikes and asks about purposeful discrimination in this case.

Confrontation, and the end of the reliability test

Michael Crawford stabbed a man who he said had tried to assault his wife. His wife Sylvia gave a tape-recorded statement to police that undercut his self-defence claim. She did not testify, because a marital privilege kept her off the stand, so the prosecution played the tape.

Under the test then in force, from Ohio v. Roberts (1980), out-of-court statements were admissible if the declarant was unavailable and the statement bore adequate indicia of reliability. The Washington courts found the tape reliable.

Crawford v. Washington, 541 U.S. 36 (2004), discarded that framework. Justice Scalia held that the Confrontation Clause is not a rule about reliability at all. It commands a procedure: testimonial hearsay is inadmissible unless the declarant is unavailable and the defendant had a prior opportunity to cross-examine. Reliability is what cross-examination is for, and a judge's finding of reliability is not a substitute for it.

The obvious follow-up question was what makes a statement testimonial, and the answer arrived in stages.

• Davis v. Washington (2006) set the primary purpose test. A 911 call made to summon help during an ongoing emergency is not testimonial; statements given to officers after the emergency has passed, to establish what happened, are.
• Melendez-Diaz v. Massachusetts (2009) held that a forensic laboratory certificate is testimonial, so the analyst must be available for cross-examination. Bullcoming v. New Mexico (2011) added that a surrogate analyst who did not perform the test will not do.
• Smith v. Arizona (2024) closed a workaround. When an expert testifies to an absent analyst's statements in support of his own opinion, and those statements support the opinion only if they are true, they are being offered for their truth and the Confrontation Clause applies.
• Giles v. California (2008) preserved forfeiture by wrongdoing: a defendant who makes a witness unavailable, intending that result, loses the objection.

Proof beyond a reasonable doubt, and who carries what

In re Winship (1970) held that due process requires proof beyond a reasonable doubt of every fact necessary to constitute the crime charged. Two consequences follow that are worth stating precisely.

First, the judge may not lighten that load with a presumption. Sandstrom v. Montana (1979) struck down an instruction that the law presumes a person intends the ordinary consequences of his voluntary acts, because a jury could read it as shifting the burden on intent. Permissive inferences the jury may draw are fine; mandatory presumptions are not.

Second, the rule attaches to elements, not to defences. Under Patterson v. New York (1977) a state may place the burden of proving an affirmative defence on the defendant, so long as it has not simply relabelled an element as a defence. That is why, as Module 4 showed, the allocation of the burden on self-defence or insanity varies so much across states.

One more trial rule belongs here. Under Griffin v. California (1965), neither the prosecutor nor the judge may invite the jury to draw an adverse inference from a defendant's decision not to testify.

What sentencing is for, and why the answers conflict

Conviction ends one inquiry and starts another with a different logic. Five purposes are conventionally offered, and it is worth seeing that they point in different directions on the same case.

Restorative approaches add a sixth question about repairing the harm to the victim and the community. Federal judges are directed by statute, at 18 U.S.C. section 3553(a), to consider several of these at once, which is a real instruction rather than a rhetorical one: a judge weighing deterrence and rehabilitation on the same facts is being asked to reconcile aims that do not reconcile.

From discretion to guidelines, and partway back

Until the 1970s most American sentencing was indeterminate. A judge picked a wide range, and a parole board decided the actual release date based on progress in prison. Judge Marvin Frankel's 1973 book Criminal Sentences: Law Without Order attacked the system for lawlessness, arguing that the same defendant could receive wildly different sentences depending on which judge he drew, and that this was not discretion but arbitrariness.

The reform coalition that followed was unusual, joining critics who wanted less disparity with critics who wanted more severity. The Sentencing Reform Act of 1984 created the United States Sentencing Commission, abolished federal parole, and produced guidelines effective in 1987 that computed a narrow range from the offence level and the defendant's criminal history. Mistretta v. United States (1989) rejected a challenge to the Commission's constitutionality.

Then the jury right caught up with the guidelines.

The Apprendi line

Charles Apprendi fired shots into the home of a Black family in New Jersey and pleaded guilty to a firearms count carrying five to ten years. At sentencing the judge found, by a preponderance of the evidence, that the shooting had been racially motivated, and applied a hate crime enhancement to impose twelve years.

Apprendi v. New Jersey, 530 U.S. 466 (2000), reversed. Other than the fact of a prior conviction, any fact that increases the penalty for a crime beyond the prescribed statutory maximum must be submitted to a jury and proved beyond a reasonable doubt. The principle then worked through the system case by case.

Gall v. United States (2007) confirmed that appellate courts review sentences outside the advisory range for abuse of discretion rather than requiring extraordinary justification. The practical result is a hybrid: judges must calculate the guideline range and consider the statutory purposes, and may then depart, subject to deferential review.

In short: A fact that raises the ceiling or the floor of a sentence is an element in everything but name, and the jury must find it beyond a reasonable doubt.

What the Eighth Amendment forbids

The cruel and unusual punishments clause is interpreted, since Trop v. Dulles (1958), by reference to evolving standards of decency that mark the progress of a maturing society, measured largely by counting state legislative choices and jury practice.

It has done the most work in two places.

Capital punishment. Furman v. Georgia (1972) invalidated the death penalty as then administered, on the ground that it was imposed arbitrarily. Gregg v. Georgia (1976) upheld revised statutes that guided discretion through bifurcated proceedings and aggravating and mitigating factors. Since then the Court has drawn categorical lines: Coker v. Georgia (1977), no death penalty for the rape of an adult woman; Kennedy v. Louisiana (2008), none for the rape of a child where no death occurred; Atkins v. Virginia (2002), none for defendants with intellectual disability; Roper v. Simmons (2005), none for offenders under eighteen at the time of the crime.

Juvenile sentences. Graham v. Florida (2010) barred life without parole for juveniles in non-homicide cases. Miller v. Alabama (2012) barred mandatory life without parole for juveniles in any case, requiring individualised consideration of youth. Montgomery v. Louisiana (2016) made Miller retroactive, and Jones v. Mississippi (2021) held that a sentencer need not make a separate factual finding of permanent incorrigibility.

Outside those categories, proportionality review of prison terms is very weak. Solem v. Helm (1983) once struck down a life sentence for a series of minor property offences, but Harmelin v. Michigan (1991) upheld a mandatory life sentence for possessing a large quantity of cocaine, and Ewing v. California and Lockyer v. Andrade (both 2003) upheld sentences of twenty-five years to life under California's three strikes law for shoplifting offences that were the third strike. The operative standard is gross disproportionality, and it almost never bites.

The part of the sentence nobody reads out

The judgment states a term of custody and supervision. It does not state that the conviction may also bar the person from public housing, from many occupational licences, from serving on a jury, from possessing a firearm, and, in many states, from voting for some period; that it may trigger registration requirements; or that for a noncitizen it may make removal from the country effectively automatic, which is why Padilla in the last lesson mattered so much. These collateral consequences are imposed by statutes scattered across a code, and they often outlast the sentence itself.

The point: The sentence pronounced in court is a subset of the punishment imposed by law.

Common misconceptions

• Every criminal defendant gets a jury. The right attaches to offences carrying more than six months, leaving most misdemeanours to bench trials.
• A defendant is entitled to a jury reflecting the community's composition. The fair cross-section right governs the pool, not the panel that is finally seated.
• Batson ended discriminatory strikes. It requires proof of purposeful discrimination, and almost any facially neutral reason satisfies step two.
• Confrontation is about whether the statement is reliable. Crawford rejected exactly that approach in favour of a procedural rule about testimonial statements.
• The federal sentencing guidelines are binding. Booker made them advisory; judges must calculate and consider them, then may depart.
• The Eighth Amendment requires sentences to be proportionate. For terms of years the standard is gross disproportionality, and challenges nearly always fail.

Looking back

• Duncan incorporated the jury right for serious offences; Ramos requires unanimity, and Edwards v. Vannoy denied it retroactive effect on collateral review.
• Taylor governs the venire through the fair cross-section requirement; Batson governs peremptory strikes through its three-step procedure.
• Crawford replaced reliability with a procedural rule for testimonial hearsay, refined by the primary purpose test and the forensic analyst cases.
• Winship requires proof beyond a reasonable doubt of every element; Sandstrom forbids mandatory presumptions and Patterson permits burdens on affirmative defences.
• The five purposes of sentencing point in different directions, and statutes ask judges to weigh them together.
• The Apprendi line moved facts that raise a sentencing ceiling or floor to the jury and made the federal guidelines advisory.
• The Eighth Amendment draws categorical lines around capital and juvenile sentences and almost none around terms of years.

Sources

1. Legal Information Institute. (n.d.). Sixth Amendment. Cornell Law School. law.cornell.edu
2. Legal Information Institute. (n.d.). Eighth Amendment. Cornell Law School. law.cornell.edu
3. Wikipedia. (n.d.). Crawford v. Washington. en.wikipedia.org
4. Wikipedia. (n.d.). Apprendi v. New Jersey. en.wikipedia.org
5. Congressional Research Service. (n.d.). Constitution Annotated: Sixth Amendment. constitution.congress.gov
6. Frankel, M. E. (1973). Criminal Sentences: Law Without Order. Hill and Wang.