Criminal Defenses

Before analyzing specific defenses, students must distinguish between failure of proof and an affirmative defense.

If the prosecution cannot prove an element beyond a reasonable doubt, the defendant is not guilty of that offense. For example, if theft requires intent to permanently deprive and the defendant honestly believed the property was his own, the prosecution may fail to prove the required mens rea.

A defense, by contrast, may arise even when the prosecution can prove the offense elements. If a defendant intentionally strikes another person, the elements of battery may be satisfied. But if the defendant used reasonable force to repel an imminent unlawful attack, self-defense may justify the act.

Some defenses require the defendant only to produce evidence. Others require the defendant to prove the defense by a specified standard. Some require the prosecution to disprove the defense beyond a reasonable doubt once properly raised. The allocation of burdens varies by jurisdiction and by defense. But the prosecution always bears the constitutional burden of proving every element of the offense beyond a reasonable doubt.

Defenses are often divided into justifications and excuses.

A justification defense says the defendant’s conduct was not wrongful under the circumstances. The classic example is self-defense. A person who uses reasonable force to stop an imminent unlawful attack has committed a physical act that would otherwise be criminal, but the law treats the act as justified.

An excuse defense says the conduct was wrongful, but the defendant should not be held criminally blameworthy. Insanity, duress, and certain intoxication doctrines may operate as excuses. The law does not necessarily approve the act, but it recognizes that punishment may be inappropriate or reduced because of the defendant’s condition or circumstances.

The distinction matters because it affects policy and sometimes doctrine. Justified conduct is treated as right or permissible. Excused conduct is treated as wrong but not blameworthy enough for conviction or full punishment.

Self-defense is the most important justification defense. It allows a person to use force to protect against unlawful force by another.

The basic rule is that a defendant may use reasonable force when the defendant honestly and reasonably believes such force is necessary to prevent imminent unlawful harm.

Several elements matter.

First, the threat must be unlawful. A person may not use self-defense against lawful arrest or justified force, except under limited modern rules or when excessive force is used.

Second, the threat must be imminent. Self-defense responds to immediate danger, not future revenge or past harm. A person threatened with possible harm next week generally cannot attack today and claim self-defense.

Third, the defendant must believe force is necessary. If safe alternatives clearly exist, the necessity of force may be questioned.

Fourth, the amount of force must be proportionate. Nondeadly force may be met with reasonable nondeadly force. Deadly force is justified only against threats of death, serious bodily injury, or certain serious felonies, depending on the jurisdiction.

Deadly force is force likely to cause death or serious bodily injury. Shooting, stabbing, or striking with a deadly weapon usually qualifies.

A person may use deadly force only if the person reasonably believes deadly force is necessary to prevent death, serious bodily injury, or another qualifying grave harm. A shove does not justify gunfire. A minor slap does not justify a knife attack.

Jurisdictions differ on retreat. Some impose a duty to retreat before using deadly force if the defendant can retreat safely. Others follow “stand your ground” principles and do not require retreat from a place where the defendant lawfully may be.

The castle doctrine traditionally provides that a person has no duty to retreat in the home before using deadly force against an unlawful intruder, although modern statutes vary.

An initial aggressor generally may not claim self-defense unless the aggressor withdraws and communicates withdrawal, or the other person escalates the encounter beyond the original aggression.

Suppose Alex starts a fistfight. Alex cannot immediately claim self-defense when the victim punches back. But if Alex clearly withdraws and says, “I’m done, I’m leaving,” and the other person continues attacking, Alex may regain the right of self-defense.

Escalation also matters. If Alex begins with nondeadly force and the other person suddenly responds with deadly force, some jurisdictions allow Alex to use necessary force to prevent death or serious harm, even though Alex started the conflict. The rules vary, so students should follow the jurisdiction supplied.

Defense of others allows a person to use force to protect another from unlawful force. Modern law generally asks whether the defendant reasonably believed intervention was necessary and proportionate.

Older approaches sometimes required the defender to “stand in the shoes” of the person defended. Under that view, if the person defended had no right of self-defense, the intervenor had no defense even if mistaken. Modern rules are more likely to protect reasonable mistakes.

For example, if Dana reasonably believes Riley is being unlawfully attacked and uses proportionate force to protect Riley, defense of others may apply even if Dana later learns the situation was more complicated.

A person may use reasonable nondeadly force to protect property from unlawful interference. But deadly force is generally not allowed solely to protect property.

The law values human life over property. A homeowner may use reasonable force to stop a thief from taking a bicycle, but may not set a deadly trap to kill trespassers or shoot someone merely to prevent theft of a replaceable object.

Deadly force may be justified if the property invasion also threatens personal safety, such as a violent home invasion. In that situation, the defense is better understood as defense of persons or habitation, not mere defense of property.

Necessity is a justification defense. It applies when the defendant commits a lesser harm to prevent a greater imminent harm.

The classic example is breaking into a cabin during a blizzard to avoid freezing to death. The defendant technically commits trespass or burglary-like entry, but the act may be justified because it prevents a greater harm.

Necessity usually requires that the harm avoided be greater than the harm caused, that the danger be imminent, that there be no reasonable legal alternative, and that the defendant not be responsible for creating the emergency.

Traditionally, necessity was not available for intentional homicide. A person could not kill an innocent person and claim it was necessary to save several others, although modern discussions sometimes complicate this point. Students should apply the rule given.

Necessity is often called the “choice of evils” defense. The defendant chooses the lesser evil in an emergency.

Duress is usually an excuse defense. It applies when the defendant commits a crime because another person threatens imminent death or serious bodily harm unless the defendant complies.

Duress generally requires a threat by a human actor, imminent danger, reasonable fear, no reasonable opportunity to escape, and no fault by the defendant in creating the situation.

Suppose a robber points a gun at Alex and says, “Drive this getaway car or I will kill you right now.” Alex drives under the threat. Duress may excuse Alex’s conduct, depending on the offense and jurisdiction.

Duress traditionally is not a defense to intentional murder. The law may sympathize with the defendant’s terror, but many jurisdictions refuse to excuse killing an innocent person even under threat. Modern approaches vary.

Mistake of fact may defeat criminal liability when it negates the required mental state.

For specific-intent crimes, even an unreasonable mistake may sometimes negate the required intent if it is honest. If larceny requires intent to steal property of another, a defendant who honestly believes the property belongs to him may lack intent to steal, even if the belief is unreasonable.

For general-intent crimes, many jurisdictions require the mistake to be both honest and reasonable. An unreasonable mistake may not excuse.

For strict-liability offenses, mistake of fact usually is not a defense as to the strict-liability element. If a statute treats age as strict liability in statutory rape, a reasonable mistake about age may not matter unless the statute allows it.

Mistake of law is generally not a defense. The ordinary rule is that ignorance of the law excuses no one. A person who knows the facts but does not know those facts are illegal usually remains liable.

For example, a defendant who knowingly carries a prohibited weapon cannot usually defend by saying, “I did not know the statute made this illegal.”

There are limited exceptions. Mistake of law may matter when the statute requires knowledge of the law or legal status as an element. It may also matter when the defendant reasonably relies on an official statement of law from an authorized source that later turns out to be wrong. Some crimes require a specific intent to violate a known legal duty, though this is unusual and statute-dependent.

Mistake of law can also overlap with mistake of fact. If a defendant misunderstands a legal concept that affects property ownership, the analysis may be difficult. The safest exam approach is to identify whether the mistake negates a required mental state or merely reflects ignorance that the conduct is criminal.

Intoxication can be voluntary or involuntary.

Voluntary intoxication occurs when the defendant knowingly consumes alcohol, drugs, or another intoxicating substance. It is generally not a complete defense. However, in some jurisdictions, voluntary intoxication may negate specific intent if the defendant was so intoxicated that the required specific purpose could not be formed.

For example, burglary requires intent to commit a felony inside at the time of entry. If a defendant was so intoxicated that he entered without any such intent, voluntary intoxication may be relevant. But it usually will not excuse general-intent crimes, recklessness, or strict-liability offenses.

Involuntary intoxication occurs when the defendant is intoxicated without knowing, without consent, under coercion, or through unexpected reaction to prescribed medication in some circumstances. Involuntary intoxication may be treated more like insanity if it prevents the defendant from understanding the nature or wrongfulness of conduct.

Insanity is an excuse defense based on mental disease or defect. It asks whether the defendant’s mental condition was so severe at the time of the offense that criminal punishment is inappropriate under the governing test.

Jurisdictions use different insanity tests.

The M’Naghten test asks whether, because of mental disease or defect, the defendant did not know the nature and quality of the act or did not know the act was wrong.

The irresistible impulse test asks whether the defendant was unable to control conduct because of mental disease, even if the defendant understood the act.

The Model Penal Code test asks whether, because of mental disease or defect, the defendant lacked substantial capacity to appreciate the criminality or wrongfulness of conduct or to conform conduct to the requirements of law.

Some jurisdictions use narrower tests. Others have modified or abolished parts of the insanity defense. Students must apply the rule supplied.

Insanity is different from incompetency to stand trial. Insanity concerns the defendant’s mental state at the time of the offense. Competency concerns whether the defendant can understand proceedings and assist counsel at the time of trial.

Infancy concerns the criminal responsibility of children. Traditional common law used age presumptions. Very young children were conclusively presumed incapable of crime. Older children within a middle range were presumed incapable unless the prosecution proved capacity. Older adolescents could be treated more like adults.

Modern juvenile law varies. Many jurisdictions handle young offenders in juvenile court, use minimum ages of prosecution, or allow transfer to adult court for serious offenses. The underlying principle is that children may lack the maturity, judgment, and culpability associated with adult criminal responsibility.

For exam purposes, apply the age rule or statute provided.

Entrapment applies when law enforcement induces a person to commit a crime the person was not predisposed to commit.

The dominant subjective approach asks whether the defendant was predisposed to commit the offense. If the government merely provides an opportunity to a willing person, entrapment usually fails. If the government pressures, threatens, manipulates, or repeatedly persuades an otherwise unwilling person, entrapment may apply.

An objective approach focuses more on police conduct, asking whether the government’s methods would induce a normally law-abiding person to commit the crime.

Entrapment usually requires government involvement. A private person’s persuasion generally does not create entrapment unless acting as a government agent.

A strong Criminal Law answer should proceed in an organized sequence.

First, identify the offense or offenses. Do not write generally about wrongdoing. Name the crime.

Second, break each offense into elements. Separate actus reus, mens rea, attendant circumstances, result, and causation.

Third, analyze the act requirement. Was there a voluntary act, legally required omission, or possession?

Fourth, analyze mens rea. Apply common-law terms or Model Penal Code mental states as required.

Fifth, address concurrence. Did the mental state exist at the time of the act?

Sixth, analyze causation for result crimes. Discuss actual cause, proximate cause, and intervening events.

Seventh, grade the offense. For homicide, distinguish murder, manslaughter, felony murder, and causation. For property crimes, match precise common-law elements. For inchoate crimes, distinguish solicitation, conspiracy, and attempt.

Eighth, analyze parties. Ask what each actor did, what each intended, and whether accomplice, conspiracy, Pinkerton, or accessory liability applies.

Ninth, raise defenses. Consider self-defense, defense of others, defense of property, necessity, duress, mistake, intoxication, insanity, infancy, and entrapment.

Finally, conclude carefully. Criminal Law often supports alternative charges. State the strongest offense, the weaker alternatives, and the best defense.

Several issues arise.

Alex may be guilty of solicitation when he asked Blake to burn the store. Alex and Blake may be guilty of conspiracy when they agreed. Blake likely committed arson if the elements are satisfied. Alex may be an accomplice to arson because he intentionally provided gasoline and the alarm code.

The guard’s death raises homicide. Blake may be liable for murder if the killing shows intent to inflict serious bodily injury, depraved-heart recklessness, or felony murder based on arson. Alex’s homicide liability depends on accomplice principles, felony murder, Pinkerton liability, and foreseeability. If death during arson was foreseeable and within the governing felony-murder rule, Alex may face murder liability even if he did not desire death.

Defenses seem weak. Necessity does not apply because Alex and Blake created the danger. Duress is absent unless another person threatened them. Mistake is not apparent. If Blake panicked, that may affect grading, but panic alone does not excuse striking the guard with deadly force.

This hypothetical shows why Criminal Law is cumulative. Elements, inchoate crimes, parties, homicide, causation, and defenses all interact.