19.2 Responsibility & Defenses: Insanity, Intoxication, Infancy, Justification & Excuse

19.2 Responsibility & Defenses: Insanity, Intoxication, Infancy, Justification & Excuse

Defenses fall into two groups. Responsibility defenses (insanity, intoxication, infancy) ask whether the defendant can fairly be held accountable. Justification and excuse defenses (self-defense, necessity, duress, entrapment) ask whether conduct that otherwise satisfies a crime's elements should be punished. NCBE's outline tests both.

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Affirmative Defenses

1. Self-Defense and Defense of Others

• Non-Deadly Force: A person may use non-deadly force whenever they reasonably believe that such force is necessary to protect against the imminent use of unlawful force.
• Deadly Force: A person may use deadly force only if they reasonably believe that such force is necessary to prevent imminent death or great bodily harm, or to prevent the commission of a violent felony.
• Retreat Rules:
  • Majority Rule: There is no duty to retreat; a non-aggressor may stand their ground anywhere they have a legal right to be.
  • Minority Rule: Requires retreat before using deadly force if retreat can be accomplished with complete safety, except inside one's own home under the Castle Doctrine.
• Initial Aggressor: An initial aggressor cannot claim self-defense unless: (a) they withdraw completely and communicate that withdrawal; or (b) the other party suddenly escalates a non-deadly conflict into a deadly fight without opportunity to retreat.

2. Defense of Property

• A person may use reasonable non-deadly force to protect their property.
• Deadly force is NEVER permitted solely to defend property (Katko v. Briney). Spring guns, automated lethal traps, or armed booby traps to protect unoccupied property constitute unlawful deadly force.

3. Insanity: The Four Tests

4. Duress

• Duress is an affirmative defense where the defendant committed the crime under a reasonable belief of an imminent threat of death or serious bodily injury to the defendant or another person (some jurisdictions limit third-party threats to close family members).
• Absolute Exception: Duress is never a defense to intentional homicide (murder). A defendant cannot kill an innocent person to save their own life.

5. Entrapment

Entrapment requires proof of two cumulative prongs:

1. The criminal design originated with law enforcement officers or government agents; and
2. The defendant was not predisposed to commit the crime prior to government contact.

• If the defendant was readily predisposed to commit the crime, the entrapment defense fails even if the police provided the opportunity or materials.

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More on Responsibility & Defenses

Mental Disorder

• Federal test: Under the Insanity Defense Reform Act, a federal defendant must prove by clear and convincing evidence that, because of a severe mental disease or defect, he was unable to appreciate the nature and quality or the wrongfulness of his acts (18 U.S.C. § 17).
• Burden and scope: States may place the burden of proving insanity on the defendant and may limit the use of mental-health evidence to the insanity defense (Clark v. Arizona, 2006). Due process does not require a state to adopt an insanity test that turns on the defendant's capacity to know that an act was morally wrong (Kahler v. Kansas, 2020).
• Diminished capacity: Some jurisdictions allow evidence of mental impairment short of insanity to show that the defendant lacked a specific intent or premeditation; others do not.
• After acquittal: A defendant found not guilty by reason of insanity may be committed until no longer mentally ill or dangerous, even beyond the maximum prison sentence for the crime (Jones v. United States, 1983).
• Competency is different: Insanity concerns the defendant's mental state at the time of the crime; competency to stand trial concerns the defendant's present ability to understand the proceedings and assist counsel (Section 23.1).

Intoxication

Infancy

Modern statutes typically give juvenile courts jurisdiction over young offenders and set ages at which a juvenile may be tried as an adult.

Defense of Others and Law Enforcement

• Defense of others: Most jurisdictions allow a defender to use the force that reasonably appears necessary to protect a third person. A minority "alter ego" rule makes the defender liable if the person defended was not actually entitled to use force.
• Police use of deadly force: Police may use deadly force to prevent the escape of a fleeing suspect only if they have probable cause to believe the suspect poses a significant threat of death or serious physical injury (Tennessee v. Garner, 1985).
• Resisting arrest: Modern statutes generally prohibit using force to resist even an unlawful arrest by a person known to be a police officer.

Necessity

• Elements: The defendant reasonably believed the conduct was necessary to avoid an imminent harm greater than the harm caused, had no adequate legal alternative, and did not substantially create the emergency; the legislature must not have precluded the defense.
• Limits: At common law, necessity never justifies an intentional killing (Regina v. Dudley & Stephens, 1884), and economic necessity is not recognized. An escaped prisoner claiming necessity must have made a bona fide effort to surrender once the danger passed (United States v. Bailey, 1980).
• Necessity versus duress: Necessity involves pressure from natural or physical circumstances and justifies the conduct; duress involves human threats and excuses it.

Duress and Entrapment Details

• Duress: Most jurisdictions require that the threat be present and unavoidable, with no reasonable opportunity to escape or seek help, and deny the defense to a defendant who recklessly placed himself in the situation. The MPC asks whether a person of reasonable firmness would have been unable to resist. In federal court, the defendant bears the burden of proving duress by a preponderance of the evidence (Dixon v. United States, 2006).
• Entrapment—subjective test (majority and federal): The government must prove the defendant was predisposed to commit the crime before government agents first approached him. After 26 months of repeated government mailings, the government failed to prove that a defendant who ordered child pornography had been predisposed (Jacobson v. United States, 1992).
• Entrapment—objective test (MPC and a minority of states): The question is whether the government's methods would likely induce an ordinary law-abiding person to commit the crime.
• Private persons: Inducement by a private person who is not acting for the government is not entrapment.

Consent

Consent is a defense when lack of consent is an element of the crime—as in rape or larceny—or when the harm is minor or part of a lawful activity such as a sporting event. A person generally cannot consent to death or serious bodily injury.