This is “End-of-Chapter Material”, section 6.4 from the book Introduction to Criminal Law (v. 1.0).
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The federal government and every state except Montana, Utah, Kansas, and Idaho recognize the insanity defense. A not guilty by reason of insanity verdict is an acquittal for the offense. The policy supporting the insanity defense is the lack of deterrent effect when punishing the legally insane. Four insanity defenses are recognized in the United States: M’Naghten, irresistible impulse, substantial capacity, and Durham. The M’Naghten insanity defense is cognitive and excuses criminal conduct when the defendant is suffering from a mental defect or disease that prevents the defendant from knowing the nature or quality of conduct or from knowing that conduct is wrong. The irresistible impulse insanity defense adds a volitional component and excuses conduct the defendant cannot control because of a mental defect or disease. The substantial capacity test was created by the Model Penal Code and softens the requirements to substantial, rather than total, capacity to appreciate the criminality of conduct or to conform conduct to the law. The Durham insanity defense is recognized only in New Hampshire, and excuses conduct that is the product of or caused by a mental disease or defect. Jurisdictions vary as to the burden of proving insanity. All jurisdictions require the defendant to rebut a presumption that he or she is sane; some also require the defendant to persuade the trier of fact that he or she is legally insane to a preponderance of evidence or clear and convincing evidence (which is a higher standard than preponderance of evidence).
A minority of jurisdictions recognizes diminished capacity and the syndrome defense when the defendant cannot form the requisite criminal intent for the offense because of a mental impairment. The criminal defendant must also be mentally competent to stand trial, which means the defendant can understand the charges brought against him or her and can assist in any defense. Some jurisdictions recognize a guilty but mentally ill verdict, which does not exonerate the defendant, but provides for mental health treatment while incarcerated. Temporary insanity is also a defense in some jurisdictions and does not differ from the insanity defense except for the duration of the mental defect or disease.
The infancy defense excuses conduct when the defendant is too young to form criminal intent for the offense. The infancy defense is generally not available in juvenile adjudications, so it is rarely asserted because most youthful defendants are under the jurisdiction of juvenile courts. Juvenile courts can waive this jurisdiction and allow for an adult criminal prosecution under certain circumstances, considering the criteria of the nature of the offense, the sophistication it requires, the defendant’s prior criminal history, and the threat the defendant poses to public safety.
Other excuse defenses are intoxication, ignorance, and mistake. Voluntary intoxication is frowned on as a defense, but will occasionally excuse conduct if it negates certain high-level criminal intent requirements. Involuntary intoxication, which is intoxication achieved unknowingly, or under duress or fraud, is more likely to provide a defense if it affects the defendant’s capacity to form criminal intent. Ignorance of the law is not a defense because individuals are expected to know the laws of their jurisdiction. Mistake of law, which means the defendant does not know conduct is illegal, functions as a defense if the mistake is based on a judicial opinion or statute that is later overturned. Mistake of law is not a defense if the mistake is rooted in incorrect legal advice from an attorney. Mistake of fact is a defense if the facts as the defendant believes them to be negate the intent required for the offense.
Entrapment is also a defense in every jurisdiction. Most states and the federal government recognize the subjective entrapment defense, which focuses on the defendant’s predisposition, and does not excuse conduct if the defendant would have committed the crime without law enforcement pressure. In a subjective entrapment jurisdiction, the defendant’s criminal record is admissible to prove predisposition to commit the crime at issue. Objective entrapment is the Model Penal Code approach and excuses conduct if the pressure by law enforcement would induce a reasonable, law-abiding person to commit the crime. The defendant’s criminal record is not admissible to show predisposition in an objective entrapment jurisdiction because the focus is on law enforcement tactics, not the defendant’s nature.
You are a well-known private defense attorney with a perfect record. Read the prompt, review the case, and then decide whether you would accept or reject it if you want to maintain your level of success. Check your answers using the answer key at the end of the chapter.