Insanity Defense

Insanity Defense, the principal legal doctrine permitting consideration of mental abnormality in assessing criminal liability. The roots of the defense stretch back to Greece before the birth of Christ. In the English‐speaking world, written evidence of cases in which pardons were granted on the ground of “madness” exists from medieval England. In the United States, the insanity defense has always been an accepted part of criminal law doctrine. Today most states define insanity as a mental impairment that impedes a person's ability to understand the wrongfulness of his or her act (the “cognitive” prong) and a number of states also permit a defense when the disability impairs the person's ability to control the act (the “volitional” prong). Nonetheless, the defense has been controversial, because it allows those who commit heinous crimes to escape criminal punishment (although those who are acquitted are still usually committed to a hospital for an indeterminate period).

The Supreme Court has proceeded cautiously in this area, with its few relevant decisions only indirectly addressing the proper formulation of the test for insanity. In Leland v. Oregon (1952), the Court held that, if a state chooses to adopt the defense, the Constitution does not mandate use of a test any broader than the historical M'Naghten formulation (a test devised by the English House of Lords in 1843 that focuses solely on “cognitive” impairment). The Court indicated that, given the state of knowledge at the time, a “volitional” excuse was not constitutionally necessary. Two later Court decisions, although not directly relevant to the insanity defense, bolstered this aspect of Leland. In Robinson v. California (1962), the justices held that the Eighth Amendment (which bars “cruel and unusual punishment”) prohibits punishing someone merely for being addicted to heroin. In Powell v. Texas (1968), five members of the Court interpreted this holding to mean that “the chronic alcoholic with an irresistible urge to consume alcohol should not be punishable for drinking or for being drunk” (p. 549). But the majority in Powell also held that one could be punished for being drunk in public. Thus, analogously, while a state would be forbidden from punishing a person merely for being mentally ill, it would not be barred by Robinson or Powell from punishing a mentally ill person who committed a crime, and whose only defense is that the impulse to commit it was “irresistible.”

Further evidence that the Court may not find the insanity defense to be an essential aspect of criminal liability comes from its treatment of the burden of proof relating to the defense. Leland also held that the state may require the defendant to prove insanity beyond a reasonable doubt. Almost two decades later, the Court called into question this portion of Leland when it held in In re Winship (1970) that the prosecution must prove beyond a reasonable doubt “every fact necessary to constitute proof of the crime with which [the defendant] is charged” (p. 364). But in Rivera v. Delaware (1976), the Court later dismissed, for want of a substantial federal question, an appeal of a conviction under an instruction placing the burden of proving insanity on the defendant by a preponderance of the evidence. At least five states have replaced the insanity defense with a rule that evidence of mental illness may be admitted only on the narrow issue of whether the defendant intended to commit the crime (which is usually the case even for those offenders who are severely mentally ill). Despite its willingness to permit significant limitations on the insanity defense, the Court's reaction to these laws, which in essence abolish the defense, is not entirely predictable. On the one hand, in Rivera v. Delaware (1976) the Court dismissed, for want of a substantial Federal question, an appeal of a conviction under an instruction placing the burden of proving insanity on the defendant. Because the Court, in Winship, had earlier held that the prosecution must bear the burden of proving “every fact necessary to constituting proof of the crime … charged” (p. 364), Rivera's holding suggests that sanity is not a necessary aspect of guilt. On the other hand, in Egelhoff v. Montana (1996), a primary reason the Court gave for explaining its holding that a state does not violate the Due Process Clause when it abolishes the intoxication defense was that the latter defense is of “recent vintage” (p. 51). In contrast, as noted above, the heritage of the insanity defense is ancient, a fact that might influence the Court if and when it confronts a case raising the constitutionality of abolishing the defense.

Bibliography

Gary I. Melton , Psychological Evaluations for the Courts: A Handbook for Mental Health Professionals and Lawyers, 2d ed. (1997), ch. 8.

Christopher Slobogin