Temporary Insanity: The Strange Life and Times of the Perfect Defense

Abstract

The temporary insanity defense has a prominent place in the mythology of criminal law. Because it seems to permit factually guilty defendants to escape both punishment and institutionalization, some imagine it as the “perfect defense.” In fact, the defense has been invoked in a dizzying variety of contexts and, at times, has proven highly successful. Successful or not, the temporary insanity defense has always been accompanied by a storm of controversy, in part because it is often most successful in cases where the defendant’s basic claim is that honor, revenge, or tragic circumstance – not mental illness in its more prosaic forms – compelled the criminal act. Given that the insanity defense is considered paradigmatic of excuse defenses, it is puzzling that temporary insanity also functions as a sort of justification defense. This Article seeks to solve that puzzle by canvassing the colorful history and the conceptual function of the defense. Ultimately, it argues that temporary insanity should be viewed as an equitable doctrine that provides relief where the traditional legal rules exclude or are inadequate to the defendant’s particular circumstances. Because the temporary insanity defense permits juries to resolve difficult cases in a manner consistent with the deep purposes of the criminal law, it is misleading to conceptualize that defense as merely a nullification doctrine.

Keywords: criminal law, mental health, insanity, defenses, insanity defense, nullification doctrine, mental illness, excuse defenses, temporary insanity, equitable doctrine

JEL Classification: K00, K14, K40, K41