Two fundamentally distinct questions are intertwined in discussions of the insanity defense. One is essentially dispositional and looks forward in time: what should be done with mentally disordered offenders, including those who are acquitted by reason of insanity, to minimize the risk of future reciditism? The other concerns the moral issue of responsibility, a question looking backward to the offender's mental condition at the time of the offense. Among the most fundamental principles of criminal law are that criminal punishment should be imposed only on those who are blameworthy and that even blameworthy offenders should not be subjected to punishment which is disproportionate to the degree of their culpability.

I want to address most of my prepared remarks to the question of responsibility. I will argue, in summary, that you should reject the sweeping proposals to abolish the insanity defense in favor of proposals to narrow it and shift the burden of proof to the defendant. The core of the defense must be retained, in my opinion, because some defendants afflicted by severe mental disorder who are out of touch with reality and are unable to appreciate the wrongfulness of their acts cannot justly be blamed and do not therefore deserve to be punished. The insanity defense, in short, is essential to the moral integrity of the criminal law.

Richard J. Bonnie, The Insanity Defense: Proposals for Reform, 2 Developments in Mental Health Law 21–22, 28 (1982).