The author considers the merits of the insanity defense in light of three premises. First, a defendant's sanity must be taken into account both in assessing culpability and in assigning punishment for a crime. Second, all members of society must be protected against harmful acts. And third, it is the responsibility of psychiatrists to assess, but not to predict, the existence of mental illness. After briefly discussing the limitations of expert testimony and the adversarial demands of the judicial system, the author concludes that the insanity defense should be retained but altered, and that psychiatrists should bear the burdens of advocating for the mentally ill.