"By the fifteenth century.If the defendant had committed the act, they had to convict; if he was insane, or a minor, or had killed in self-defense, they could recommend mercy." (Maeder 5).
In the sixteenth century, however, the jury gained the power to enter a "Special Verdict" if they felt the case warranted. By the seventeenth century, the insanity defense was firmly in place, thus this plea was commonly accepted. The insanity defense reflects a compromise on the part of society and the law. On the one hand, society believes that criminals should be punished for their crimes; on the other hand, society believes that people who are ill should receive treatment for their illness. The insanity defense is the compromise: Basically, it reflects society's belief that the law should not punish defendants who are mentally incapable of controlling their conduct.
In the eighteenth century, the legal standards for the insanity defense were varied. Some courts looked to whether the defendant could distinguish between good and evil, while others asked whether the defendant "did not know what he did." By the nineteenth century, it was generally accepted that insanity was a question of fact, which was left to the jury to decide. Today in twentieth century, we still have great qualms about the insanity defense.
Although we no longer debate what to do with our insane community, we do debate if one is insane. Indeed, we have even created excuses for the sane to be "Temporarily Insane", and all of this is highly arguable. Seventeen states now allow verdicts of "Guilty but Mentally ill", which holds a defendant responsible while providing for mental treatment in prison. at least three states - Montana, Idaho, and Utah - have abolished the insanity defense entirely. Thus the trend that one can escape severe punishment through the insanity defense is becoming less and less feasible. This defense is seldom used and rarely successful today.
