irment -- to determine whether or not an individual accused of a crime was mentally impaired at the time the crime was committed (Lashbrook, 2004). This Rule states that a person "ais not guilty of a crime if, at the time of the crime, they either didn't know what they were doing or didn't know that what they were doing was wrong (Insanity defense, 2005, p. 3)." The defense is therefore based on a principle that punishment is only reasonable if and when the defendant is capable of distinguishing right from wrong.
In the United States, the Supreme Court has proceeded cautiously in this area and has directed much of its attention to the proper formulation of a test for insanity (Hall, 1992). In modern times, insanity has been defined as a mental impairment that either impedes a person's ability to understand the wrongfulness of an action (the cognitive prong) or to control the act (the volitional prong). For example, in the case of Leland v. Oregon (1952), the Court held that if a state chooses to adopt this defense, the U.S. Constitution does not mandate the use of a test any broader than the historical M'Naghten formulation (Hall, 1992).
Later, the Court bolstered this aspect of Leland, suggesting that a volitional excuse was not constitutionally necessary. In Robinson v. California (1962), the Court held that the Eighth Amendment barring cruel and unusual punishment prohibits punishing someone for merely being addicted to heroin. In Powell v. Texas (1968), a majority of the justices of the Court interpreted this holding to mean that the chronic alcoholic should not be punished for drinking or being drunk, but added that one could be punished for being drunk in public. What this suggests, said Hall (1992), is that the Court believes that a state should be forbidden to punish a person merely for being mentally ill, but not necessarily prohibited from punishing a mentally ill person for committing a crime.
It is here,...