Case Update: Definition of Insanity up to the States

On Thursday, the U.S. Supreme Court, in the case of Clark v. Arizona, upheld Arizona’s insanity test statute, holding that due process does not prohibit Arizona’s use of an insanity test stated solely in terms of the capacity to tell whether an act charged as a crime was right or wrong. In Clark, a 17-year-old undisputed paranoid schizophrenic shot and killed a Flagstaff police officer. Lawyers for the defense argued that the Defendant believed the police officer he killed was an alien from outer space. They argued that he belonged in a mental hospital rather than a state prison. Prosecutors introduced evidence at trial that Clark had earlier told a friend that he was thinking of creating a disturbance to attract police officers to a particular location so he could shoot them dead. They said the murder of a law-enforcement officer was therefore a premeditated act.

The traditional English rule insanity test established in the landmark M’Naghten case asks about cognitive capacity: whether a mental defect leaves a defendant unable to understand what he was doing. The test also has a second part, an alternative basis for recognizing a defense of insanity, testing moral capacity: whether a mental disease or defect leaves a defendant unable to understand that his action was wrong. The Arizona Legislature at first adopted the full M’Naghten statement, but later dropped the first test, and decided to just go with the later. Currently, the test in Arizona reads that a defendant will not be adjudged insane unless he demonstrates that at the time of the crime, he was afflicted with a mental disease or defect of such severity that he did not know the criminal act was wrong. In reviewing the tests of other states, the Court concluded that the varied tests by each state made clear that no particular formulation has evolved into a baseline for due process, and that the insanity rule, like the conceptualization of criminal offenses, is substantially open to state choice.The opinion can be read at: http://www.law.cornell.edu/supct/html/05-5966.ZS.html