an believed that certain people, including the British prime minister and the Pope, were conspiring against him. He decided to assassinate Peel but killed Peel's secretary, Drummond, instead. The issue of criminal insanity was raised at trial and studied closely by both sides. McNaughton was acquitted by the jury and sent to Broadmoor, a mental institution, where he later died. The case led to the establishment of a test for insanity known as the McNaughton Rule, as detailed by British Lord Chief Justice Tindal:
The jury ought to be told in all cases that every man is to be presumed to be sane, and to possess a sufficient degree of reason to be responsible for his crimes, until the contrary be proved, that, at the time of the committing of the act, the party accused was laboring under such a defect of reason, from disease of the mind, as not to know the nature and quality of the act he was doing, or if he did know it, that he did not know he was doing what was wrong (Gerber 24).
More generally, Tindal said that the jury had to ask whether the accused man knew the difference between right and wrong at the time of his or her crime.
In practice, one of the first issues raised at trial is whether the defendant has the necessary competency to stand trial at all. A 1960 Supreme Court decision detailed the factors to be considered in an incompetency hearing in terms of the ability of the defendant to participate in the legal process. By the end of the 1960s, incompetency determinations were tied to appropriate questions of capacity to understand the charges, the ability to assist counsel, and sufficient mental stability to withstand the rigors of a criminal trial. Fewer people were now found to be incompetent (Maeder 127-128). The result of a wide variety of cases in this area was that the law was somewhat confusing. Fewer people were found to be incompetent, and those who were spent less time in the hospital. Some could be...