Not Guilty By Reason of Insanity?
The insanity defense is a defense by excuse. The defendant argues that they should not be held criminally responsible for breaking the law because they were mentally ill or mentally incompetent at the time of their alleged criminal action. The thought behind this is that someone suffering from a mental disorder is not capable of knowing or choosing right from wrong so they should not be punished. When this is the case, they are pleading not guilty by reason of insanity or NGRI. In 1843 there were guidelines made for evaluating criminal responsibility for defendants claiming to be insane by the British courts. This defense became known as M’Naghten Rules. Daniel M’Naghten was a Scottish woodcutter who murdered the secretary to the Prime Minister, Sir Robert Peel, when he was trying to assassinate the prime minister. M’Naghten believed that the prime minister was to blame for all of his problems. A jury acquitted him after they heard testimony by nine witnesses who all said he was insane. He was found not guilty by reason of insanity. The common law courts said that a person should not be held responsible for his actions if due to his mental disease or defect, he did not know that his act would be wrong or did not understand the nature of his actions. The M’Naghten rule was embraced with almost no modification by American courts and legislatures for more than 100 yrs, until the mid-20th century. In 1998, 25 states plus the District of Columbia still used versions of the M’Naghten rule to test for legal insanity. The key is that the defendant could not appreciate the nature of his actions during the commission of the crime. In the United States there is no temporary mental impairment, it falls under the category of a mitigating factor referred to as “diminished capacity”. A mitigating factor which can include conditions not eligible for the insanity defense such ...