M'Naghten's Case

M'Naghten's Case (1843) established a legal standard for insanity in criminal law. It involved Daniel M'Naghten, who believed government agents were out to harm him and, in a panic, murdered the Prime Minister’s secretary, mistaking him for an agent. The court ruled he was unable to understand the nature of his act or recognize it as wrong due to a mental defect. This case set the "M'Naghten Rule," which states that a person is not criminally responsible if, at the time of the crime, they were suffering from a mental illness that prevented them from understanding the act or knowing it was wrong.