A U.S. Supreme Court Justice’s comment on an important criminal law rule is instructive.
In January 1843, Daniel M’Naghten, suffering from delusions of persecution, had a fancied grievance against Prime Minister Robert Peel. He traveled to London to assassinate him but mistakenly shot Peel’s secretary, Edward Drummond, who died from the wound several days later.1
M’Naghten was found not guilty by reason of insanity. As Lord Chief Jus