Our family had an ex-husband who scrawled “You are a whore,” on the wall of her place of employment. He also shot out the window in her living room. Finally, he caught his ex-wife’s lawyer on the sidewalk and almost cut off his head with a boning knife. The murder made big headlines on TV and newspapers. He got off from a Capital murder conviction with a mental illness defense. Letters to the editor of my newspaper were filled with outrage at the acquittal. It seems that if your crazy enough, you get three meals and a room at a mental hospital.
It has to be a possible defense in our system, because whatever you may think about individual cases, sometimes people really ARE crazy and not fully responsible for their acts.