It's always nice to see the Supremes wrestle with insanity in the American way of life, and not do so well.
Under the classic McNaughton (M'Naghton) definition of insanity, the accused is entitled to an acquittal on insanity grounds if s/he doesn't know "the nature and quality" of the act or "that it was wrong," i.e. didn't know right from wrong.
Are these distinguishable? Suppose God tells you to kill someone who is bad and you think this is right. You're insane, right?
So, suppose, on cross-examination you admit that you know that killing a good person is wrong but that God told you to kill X because he was bad. You have thus showed that you know right from wrong, right? Wrong?
The Supremes are having a little problem sorting this out in a case where the accused killed a cop claiming he was a Martian. Not so funny, is it.
Check out Charles Lane's report, Washington Post, below: