Actually, pleading insanity does not work very well.
One must be rich and crazy, like John Hinckley, Jr. and John DuPont, not poor and crazy, like Sgt. Timothy McVeigh (ret.).
I imagine that most mass murderers really are psychopathic, but only from a clinical, not a legal, point of view.
In one month, US troops public burned Korans, peed on corpses and murdered defenseless women and children. It is time to go.