The insanity defense isn't used nearly as much as you seem to think it is, and never to the defendant's benefit. Do you think mental hospitals are nice places?

The insanity defense isn't used nearly as much as you seem to think it is, and never to the defendant's benefit. Do you think mental hospitals are nice places? It isn't a "get out of jail free" card. It's a "stay in mental hospital instead, probably longer" card. Insanity pleas exist because the purpose of the justice system is, in principle, to improve society -- not to punish -- and prisons are in any case not equipped to incarcerate the insane.