Depends what mental case is defined as.
Mental case means someone who acts without reason and has a legit mental disorder. Terrorists often act in a way that may be rational to accomplish their goals, even if their goals are crazy. They knew what they were doing and did it for a reason. That is not a mental case. It is a bad person with bad motives.
there is a reason that all criminals cannot use the insanity defense. People do bad things often when they are not insane…