What are the arguments for and against the insanity plea?

Arguments for-


Basically there is only one very strong argument for its use, and that is fairness to the mentally ill. The idea of punishment is based on the philosophy that a person should receive retribution for doing something wrong as well as given reason not to do it again in the future. However, in the case of the mentally ill, neither of these is upheld. While the person did do something wrong, can they be blamed if they didn't know what they were doing, or if they knew what they were doing but couldn't stop themselves.


Arguments against-


First, people worry that somebody who is not insane will be found innocent and sent to a mental hospital instead of a prison. Many reforms to the system in America occurred after the John Hinckley case, in which Hinckley attempted to assassinate the president and was found innocent (Not Guilty Reason Insanity).


Second, courts have long grappled with the problem of defining insanity. In a court mental illness is not based on the current mental state of the defendant but rather their mental state when the crime was committed. Furthermore, very little medical evidence is used when a court is determining whether somebody is insane or not. For example, somebody may be diagnosed with schizophrenia, but that diagnosis often does not play a role in the court proceedings. Often courts generally try to answer questions like "Did the defendant know what they were doing was wrong?" or "If they knew it was wrong, could they stop themselves."


It should also be pointed out that before the case is even brought to court, the person must be found fit to stand trial. The requirements for this are more or less that the defendant must know they are going to court, what charges they are going on, and understand who critical members of the court are (the judge, defense attorney, etc.). If they are not found fit to stand trial they are sent to a mental institution and receive treatment until they are deemed fit.


To try and compensate for some of the error involved in trial, many states have incorporated a Guilty But Mentally Ill plea. The GBMI essentially is a guilty plea that acknowledges the defendant's mental state and allows them to receive psychological attention in prison.


Currently only 4 states do not have the insanity plea (Montana, Utah, Idaho, and Kansas). All four of these states have GBMI verdicts.