Insanity Defense

I believe that the ability to plead insanity is not a good law, in a case that the citizen has commited murder i do not believe that the citizen should be able to plead insanity, the person that commited the crime should not be able to plead insanity because in order to be able to commit murder you have to know what is going on during that time unless it is a "heat of passion" crime.
No, i think that in criminal cases the commiter should not be able to plead insanity because in most cases the commiter has planned out the crime for a period of time and in order to go through with the crime, especially if the commiter has a past record in crime. Insanity is constituted by having a psychiatrist look at the patients history and check if they have any background of insanity and make them go through multiple tests so they can not fake there plead.
My opinion on the Andrea Yates case is that if she is able to kill all five of her children then she should not be able to go away from the facility she is in i dont care if its only during the day or to see her family, i believe she should be in a higher level mental facility in order to make sure she is taking her medicine and doing the right things she should be doing.