Insanity defense

The ability to plead insanity in my eyes is not a good law at all. It is common knowledge that this defense is overused and taken advantage of by people looking for an easy way out of a crime. Even if the people are truly insane then they are the last people i want to see out in the streets in a few months anyway. Also, the point of the judicial system should be to look at each crime without any emotional connection and with this insanity defense, it provides a moral check that has no place in the system.
What constitutes insanity in this country is not knowing the difference of right and wrong. That's it. And this rule has been in place since 1843, McNaughton rule. That seems a little outdated to me. There should be multiple tests by multiple specialists in the psychology field to decide if this person is actually crazy.
The person who drowned her 5 kids and got off with insanity after a history in and out of institutions, got away with living in an open metal help facility. She should have received capital punishment for her actions because she thought about doing this more multiple years and after she did it, she got away with it basically. I personally don't care if she is crazy enough to kill all of her kids because she thought she was a bad mother, I never want to see her in America ever again and I'm pretty sure no other Americans want to see her here either. For that reason, she should receive capital punishment or deported to some other country. That way we don't have to pay for her shelter, food, and water, like we are doing now with taxpayers money.