It seems to me that there are two problems here. The first is that we suck at finding/handling the mentally ill. These mass shootings are rare, but the connection between crime and mental illness in this country is anything but.
The second issue is of course that we do a piss-poor job of keeping guns away from the people they need to be kept away from.
Ideally both issues should be tackled.
Do they get to plead insanity in court? Should they be sent to mental hospitals or prisons?
I'm not being facetious, I'm asking seriously, what definition of sanity are we running on here?
I don't care if they are placed in prisons or mental hospitals, so long as they are not set free. People who are interested in revenge will likely prefer they be sent to prisons, and those interested in helping the individual will likely prefer they be sent to mental hospitals. I don't care, so long as there is a lock on the door.
Serial killers in general are perfectly aware of what they are doing, they just don't care about the judgement imposed by society on such actions and at the same time the personal payoff is too great to ignore.
What we should be concerned with is how we as a society handle mental health as a medical condition, not as a legal defense. I am talking about early detection, treatment, and if necessary preemptive detainment, not about how we handle the people we who have already gone Rambo.
From what I've heard, it doesn't seem like the shooter in this instance had things planned.
I don't know though, lots of questions.