One thing jumps out from the mental state article is that this guy never had an incident where he broke the law because of his mental illness. If you’re convinced that you’re sane, even thought you’ve lost the thread, the most likely way you’re going to get into the system is by hurting yourself or others. Until a week ago, this guy hadn’t done that.
Arizona makes it much easier than many other states to force a mentally disturbed person to get psychiatric help, even without evidence of dangerous behavior.
A provision in state law, little known outside the law enforcement and mental-health systems, gives any adult the right to petition the court for a psychiatric evaluation and, if needed, court-ordered care for someone “persistently and acutely disabled” by symptoms of mental illness but unwilling to seek or follow medical advice.
This provision wasn’t used by Pima College after they threw the guy out for creating that obviously insane video John mentioned.
Mental health care is woefully underfunded, but it wasn’t just lack of money that caused the shooter to drill into his insanity without getting any help. Preventing another shooting like this one is going to take a combination of laws and institutions willing to petition under those laws, and there’s always the danger that simply unpleasant behavior will be punished by overzealous or overcautious bureaucracies at colleges and universities.