You know, there's a different approach from the "policing the crazies" idea.
We could try not manufacturing a culture of emo-psycho anti-social dingbats for starters.
'Course, that would mean doing something with the schools. And that would mean changing the curriculum and methodologies.
Nah.
Let's just go get the guns. Well, that, and add three more layers of Nerf and bubble wrap to the process of exercising constitutionally guaranteed rights. And, while we're at it, maybe see if we can just do a blanket disqualification of some huge swathe of the population. Oh, and the Spanish Inquisition. Gotta have that. Nobody expects that.