In Environment, Power, and Society, Howard Odum wrote something to the effect that systems are limited in what they can do by what the larger systems of which they are parts will allow, and by what their own subsystems can provide for.
Thinking about gun violence, particularly inane mass shootings, in terms of systems, can be frustrating because the system is much larger and more detailed than individual, weapon, and victims. Where do you draw the line?
Adam Lanza, the reported Sandy Hook killer, was an un-photogenic twenty-year old Aspergers sufferer, with another learning disability, and divorced, affluent parents. That's somebody who had to have been part of a bullying system, who didn't have the internal system that would let him understand, cope, or avoid. He may have been alienated from his parents, or they from him. "Who knows what's going on in the kid's head. I don't know what to do with him. Listen, the child support's late again. When are you going to realize that you have a responsibility here too."
And yet, there are a million kids that fit that description.