Can this thread not be turned into a "this would not have happened if..." circle jerk? Please?
And that goes beyond just gun laws, that goes for anything else someone wants to propose as an arm chair security expert, just like the whole "movie theaters should have metal detectors" line after Aurora, or anything relating to better psychiatric care. Just shut up for a minute and admit it: you don't know.
I don't have an answer for this. I think it's fucking sad that there aren't places that can be taken for granted as safe, especially for young children. And it's likewise fucking sad that save from turning every school, mall, and public place in America into a fortress, which is not functionally possible anyway, there is no way to ever be sure this would be the last time, as much as everyone wants it to be the last time.