I'm not saying it should be the norm and I agree once is more than enough but I'm being realistic. If someone truly wants to shoot up a school, its going to happen, that is pretty evident. I never said it was never going to happen, I said the chance of it happening at a school is very very low, that's not to say that it won't. Because of this, the school board isn't going to add security guards to their ever shrinking budget and armed teachers is not a good idea. How does it get prevented? More screening, more tightening on gun laws. Banning automatic weapons? With how America thinks right now, that's never going to happen and even if it did, I'm sure his mother would've had a semi-auto for him to steal instead. Every single mass shooting case I've ever read about, I've seen that it could've have been preventable if the people in the perpetrators life had watched a little bit more closely. 9/10 there were signs way before this happened, yet no one does anything until it is too late. That's the problem.