For myself, I think the second amendment is the problem. You don't solve the killing issue by getting rid of assault weapons. Hand guns are also a problem.
The issue is far larger than the way it is presented.
Would you be willing to lose the right to bear arms to bring back the lives of those twenty children? Because that is the way to save their lives from armed killers.
It isn't going to happen. People don't want to pay that price. So the problems will continue.
The will to change the culture just isn't there. The critter hunting desire is stronger than the desire to protect children.