This needs to be re-stated: What are you calling an "Assault Weapon"? The federal Assault Weapon ban pertained to cosmetic features only, not the rate of fire. If the firearm could only fire one round, with each pull of the trigger, but possessed a cosmetic feature (pistol grip adjustable stock, etc) then it was illegal as an "Assault Weapon". This ban had nothing to do with automatic weapons. Both the CDC and the United States DOJ published reports after the Assault Weapons ban stating that it had little to no effect on violent crime.

The problem is, the media sensationalizes guns, and what you think of when someone says "Assault Weapon", is actually a military grade "Assault Rifle", which is very different. An Assault Rifle is a firearm that can fire multiple rounds with one pull of the trigger. Semi-automatic firearms can not do this, and they can not be changed to do this without expensive modification, by a highly skilled machinist that is licensed to do so. Just to be clear, Assault Rifle's are very regulated by the ATF, are very expensive, and have a long (months) process required in order to get one.

Not to stir the pot too much, but all of these shootings are happening at schools, which are Federally mandated "Gun Free Safety Zones". These nut jobs know that no one there can defend themselves. I'm not saying everyone should have a gun. I am saying that when the bad guys can't tell who has one and who doesn't, they are going to be a lot less likely to do regrettable things