I have always said that bans do little to stop violence. I think that there are cultural issues in the U.S that cause our mass killing problem. I say this because there are other countries that have high rates of gun ownership but very low rates of violent crime. If guns were the cause we would expect to see countries with more guns have more violence but the facts don't bare that out.
Guns are a political issue because they get people all fired up to vote for whomever they agree with on the topic and nothing more.
I wrote a piece on the shooting on my page that covers my thoughts on school violence in more detail than I can provide here.