I don't think banning guns and rewriting the consty is going to solve all America's problems. Essentially what caused this was psychological problems, economic hardship; and the failure of the system to stop crazies from getting their hands on guns and shooting up the community. Columbine and now the Colorado shooting show that the system has consistently failed to prevent (and report) problem students before they go wild and endanger the lives of others. Rather than raging at guns, they should be looking at their own communities; why didn't the University do the decent thing and tell the family and the community about this guy, before he shot up the neighborhood?
It would be illegal to do that. It would be a violation of the crazies civil rights.