Double edged sword. People who commit these massacres and a majority of criminals have sever mental health and or drug issues. They shouldn't have access to firearms. But, new laws may prevent people from getting help because thy are afford of loosing their guns.
"If someone has a gun and is trying to kill you, it would be reasonable to shoot back with your own gun.” - Dalai Lama (Seattle Times, 05-15-2001).