As a society would like to believe that gun violence happens in spite of our best efforts, however our current laws have actually enabled recent mass shootings. The unintended consequences of the various Gun Free Zone laws have created venues for murderers. Schools are now optimized for people who want to kill as many as they can before they are stopped. Good people who might put a quick halt to these incidents are prevented from doing so by law. Criminals are not prevented from doing anything; they ignore the law. An immediate response from an armed citizen is is what violent criminals fear the most, and the possibility of such a response would cause many potential murderers to reconsider their plans.
Repeal all bans on concealed carry by law abiding citizens in and around schools.