We can be absolutely sure that within a few years more people would be killed by teachers who fired their weapons accidentally or in misplaced anger or fear, or by students who stole their teachers’ guns, than have ever been killed in school massacres like those in Newtown and Columbine.
But what troubles me most about this suggestion — and the general More Guns approach to social ills — is the absolute abandonment of civil society it represents. It gives up on the rule of law in favor of a Hobbesian "war of every man against every man" in which we no longer have genuine neighbors, only potential enemies. You may trust your neighbor for now — but you have high-powered recourse if he ever acts wrongly. Whatever lack of open violence may be procured by this method is not peace or civil order, but rather a standoff, a Cold War maintained by the threat of mutually assured destruction.