|The answer to the gun problem—more guns.|
There are some very practical reasons that arming teachers is not a tenable or viable solution, and none of them have to do with gun control or my personal position on the matter. Let’s just touch on three:
Economics—According to the National Center for Education Statistics, there are currently "3.2 million full-time-equivalent (FTE) teachers". A new Glock 9mm runs between $450 and $550 (depending). Assuming Federal government lowest bidder and bulk buy at $300, that's a $960,000,000 price tag (yep, almost a billion dollars in initial expenses). This does not include the cost for "standard" training (whatever that would be), certification and re-certification, or coaches (I'm a walk-on coach and gun owner), part-time and substitute teachers.
Moral/Ethical/Religious—The base assumptions is that teachers unions and school districts would just go along with this. They wouldn't, BUT requiring teachers to become efficient with firearms will definitely go against a high percentage of teachers' moral, ethical, and/or religious considerations. The Selective Services Acts and the Supreme Court have already made it clear that no one can be forced to carry weapons in the service of their country.
Practicality—There are already guns on campuses. The federal Gun-Free School Zones Act doesn't apply to anyone who is licensed by the state/county/city of the Federal government to carry a firearm—such as police who patrol campuses, or CCW permit holders. In most mass shooting cases, there has been a firearm near or present. In most of those cases, the "good guy with a gun" scenario did not play out for any number of reasons.
None of this discusses the additional risk or putting a firearm in every classroom on every campus. The increased likelihood of accidental shootings, or of students doing something incredibly stupid. In the case of active shooter incidents, there's as much a chance for teachers to shoot the wrong person, or to be shot themselves as law enforcement moves in to secure the area.
The number of issues and scenarios where things can go wrong VASTLY outweighs any even slight increase in potential safety.