That's fine as a last line of defense. I'd prefer the treained professional; to squelch the situation up front.
I would not deny anyone their second ammendment rights. I just don't see teachers as a first line of defense. I'd prefer a trained, professional to get the job done right and quick. No thought...no emotion...no hesitation...Identify the threat and eliminate said threat....bang done. Go have lunch and the kids can get back to learning if they've even been interupted.
The trained professionals waited outside while Cho killed the students at VT.
We hear more and more stories about trained professionals such as SWAT teams being used and they break into the wrong house and kill innocent people themselves.
The best person to protect ones self is ones self. As the saying goes when every second counts police are only minutes away.
As I said before infringements only benefit the criminal because they create an imbalance of power.