While I'm sure there are a few, plenty, some....teachers out there that could/would handle themselves just fine with a handgun/weapon on school grounds, I personally believe that our liberal school system is failing our society by making everybody special, a winner, perfect....etc etc. I personally believe that 72.34% of the teachers in the country would be aghast at carrying weapons.
Which is why I think D-20 in Colorado Springs has the right formula of armed security personnel in the schools (which from what I have heard, most are retired LEO, military or aspiring LEO looking to gain some experience while trying to apply). To also include armed patrols in cars that can respond to different schools as an on needed basis. Most vocal parents I have heard are happy to have this security in place....usually right up until their snot nose kid gets busted for smoking pot on school grounds.

Note: 84.57% of statistics are made up on the spot.