Originally Posted by County Mike
Then again, the situation you're describing might be deterred if the shooter knows he faces the possibility of armed faculty. As it is, everyone knows you can walk into a school and expect to face zero armed resistance.
I 100% agree. Just the knowledge that they might come face to face with armed resistance inside of the school, would be enough of a deterrent to stop a large percentage of those targeted shootings. Not all of them, of course, but some of them.