As this has been argued, my thoughts have changed on the subject. I previously thought that it would be good for a teacher to get CLEET certified, etc., but I think I was missing the point. My wife is an educator and I really think the recent school shooting clouded my judgement thinking teachers should be there to protect children. I don't think teachers should be armed security for the school, I think they should be armed to protect themselves, just as I have the right to do so.
If somebody breaks into my wife's classroom, she should be able to protect herself. It's a benefit that the children in her classroom are protected by circumstance. I don't want my wife actively hunting down a shooter on school grounds. Don't go looking for trouble, but if trouble finds you, be prepared.
My wife is a teacher, and this is exactly how I feel.