I fully anticipate this thread to be locked, because rules (which is of course fine and civil) but here's my $.02 since everyone is talking guns in schools:
I work in a large public high school, almost 2,000 students. The state police held a live shooter training for faculty in which we were chased and shot at by someone with an AR15. Very loud, very disorienting in the cement hallways. The point was to actually simulate what you'd do when someone fired at you - they wanted to intentionally panic us, and frankly it was actually terrifying, no matter how tough I may be while watching Die Hard, pantsless, on the couch at home.
We all learned a lot about ourselves and each other - to put it quite mildly. One lesson, directly from the troopers' mouths was that in the event of a real shooting, there's no way to guarantee that anyone or everyone will be safe. This lesson was delivered after the "shooter" appeared by surprise in the room where we were, and we had (as a group) to attack him physically (he was wearing a padded suit). As it turns out, I'm real quick to flip a table over on someone. I did not know this about myself.
At any rate, having one person shooting was insanely confusing and scary, even if you could actually see that person and know it was a drill. They made us practice exiting the building (having booby trapped it and blocked doors and such) with the shooter chasing us, and that was actually terrifying. I died in the drill because I ran past a pipe bomb that I didn't see, because who anticipates bombs near the water fountain?
Even with all that, I would certainly do the training again and again - no hesitation, but I would not carry in a school, and I think that the idea is not sound. Sure, on paper, it makes sense to have a small army at all times, but the shooting happens over the space of seconds, and it takes nearly five minutes to walk from one side of my building to the other. By the time anyone even sees a text message or picks up a radio, it's all over. And with over 2,000 people in the building, in a real shooter situation it is actually impossible to be able to accurately understand where the shooters are, who they are, how many of them there are, and so on. Add to the mix six or ten regular Joe Plainclothes teachers who are also strapped, and you have a recipe for total pandemonium - crossfire - mixed signals - and certainly more deaths.
Lockdown drills are absurd, but so is a school shooting, so we do them. However, in a real lockdown, the entire school becomes compartmentalized behind 2" oak doors with zero visibility inside cinder block walls. A shelter-in-place is a good safety plan, and we drill it. As shitty as the whole thing is, a lockdown and subsequent SWAT team entry would, in my opinion, having observed and run the drills in my own building, result in fewer (not none) casualties. There is no zero casualty situation.
This next part is pure hippie, so take it or leave it, but I work with teens every day and leading by example is the most important value I have. This hypothetical situation, of course, leaves aside the social and political problems of arming teachers. There is no such thing as an equal conversation when you speak with an armed person, and you cannot expect teens to mature and learn to respect adults (and become them) when there is *always* the threat of deadly violence, because the staff is armed and the students are not. School shootings are comparatively rare enough that I will take my chances. The odds of dying in traffic are vastly higher. However, every single day I and my colleagues are faced with aggressive, stupid, and cocksure teens who challenge authority and attempt to tear down The Man (ie. me). I am a very patient person, but everyone has their breaking point, and I am tested on a daily basis, which is stressful enough without having the ability to kill someone on my belt at all times. Balancing that situation with the possibility of deadly force turns the school into a de-facto prison, where I, the gun, am the guard, and the students are inmates, whether we intend / acknowledge it or not. I'm not afraid enough of school shooters to do that to myself or my kids.
Please note, before y'all flame me to death, that I'm not registering any kind of opinion whatsoever on carrying in public, owning personal firearms, or any such thing. I'm not affiliated with a political party, I donate money to zero special interests, and I happen to own some firearms of my own (but do not carry in public). I'm just trying to give some context to the possibility of armed schools. If anyone wants to talk about it, I'm happy to PM, but I sincerely don't want there to be a flame war, and I'm not denigrating anyone else's stated positions here.