So here is an article about a lawmaker in Wisconsin who wants to introduce legistation that would allow teachers to carry concealed weapons in shool, citing how this seems to work for schools in Thailand.
Thailand. "Where officials have been waging a bloody fight with Muslim separatists for the last two years..."
Now let's think about what just happened in the Amish schoolhouse in PA this week (forgetting for a moment that it's an Amish schoolhouse, and the Amish wouldn't carry a gun anyway). So the teacher owns a gun. Probably keeps it in her desk drawer, because you can't conceal it under a skirt too well. A gunman bursts in. The teacher is at the blackboard. The gun is twenty feet away in a desk drawer. Seems pretty pointless, and chances are good the teacher is gonna get shot in the process of diving for it.
And I think about that teacher in high school that tossed an eraser at my nose when I gave a dumb answer (I deserved it, and never once thought about a law suit) and wonder just how many unstable teachers there are that really shouldn't be toting guns in the first place.