What's an armed teacher going to do upon the event armed and trained professionals suddenly appear upon the armed teacher, armed teacher has a gun, and panics from the sight of the SWAT team with much bigger guns pointed straight at the armed teacher? Are we wanting to expect our teachers now to put their lives in peril if they get scared? And lets be realistic, it will do nothing to prevent school shootings, fail to address why we have them, and working to maybe prevent a few more deaths and injuries at best. And the shooters may potentially learn who is carrying, and could plan accordingly. And don't forget these are teachers facing a day they never thought would happen to them going to hunt down someone who made the decision to kill some time ago. The outcome is not favorable for the potential would be "good guy with a gun." That won't be the case in all shootings, and some will by happenstance be trained or have faced favorable circumstances in such closed in spaces, but school isn't shoot-em up flick. At best, arming teachers will save a few lives. It's a tiny-dot band-aid for deep and wide wound that requires stitches.