Originally Posted by Rochard

Maybe... But that is only a part of the problem. Just because you have a single armed guard doesn't mean he (she) will be able to stop a shooter. In the Columbine, officers showed up at the scene and the killings kept on going.

And this only protects schools - not shopping malls or movies. Or churches.

Then... By the time you require an armed guard to take out a shooter, it's already too late. The damage will have been done. This is like saying "The best way to handle drunk drivers to run them over after they have killed someone".