Simply put, any school staff comfortable carrying a firearm should be permitted to carry a firearm. If some psycho wants to shoot up a school, they won't care about the "no guns allowed sign," but they'll probably be deterred, slowed, or stopped by someone else with a gun. People saying "let children learn peace!" are arguing something different. They should learn peace but "it's better to be a warrior in a garden than a gardener in a war."