Schools, large high schools in particular, have succumbed to the societal notion that beyond certain areas that are the domain of authority figures, everywhere else is an authority-free zone. It has turned schools into replicas of public streets and meeting places. Adults have only marginal control of non-classroom and administrative school space. It is no coincidence that the killers attacked most successfully in the cafeteria, library and hallways where adult supervision is weakest. Many shopping malls now have more rules of behavior that high schools.
School administrators are under siege.
If they try to reassert traditional authority, they come under fire from the individual rights bar. If they don't, they are accused of dereliction of duty. In self-defense they have stepped out of the loop, deciding to shrug off much of what they feel they can no longer control. They have, in effect, retreated to their bunkers. It's time for them to stiffen their backs and come out fighting.