But, if the above isn't achieved, then what it will take are teachers also carrying, being trained in gun use, to quickly and effectively DOA any defective students who bring guns to school.
Exactly, John. It's what I've been recommending ever since I read about Professor Liviu Librescu holding the door in his Virginia Tech classroom while most of his students escaped through the windows. Seung-Hui Cho shot him through the door and killed him (along with 31 others, including one of his students who didn't make it out the window). As far as I'm concerned, every professor should be required to carry a gun and qualify on the range at least once a year. Any professor who refuses to do this should be summarily fired -- at least until colleges and universities cease being "gun free zones."
The idea that you can create a gun free zone is shot in the head by shootings like Hungerford, UK in 1987, Sollies-Pont & Cuers, France in 1995, Zug, Switzerland in 2001, and more recently Cardiff, UK in 2012, Alphen aan den Rijn, Netherlands in 2011 (according to Bart a gun free country), Liege, Belgium in 2011, etc., etc., etc.
If you think you can eliminate guns and shootings without arming the people who can put a stop to them you're whistling Dixie.