Lil devils x said:
Some schools have dealt with this by arming their staff.
http://www.telegraph.co.uk/news/worldnews/northamerica/usa/2575524/Texas-school-allows-teachers-to-carry-guns-into-class.html
It will be an interesting proof of concept in Texas though as it is I don't think it is replicable throughout America and especially not the rest of the world.
Texas has a very well established firearms culture meaning there is a high likelihood that someone in the teach profession is not only willing to carry a firearm but is also competent enough to use it.
I think it is a necessity that the local law enforcement is deployed to schools but in a VERY PARTICULAR capacity of primarily Perimeter defence: they man the metal detectors and patrol the perimeter fence and even road blocks to defend against "ram raids". In other words, treat schools with the same security precautions as airports.
Airports used to have very little security, but throughout the 60's and 70's after a serious of terrorist attacks law enforcement finally cottoned on an realised what a sensitive target it was and how tempting it was to those with homicidal intentions. Airports were one of the first true "gun free zones" but back in the good-ole'-days it's wasn't a political gimmick it was for real.
The same lesson must be learnt from shootings and other education establishments as these ARE "soft targets"
CAVEAT
It is very important that schools allow to continue to function as schools, the police must be there to prevent outside attack or smuggling weapons for internal attacks but the general enforcement of the school rules must remain with the teachers.
Cops are trained and experienced to detaining crack-heads, jail-birds and drunken adults... not immature children. Teachers are far better at breaking up 13 year olds having a slap fight than some cop hardened by the street. Trouble - including criminal behaviour - must be dealt with in the principal's office before being sent to the police interrogation room.
A good principal knows how to deal with a kid who vandalises property, what is the best balance, but a cop will only see a law broken and a crime to be prosecuted.