We had two full time cops at my highschool. It was one of the best schools in the state, and in a really upscale suburban area. Didn't feel at all like a police state. I wouldn't put any faith in them to actually do anything in a situation like this though. They seemed pretty useless all in all.
At no time did any of my schools from elementary to high school have any sort of security measures whatsoever. None were ever needed.
This is the case for many, many schools around the nation. I'll grant that there are plenty of inner-city schools where such measures, and more... like metal detectors, regular drug sweeps, etc... are probably necessary.
Because those schools are attempting, half-heartedly, to teach the unteachable. Kids who have already given over their lives to thuggery and criminal behavior and who view knowledge and scholastic achievement as contemptible.
But for people to suggest that we need security measures across the nation at all schools, including the ones that really, honestly don't need any such thing? Because of some one in a billion thing like Sandy Hook?
It goes to show just how reactionary, fearful, irrational, emotional, and disconnected from reality a lot of people are. How utterly unable they are to factor in statistics and probabilities into their worldview.