I, too, thought the idea of police in the schools was a bad idea back when Bill Clinton signed off on federal money to make it happen (http://articles.latimes.com/2000/apr/16/news/mn-20323).
However, this must have made some contribution to reducing gun deaths among school children over the years.
Now that the NRA endorses the idea I’m all for it.
I’m not sure, at the least, a full cop is NEEDED. Private guards, some of which are unrevealed second careers of teachers, should suffice.