Locally, there have been School Resource Officers at the high schools for several years, but not at the lower schools.
I think they were there mainly to deal with students, not outside threats. Maybe recent events will change things.
Our County has SROs (Sheriff’s Deputy) in all the public schools during schools hours.
That strikes me as a very good idea. Many small towns have relatively small pollce forces and compensation for those officers already amounts to a good part of the budget for such towns. Having an assistant principal, or similar school officer, with a CCW permit who’s also been trained to respond to a potential shooter situation, would provide the necessary protection at a far lower cost.