Our very large (3,000 kids) high school campus set in an affluent suburb started to have problems with drugs (the school was originally supposed to house 1k kids, has been growing like crazy over the past decade), so the county built a police station right next to the campus. Unsurprisingly, things have improved.
We think nothing of constantly seeing armed cops, cop cars, and drug dogs wandering around campus-the kids have a good relationship with the police, have no issues with the presence of the police there (a lot of the cops have kids going to that school), and there’s a pretty amazing facebook page that keeps everyone informed about what’s going on on a day to day basis (maintained by the police).
The police did a practice terrorist attack on the school one day earlier in the year and kids were allowed to participate. I didn’t let the girls do it because, having been in a traumatic situation when I was a teenager (not terrorist related, but a catastrophic train accident), I knew they would be deeply affected by it, even though it was a “faux” attack. The practice run led to some good changes in how the school allows people on campus, and most agreed it was a good learning experience from all involved.
But my point here is that having armed police on campus can be a good thing if the relationship between the police, the campus administration, and the students is open, supportive, and transparent. They need to be all on the same side.