Not a bad idea. About $400/student - 3% to 4% of total spend. Everyone on board for raising taxes to make them available? If not then where to get the money from?
Uh, at Sandy Hook that would be $280,000/yr. I think they can find a part-time armed guard for less than that.
In my local school district that would be $600,000 a year for a district with 1500 students and 3 school buildings. There are 43 teacher aides on the payroll. Cut a couple from each building and you can pay for a guard.
I call on schools in my line of business. Many have a security desk in the front manned by what looks like retired citizens looking for some extra cash. Their responsibility is to make sure you sign in when visiting the school - great security measure.
Why not man the security desk with a real armed security guard? The only thing lacking is the will of the government run schools to do it.
If the teachers were allowed to carry, there would be little cost. They should be professionally trained but there are numerous places where they can get good training.
Also, many towns have volunteer fire departments. The costs are minimal. How about the same setup with a couple of on site armed volunteers (properly trained and deputized, of course). Perhaps there should be an off duty or retired (or even an active) policeman in charge? That would give some defense in depth. The school could provide the radios and lunch and the volunteers would provide their own (approved) weaponry and time.
This isn't rocket science, but there are a lot of laws, lawyers, and politicians in the way.