U.S school spending has almost always gone up and gone up a lot. So not having a budget to afford pencils, is a fairly bullshit analogy.

And while I think arming every single teacher is an unreasonable request, having armed security is perfectly legitimate. While being a band-aid to solve another possible problem, that along with having metal detectors. Might just be the smartest and most effective way to deal with this issue. 

Nearly all mass shootings are taken place in gun-free zones. We have a consistent pattern and that's a solution that's actually constitutional.