If OP isn’t American, school shootings probably aren’t something to even consider… My thoughts go towards being treated poorly by educators more than anything. Bullying from other kids can suck, but in my anecdotal experience (outside the US) the lasting and impactful traumas stem from how teachers and staff deal with the kids.
Um… Let’s take a quick look at the American military’s track record real quick… They tend to lose when fighting a decentralized, insurgent force (VC, Taliban) which is exactly what the citizenry of the US would turn into if the government turned on the population. Not to mention, a ton of military personnel would hold the same values of said insurgency, meaning that, at best, some would think twice before attacking, and at worst they’ll defect, bringing millions worth of fancy kit to the other side. I don’t have a dog in this race (not American) but I think it’s ridiculous to underestimate the capabilities of an angry populace.