A lot of it comes down to institutional strength. There's probably some good academic models for this, but I'd say: 1) Institutional cohesion and alignment wit

A lot of it comes down to institutional strength. There's probably some good academic models for this, but I'd say: 1) Institutional cohesion and alignment with population. Many dictators have ethnically homogenous security services - their clan, tribe, whatever. People are loyal to the ethnicity, not the country or institution. That's how you get a nations military killing it's own people. In democratic western countries, the military is much more reflective of the overall population, which puts a check on that. 2) Training. Just because Syria has "jets" doesn't mean they're well-maintained, flown by skilled pilots and employed with excellent tactics. It's very expensive and time consuming to apply the tools of modern war. NATO nations spend a ton of money training their troops to improve effectiveness. Really, I think the first one is most important. Theoretically you don't get violent uprisings in western nations because democratic governments are more responsive to needs and social composition of the population.