Comment by AngryData

If they arm and empower a significant local population, they do have a credible defense, because the vast majority of leaders in the world knows fighting a decently armed insurgency is extremely costly. They watched the US itself, a military that dwarfs the entire rest of the world's militaries, do it multiple times, along with Russia and a few other countries. The "cheapest" way to win against an insurgency is to literally blow the entire country up until nothing is standing à la North Korea, but that also destroys 95% of the value of taking a country which defeats the entire point of taking it.