Jon Chait observes that “For a revolution to succeed, it generally needs one of two things to happen: Either it needs its own weapons, or it needs mass defections by the state security forces.” He also sees some evidence that some elements of the security forces may be contemplating defection.
I think it’s worth emphasizing that in the modern world at least, the balance is tipped pretty overwhelmingly to security service defection rather than actual armed overthrow of the powers that be. The reality is that modern military technology makes it extraordinarily difficult to actually defeat a state on the battlefield. An dissident movement just isn’t going to be able to be able to blow up tanks and airplanes. Under the circumstances, strategic nonviolence is a vital tactic. If you were to try to fight the security forces—shoot some policemen, say—you’d encourage a more serious crackdown. It’s through nonviolent resistance that you heighten the psychological contradictions, and encourage the regime and its enforcers to blink. From the Velvet Revolution to Tiananmen Square to the Orange Revolution to what’s happening today in Iran, the brave dissidents are essentially daring the security forces to beat or kill them. The bet is that when push comes to shove, people in the Iranian security forces have some humane and patriotic instincts and will recoil from the idea of using mass violence against their fellow citizens. And it’s a terrifying bet. We’ve seen time and again that it’s a bet that often pays off, but as we learned in China 20 years ago there are no guarantees.