It’s not a question of whether the robots could attack and kill people, it’s a question of whether they could defend the dictator’s interests. In a protracted guerrilla war against survivalist Americans with machine guns and large stashes of preserved food, not to mention access to tons of technology? I doubt it.

It’s not very difficult to attach a hand grenade (or even a pipe bomb) to a quadcopter drone and use it to attack a military checkpoint or a politician’s entourage. It’s simply much harder to defend than it is to attack nowadays, and centralized power is offset by scattered, decentralized resistance.

Finally, you might be able to convince a unit based in one state to attack another, but you’re unlikely to have the loyalty of all generals in a civil war.