>in iraq, the insurgency was the former iraqi military, not just random citizens with small arms

We are quite far from a situation of mass repression of citizens in the United States like you see in Iran. But if it came to that, I imagine the 15 million+ veterans in this country might have something to say about it. They outnumber active duty military personnel by a factor of 5.

And even Iran had to pull in outsiders because their military wasn't willing to fire on their own people.