It really depends on what would be happening in the military and intelligence services.

I don't think people really understand just how much a civil conflict would be a war of information as opposed to a war of arms.

If things got bad enough domestically that laws like the Patriot Act were expanded and agencies that haven't been supposed to operate domestically suddenly could, and those agencies were still 100% under government control, you'd have vans (or simply drones) taking out domestic terrorists in the middle of the night right before the day they were supposed to organize to kill and terrorize their neighbors.

The US could become an almost unthinkable police state under the control of a government like China's or if we had a Stalin-esque administration.

This is the part that Y'all Queda don't fully grasp. They aren't hiding out in caves in Afghanistan or air gapped in Pakistan. The only thing keeping them safe from the monsters under their bed that they largely don't realize are there is the very government they think would be such a bright idea to try to overthrow. And if that government saw them as enough of an existential threat to unleash the monsters on them, well, they'd have quickly succeeded in overthrowing the US government in a sense, but wouldn't be around to see it.