> To even get to this point you would have to assume that the US would devolve into a civil war, in which you can also safely assume that many in the US military would be defectors (leaving a lot of empty tanks and airplanes, if not turned to the "other" side).

I hear this a lot from the right, and I think it's hogwash. The Biden administration has already begun ideological screening of military personnel. If the government is forced to go to war against its own people, it will be mostly aging, out-of-shape fanatics on one side and highly-trained, highly-motivated, younger loyalists to the legitimate government on the other. It'll be a rout.