The more interesting scenario to consider, IMHO, is a civil war between a controlling but “not the US” majority, and a resisting minority. For example: what would happen if there were a modern Red Scare, but one with a basis in reality—i.e., if somehow >50% of the US (including our political leaders) were subverted by China, became believers not just in Communism but in the CCP’s propaganda about Communism necessitating political unification and erasure of separate cultural identity, and so the belief that the US should volunteer to be annexed+absorbed by China?

If the majority of the US believed that... what should the rest of us do, at that point, to stop this from happening? Is the correct answer just “the US is a democratic nation, so if the majority of the population wants the US to stop being a democracy, that’s the ‘democratic choice’, and if you believe in the ‘power of democracy’, you should support it”?