I think it's more likely the China reds fund one side (as they're already doing) and the other side gets funding from presumably the West, maybe Russia takes the opportunity to hit China as well and funds the opposition while fighting China on the eastern front. In any case it won't be an open invasion. How the fuck they going to invade? They don't have the ships to transport all the troops it would take. Though they could probably set up a stronghold in Commiefornia; I'm sure Hawaii would suck red dick pretty quickly too. It'd be a mess.