I remember quite some time ago, that while the US is so involved in their own civil war, the Chinese will invade and attack.
It was eons ago and have no idea where I read it. Seemed far fetched back then....not so much now.
You have any idea of the sealift capacity needed to move an invasion army of sufficient size to conquer a continent? The US and Britain were challenged to put one together for D-Day, and that was from a secure base only a few miles from the target. The Chinese would have to cross thousands of miles of open water.
While it is theoretically possible US ground forces could be tied up in a civil war, the US Navy is more or less by definition unable to participate effectively in such a war, and might have something to say about whether a Chinese invasion fleet could make it here.