Should China really wish to take our ground, they will have a fight on their hands.
China would formidable opponent for a war fought near China. China does not have the power projection capabilities to be a significant threat to mainland US in a conventional war.
How many Chinese are in our country now? Where do their loyalties lie?
5ish million. I would say the loyalties vary widely, however I'm no more worried about the loyalties of Chinese immigrants than I was worried about the loyalties of the 3 million muslim's that we had in the US while we were fighting the war on terror, and the potential for radical loyalty was far higher for the latter than the former. Could there be some terror attacks in the US from Chinese loyalty to the motherland? Yes. Are they going to bring America to its knees? No, and it won't even require a thought of bring back the draft to address.