A ground invasion is out of the question for the Chinese. There are too many armed civilians in the United States for any nation to occupy it. Lulled into complacency, an enemy soldier could assume another civilian is strolling by, only to be ambushed by an armed citizen ready to give their life for their country.
The geography of the United States is also ideal for defense, the mountains in the West and the rugged hills in the East would make a breakthrough to the heartland extremely difficult, not to mention bloody. The variance in terrain and large urban centers no invading force could easily bypass would give the Chinese a lot of trouble.
FLASH POLL: Should Adam Schiff RESIGN?