Pax,
You might wish to read up on China-Vietnam history.
China invaded Vietnam quite a few times over the years.
Somewhat recent history beginning in 1945 will show the two nations have had wars, invasions, and occupations.
As to the current situation in the USA....not much to argue as lots of problems extant.
China will use economic "war" rather than engage in a "military" war if they are as wise as they have been down through the ages.