This is the deal: all American wars for the last century were, in principle, defensive ones. If China invaded its nieghbors, we COULD and WOULD bomb their armies a step past pergatory, because the US doesn’t want their land. On the other hand, China would never nuke South Korea, something that they DO want…
And a side note… I’ve studied about what China’s military was like in the late sixties… if the US HAD BEEN ALLOWED to win the Vietnam war, we could have sent 10 Divisions, (Which we DID have) fought north along the coastline, turned left, and NOT STOPPED UNTIL TURKMENISTAN. China coulda shoulda woulda been toast.