Im sure China would be very careful about participation in war involving USA (they are to smart for that and like their money to much).
When we fought for S. Korea way back it was one horrible war that's seldom talked about today (Im not sure where I stand on South or North Korea anymore
We gave so much and did so much to enable S. Korea to become who they are today and I'm just not sure they really think of themselves as friends to us
I see thanks, respect, honor and integrity, mercy, kindness from Vietnamese, Chinese, Japanese etc. (maybe I just haven't befriended enough Koreans yet, idk... I just hope if we send our boys in their to rescue them again that I feel a little more like an ally to their people and not an enemy).