After Inchon, MacArthur predicted we'd be home by Christmas. Then the human wave of Chinese "volunteers" crossed the borders. We finally signed an armistace (cease fire) in 1953, only after Eisenhower threatened to use the "nuclear cannon".
China could tie in knots just by calling in our debt; armies run on money. If that were not bad enough, Russia is likely to get into this fray, first using Iranians are surrogates, just as I have been predicting on these pages for the last several weeks. '
BTW, Great Britain beat China because of its superior artillery and the corruption of the Chinese Dynasty. China is on the move technically and has relatively new heavy industry. Underestimating them could be a fatal mistake.