Key point: China would focus on ensuring North Korea survived and did not collapse.
Three years ago I outlined what the contours of a war between China and the United States might look like. Although disagreements between Washington and Beijing over Taiwan and the South China Sea have hardly subsided, it increasingly appears that affairs on the Korean Peninsula would provide the spark for conflict. If the tense situation in Korea led to war between the United States and China, how would the conflict start? Who would have the advantage? And how would it end?
How it Would Start
War between North Korea, or the DPRK, and America is more likely to ignite a war between China and the U.S. than vice versa, although it’s not incomprehensible that Pyongyang might take advantage of U.S. distraction with China to make a move against South Korea. But if we assume the former, it would change the military situation at the beginning of the U.S.-China conflict. Whereas in most scenarios a war happens according to Beijing’s timetable, and consequently to Beijing’s advantage, if North Korea triggers a conflict China may be forced into a fight that it does not want and is not fully prepared for. At the very least, it would allow U.S. forces to fully mobilize in expectation of fighting against China. Even if the Chinese were allowed to launch the first blow, U.S. forces would be on high alert, tracking Chinese moves and capable of responding immediately. The experience of November 1950, in which China was allowed to launch a surprise attack, would surely be at the top of the minds of U.S. commanders.