At The National Interest Harry White considers the circumstances would lead us to go to war with China:
The administration has hoped that Beijing will think that everything in Asia is important to America—from overlapping maritime claims with Vietnam to Japanese sovereignty. But from Beijing, it looks possible that nothing in Asia is that important to America, or at least not important enough to go to war with China over. Whether that’s accurate or not, it’s a thought that is slowly creeping into the minds of some of America’s allies too—and it has them worried.
There is a danger that this thinking at cross-purposes could precipitate a crisis, and that crisis could turn into a war. China might cross an actual American redline, which ironically, the White House won’t have articulated clearly enough to avoid antagonizing Beijing.
I strongly suspect that the Chinese believe that there are no circumstances under which we’d go to war with them. That is, perhaps, the most dangerous situation imaginable. Have a nice day!