This is all wild speculation on our part, as AFAIK, there hasn't been any direct attacks between two nations that have nuclear bombs except some skirmishes here or there (and being able to do that doesn't warrant an extra $24B spending). At most, war by satellite (USA supports country A, Russia supports country B, and A and B bomb each other). Maybe I'm being unimaginative, but I can't see how direct attacks between China and US wouldn't escalate to a nuclear war, even just due to egos.