i think a war like this would result in hundreds of millions of people dieing, maybe even billions. USA has the better technology but china is catching up fast. The one thing going in USA's favor is its allies. Im pretty sure all of the european union would join in as well as canada, australia japan and India. Im not sure about Russia though, they might join up with China. North Korea would also be on China's side as well as Iran. In the end USA would win but I wouldn't be suprised if half of the country was wiped out. Not to mention the huge cost of a war like that.