One of the main problems for the U.S. in a war of any duration with China is that we will be riddled with Chinese spies and potential terrorists. It is impossible in both a political and a practical sense to expel the Chinese born from our industry and research labs. So China will have a built in reserve of overseas Chinese, with an inevitable percentage that will see their loyalties with China and not the U.S. Whereas China will have no problem expelling westerners from its sensitive installations. Would a new Manhattan project be capable of protecting secrets from China in the age of multiculturalism and instant electronic communication? Not very likely.