For those who see the long-term endurance of the United States as a certainty, the idea that China could challenge US position in the current international order seems ill-conceived. There remains, many believe, an enormous gap between the United States and a rising China, which is developing fast but still lags far behind. Many strategic constraints that China will be living with in the foreseeable future reaffirm this conviction. Yet, while it may be true that China is in a weaker position than past rivals, the US must be cautious because it is also in a less favorable position than it used to be.