In this sixth year of the 21st century, one might argue that the American unipolar moment has ended, or that unipolarity has been revealed to be not at all identical with omnipotence. In either case, many Americans now feel less safe than they did ten years ago. The anxiety has many sources, all of them with an international component. There are the continuing wars in Central Asia and the Middle East, the ever more alarming terrorist threats, the relative decline of US manufacturing, the uncontrollable fluctuations in petroleum prices, the demographic transformation arising from Latin American immigration; and, an as...