The Bush administration has shifted from the six-decade US national security strategy of containment to one based on what is called forward deterrence. Consequently, the president now claims for the United States ‘the prerogative of using force preemptively and unilaterally, however its interests dictate’. This represents the most sweeping reformulation of US strategy in over half a century. The result, however, will only erode America's reputation and squander its ability to exercise leadership on pressing global issues.