When and under what circumstances should a nation strike first? In the months following the terrorist attacks of Septmenber 11, 2001, President Bush and other U.S. leaders announced that, in the future and under some circumstances, the United States would strike enemies before they attack. In particular, the National Security Strategy declared that preemptive attacks would be an important tool of American policy to deal with threats from terrorists or from rogue states armed with weapons of mass destruction. This volume explores the implications of the doctrine of preemption for U.S. strategists and military planners.

The authors examine the range of anticipatory attacks, including the differences between preemptive and preventive attacks; the costs, benefits, and risks associated with striking first; considerations of legality and legitimacy that must be weighed before striking first; and the prospects and implications of preemptive and preventive attacks in future U.S. national security policy.

After discussing the leading scenarios for U.s. anticipatory attacks and studying past cases in which the United States or other nations ahve considered striking first, the authors conclude that preparing for such operations should not be a key driver for change in U.S. military capabilities. Large-scale U.S. first strikes will be infrequent and present few unique operational military requirements, according to the authors, although the intelligence requirements for these strategies are highly demanding. Policymakers and military planners should also recognize that this doctrine may have unintended results, including potentially making preemptive attacks attractive to U.S. adversaries - states or other actors expecting to be attacked by the Unites States may themselves perceive powerful incentives to strike first.