RS21311 -- U.S. Use of Preemptive Military Force
Updated April 11, 2003

	Background

During the summer and fall of 2002, the question of the possible use of "preemptive" military force by the United States to defend its security was raised byPresident Bush and members of his Administration, including possible use of such force against Iraq. It examines and comments on military actionstaken by the United States that could bereasonably interpreted as preemptive in nature. For purposes of this analysis a preemptive use of military force isconsidered to be the taking of military actionby the United States against another nation so as to prevent or mitigate a presumed military attack oruse of force by that nation against the United States. Thedeployment of U.S. military forces in support of U.S. foreign policy, without their engaging in combat, is not deemed to be a preemptive use of military force. U.S. military forces were permanently withdrawn from Nicaragua in 1933. (10)
Iraq War of 2003.
This report reviews the historical record regarding the uses of U.S. military force ina "preemptive" manner, anissue that emerged during public debates prior to the use of U.S. military force against Iraq in 2003. It examinesand comments on military actions taken by theUnited States that could be reasonably interpreted as preemptive in nature. For purposes of this analysis apreemptive use of military force is considered to bethe taking of military action by the United States against another nation so as to prevent or mitigate a presumedimminent military attack or use of force by thatnation against the United States. The deployment of U.S. military forces in support of U.S. foreign policy, withouttheir engaging in combat, is not deemed tobe a preemptive use of military force. This review includes all noteworthy uses of military force by the UnitedStates since the establishment of the Republic. A listing of such instances can be found in CRS Report RL32170, Instances of Use of United States ArmedForces Abroad, 1798-2003. For an analysis ofinternational law and preemptive force see CRS Report RS21314, International Law and the Preemptive Useof Force Against Iraq. This report will be updatedif significant events warrant.