U.S. Preemptive Military Force



By Richard F. Grimmett
National Defense Specialist
Foreign Affairs, Defense, and Trade Division
U.S. Congressional Research Service

This report reviews the historical record regarding the uses of U.S. military force in a "preemptive" manner, an issue that has emerged from the recently released U.S. National Security Strategy of the United States. It examines and comments on military actions taken by the United States that could be reasonably interpreted as "preemptive" in nature, says Richard F. Grimmett, a specialist in the National Defense at the Congressional Research Service.


In recent months the question of the possible use of "preemptive" military force by the United States to defend its security has been raised by President Bush and members of his administration, including possible use of such force against Iraq1 This analysis reviews the historical record regarding the uses of U.S. military force in a "preemptive" manner. It examines and comments on military actions taken by the United States that could be reasonably interpreted as "preemptive" in nature. For purposes of this analysis we consider a "preemptive" use of military force to be the taking of military action by the United States against another nation so as to prevent or mitigate a presumed military attack or use of force by that nation against the United States. The discussion below is based upon our review of all noteworthy uses of military force by the United States since establishment of the republic.

Historical Overview

The historical record indicates that the United States has never, to date, engaged in a "preemptive" military attack against another nation. Nor has the United States ever attacked another nation militarily prior to its first having been attacked or prior to U.S. citizens or interests first having been attacked, with the singular exception of the Spanish-American War. The Spanish-American War is unique in that the principal goal of United States military action was to compel Spain to grant Cuba its political independence. An act of Congress passed just prior to the U.S. declaration of war against Spain explicitly declared Cuba to be independent of Spain, demanded that Spain withdraw its military forces from the island, and authorized the president to use U.S. military force to achieve these ends. 2 Spain rejected these demands, and an exchange of declarations of war by both countries soon followed. 3 Various instances of the use of force are discussed below that could, using a less stringent definition, be argued by some as historic examples of preemption by the United States. The final case, the Cuban missile crisis of 1962, represents a threat situation which some may argue had elements more parallel to those presented by Iraq today -- but it was resolved without a "preemptive" military attack by the United States.

The circumstances surrounding the origins of the Mexican War are somewhat controversial in nature -- but the term "preemptive" attack by the United States does not apply to this conflict. During, and immediately following the First World War, the United States, as part of allied military operations, sent military forces into parts of Russia to protect its interests, and to render limited aid to anti-Bolshevik forces during the Russian civil war. In major military actions since the Second World War, the President has either obtained congressional authorization for use of military force against other nations, in advance of using it, or has directed military actions abroad on his own initiative in support of multinational operations such as those of the United Nations or of mutual security arrangements like the North Atlantic Treaty Organization (NATO). Examples of these actions include participation in the Korean War, the 1990-1991 Persian Gulf War, and the Bosnian and Kosovo operations in the 1990s. Yet in all of these varied instances of the use of military force by the United States, such military action was a "response," after the fact, and was not "preemptive" in nature.

Central American and Caribbean Interventions

This is not to say that the United States has not used its military to intervene in other nations in support of its foreign policy interests. However, U.S. military interventions, particularly a number of unilateral uses of force in the Central America and Caribbean areas throughout the 20th century, were not "preemptive" in nature. What led the United States to intervene militarily in nations in these areas was not the view that the individual nations were likely to attack the United States militarily. Rather, these U.S. military interventions were grounded in the view that they would support the Monroe Doctrine, which opposed interference in the Western hemisphere by outside nations. U.S. policy was driven by the belief that if stable governments existed in Caribbean states and Central America, then it was less likely that foreign countries would attempt to protect their nationals or their economic interests through their use of military force against one or more of these nations.

Consequently, the United States, in the early part of the 20th century, established through treaties with the Dominican Republic, in 1907, 4 and with Haiti, in 1915, 5, the right for the United States to collect and disperse customs income received by these nations, as well as the right to protect the receiver general of customs and his assistants in the performance of his duties. This effectively created U.S. protectorates for these countries until these arrangements were terminated during the administration of President Franklin D. Roosevelt. Intermittent domestic insurrections against the national governments in both countries led the U.S. to utilize American military forces to restore order in Haiti from 1915-1934 and in the Dominican Republic from 1916-1924. But the purpose of these interventions, buttressed by the treaties with the United States, was to help maintain or restore political stability, and thus eliminate the potential for foreign military intervention in contravention of the principles of the Monroe Doctrine.

Similar concerns about foreign intervention in a politically unstable Nicaragua led the United States in 1912 to accept the request of its then-President Adolfo Diaz to intervene militarily to restore political order there. Through the Bryan-Chamorro treaty with Nicaragua in 1914, the United States obtained the right to protect the Panama Canal, and its proprietary rights to any future canal through Nicaragua as well as islands leased from Nicaragua for use as military installations. This treaty also granted to the United States the right to take any measure needed to carry out the treaty's purposes. 6 This treaty had the effect of making Nicaragua a quasi-protectorate of the United States. Since political turmoil in the country might threaten the Panama Canal or U.S. proprietary rights to build another canal, the United States employed that rationale to justify the intervention and long-term presence of American military forces in Nicaragua to maintain political stability in the country. U.S. military forces were permanently withdrawn from Nicaragua in 1933. Apart from the above cases, U.S. military interventions in the Dominican Republic in 1965, Grenada in 1983, and in Panama in 1989 were based upon concerns that U.S. citizens or other U.S. interests were being harmed by the political instability in these countries at the time U.S. intervention occurred. While U.S. military interventions in Central America and Caribbean nations were controversial, after reviewing the context in which they occurred, it is fair to say that none of them involved the use of "preemptive" military force by the United States7

Covert Action

Although the use of "preemptive" force by the United States is generally associated with the overt use of U.S. military forces, it is important to note that the United States has also utilized "covert action" by U.S. government personnel in efforts to influence political and military outcomes in other nations. The public record indicates that the United States has used this form of intervention to prevent some groups or political figures from gaining or maintaining political power to the detriment of U.S. interests and those of friendly nations. For example, the use of "covert action" was widely reported to have been successfully employed to effect changes in the governments of Iran in 1953, and in Guatemala in 1954. Its use failed in the case of Cuba in 1961. The general approach in the use of a "covert action" is reportedly to support local political and military/paramilitary forces in gaining or maintaining political control in a nation, so that U.S. or its allies' interests will not be threatened. None of these activities has reportedly involved significant numbers of U.S. military forces because, by their very nature, "covert actions" are efforts to advance an outcome without drawing direct attention to the United States in the process of doing so. 8 Such previous clandestine operations by U.S. personnel could arguably have constituted efforts at "preemptive" action to forestall unwanted political or military developments in other nations. But given their presumptive limited scale compared to those of major conventional military operations, it seems more appropriate to view U.S. "covert actions" as adjuncts to more extensive U.S. military actions. As such, prior U.S. "covert actions" do not appear to be true case examples of the use of "preemptive" military force by the United States.

Cuban Missile Crisis of 1962

The one significant, well documented, case of note, where "preemptive" military action was seriously contemplated by the United States, but ultimately not used, was the Cuban missile crisis of October 1962 . When the United States learned from spy-plane photographs that the Soviet Union was secretly introducing nuclear-capable, intermediate-range ballistic missiles into Cuba, missiles that could threaten a large portion of the Eastern United States, President John F. Kennedy had to determine if the prudent course of action was to use U.S. military air strikes in an effort to destroy the missile sites before they became operational, and before the Soviets or the Cubans became aware that the U.S. knew they were being installed. While the military "preemption" option was considered, after extensive debate among his advisors on the implications of such an action, President Kennedy undertook a measured but firm approach to the crisis that utilized a U.S. military "quarantine" of the island of Cuba to prevent further shipments from the Soviet Union of military supplies and material for the missile sites, while a diplomatic solution was aggressively pursued. This approach was successful, and the crisis was peacefully resolved. 9



1. See speeches of President George W. Bush at West Point on June 1, 2002 at http://www.whitehouse.gov/news/releases/2002/06/20020601-3.html; and the President's United Nations. speech of September 12, 2002, at
http://www.whitehouse.gov/news/releases/2002/09/20020912-I.html; Washington Post,
June 2, 2002, p. A1; Washington Post, September 13, 2002, p.Al.  Return to the text

2. Joint Resolution of April 20, 1898 [Res. 241 30 Stat. 738.]  Return to the text

3. There was no direct military attack by Spain against the United States prior to the exchange of declarations of war by the nations, and initiation of hostilities by the United States in 1898. See "Declarations of War and Authorizations for the Use of Military Force: Background and Legal Implications," CRS Report RL31133, by David M. Ackerman and Richard F. Grimmett. A notable event, the sinking of the U.S.S. Maine in Havana harbor, provided an additional argument for war against Spain for those advocating it in the United States. The actual cause of the sinking of the U.S.S. Maine in Havana harbor, even today, has not been definitively established. More recent scholarship argues that it was most likely not due to an external attack on the ship, such as the use of a mine by an outside party, but due to an internal explosion.  Return to the text

4. 7 UST 196.  Return to the text

5. 8 UST 660.  Return to the text

6. 10 UST 379.  Return to the text

7. For an excellent background discussion of U.S. policy toward the Caribbean and Central American nations during the first half of the 20th century see: Samuel Flagg Bemis, A Diplomatic History of the United States. New York. Holt, Rinehart and Winston, Inc. 1965, pp. 519-538. For a detailed historical study that provides valuable insights and commentary on U.S. actions taken toward Caribbean and Central American countries see chapters 9, 11, and 12 in Samuel Flagg Bemis, The Latin American Policy of the United States. New York. Harcourt, Brace & World, 1943. [reprinted in paperback in New York, by W. W. Norton & Company, Inc., 1967].  Return to the text

8. Section 503(e) of the National Security Act of 1947, as amended, defines covert action as "An activity or activities of the United States Government to influence political, economic, or military conditions abroad, where it is intended that the role of the United States Government will not be apparent or acknowledged publicly."  Return to the text

9. For detailed background regarding the issues surrounding the possible use of "preemptive" military force against the Soviet missile sites being established in Cuba, and the deliberative process engaged in by President Kennedy and his key advisors, see the published transcripts of tape recordings made during their White House meetings in The Kennedy Tapes: Inside the White House during the Cuban Missile Crisis. Ernest R. May and Philip D. Zelikow (eds.). Cambridge, Massachusetts. Harvard University Press, 1997.  Return to the text


The opinions expressed in this article are those of the author and do not necessarily reflect the views or policies of the U.S. Government.

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