Declarations of War and Authorizations for the Use of Military Force: Historical Background and Legal Implications

From the Washington Administration to the present, Congress and the President have enacted 11 separate formal declarations of war against foreign nations in five different wars. Each declaration has been preceded by a presidential request either in writing or in person before a joint session of Congress. The reasons cited in justification for the requests have included armed attacks on U.S. territory or its citizens and threats to U.S. rights or interests as a sovereign nation. Congress and the President have also on a number of occasions enacted authorizations for the use of force instead of declarations of war. Most commonly, such measures have authorized the use of force against either a named country or unnamed hostile nations in a given region. In most cases, the President has requested the authority, but Congress has sometimes given the President less than what he asked for. In contrast to the declarations of war, not all authorizations for the use of force have resulted in actual combat. Both declarations and authorizations require the signature of the President to become law. This report provides historical background on the enactment of declarations of war and authorizations for the use of force and analyzes their legal effects under international and domestic law. It also sets forth their texts in two appendices. Because the statutes that confer standby authority on the President and the executive branch potentially play such a large role in an armed conflict to which the United States is a party, the report includes an extensive listing and summary of the statutes that are triggered by a declaration of war, a declaration of national emergency, andor the existence of a state of war. The report concludes with a summary of the congressional procedures applicable to the enactment of a declaration of war or authorization for the use of force and to measures under the War Powers Resolution.