Instances of Use of United States Armed Forces Abroad, 1798-2015 [October 15, 2015] [open pdf - 888KB]
"This report lists hundreds of instances in which the United States has used its Armed Forces abroad in situations of military conflict or potential conflict or for other than normal peacetime purposes. It was compiled in part from various older lists and is intended primarily to provide a rough survey of past U.S. military ventures abroad, without reference to the magnitude of the given instance noted. The listing often contains references, especially from 1980 forward, to continuing military deployments, especially U.S. military participation in multinational operations associated with NATO or the United Nations. Most of these post-1980 instances are summaries based on presidential reports to Congress related to the War Powers Resolution. A comprehensive commentary regarding any of the instances listed is not undertaken here. The instances differ greatly in number of forces, purpose, extent of hostilities, and legal authorization. Eleven times in its history, the United States has formally declared war against foreign nations. These 11 U.S. war declarations encompassed five separate wars: the war with Great Britain declared in 1812; the war with Mexico declared in 1846; the war with Spain declared in 1898; the First World War, during which the United States declared war with Germany and with Austria-Hungary during 1917; and World War II, during which the United States declared war against Japan, Germany, and Italy in 1941, and against Bulgaria, Hungary, and Rumania in 1942."
CRS Report for Congress, R42738
Federation of American Scientists: http://www.fas.org/sgp/crs/index.html