America’s official wars


The United States of America has only officially declared war on five occasions in over two centuries of its existence. Formal declarations were made by Congress in 1812, 1846, 1898, 1917 and 1941. So does this mean the US has spent most of its history at peace? And what about the Korean, Vietnam, Gulf, Iraqi and Afghanistan wars?

Under Article One of Section Eight of the Constitution of the United States, Congress is given the power to declare War. Formal declarations of war have been made in the following conflicts:

  • The War of 1812 (18 June 1812);
  • Mexican-American War (13 May 1846);
  • Spanish-American War (25 April 1898);
  • World War I (6 April 1917 (Germany) and 7 December 1917 (Austria-Hungary); and
  • World War II (8 December 1941 (Japan), 11 December 1941 (Germany and Italy) and 5 June 1945 (Bulgaria, Hungary and Romania).

Given the limited number of times formal declarations of war have been made, how was the US been engaged in so many military conflicts over the centuries? A little bit of semantics and a lot of power politics between the legislature and executive have provided room for military clashes. 

In some cases, Congress has authorised extended military combat and the deployment of the United States’ armed forces. Such authorisations have covered conflicts such as the invasions of Afghanistan and Iraq, the Gulf War and the support of South Vietnam in the Vietnam War.

Other conflicts have been authorised by a United Nations Security Council Resolutions and funded by Congress. UN-backed military engagements have included interventions in Korea, Libya and Haiti.

Finally, there are a bunch of conflicts that have not involved any Congressional oversight or sanction. Wars against native American tribes, the Philippines and the bombing of Yugoslavia have all been undertaken under presidential sanction but without the approval of Congress.