When the United States government decides to deploy the military, it says it does so to protect American interests and lives. That's according to a report that examined over 300 instances of U.S. troop deployments between 1798 and 2014 -- including instances in Florida, Texas, Hawaii and Oregon.
According to the Congressional Research Service, released last month, the specifics behind sending troops abroad vary. Five times the government was "punishing natives" in Sumatra, Fiji and Korea. A dozen times armed forces have had to deal with pirates, mostly in the 19th century but also once in 2012 in Somalia.
Occasionally the deployed forces weren't there to fight at all. In 1941 Iceland was taken under the "protection of the United States, with consent of its government, for strategic reasons." Humanitarian, medical, security and disaster assistance has been cited 20 times since 1948. The map below shows the most recent deployment of armed forces for each country. Click on a country to see why troops were sent abroad.
The United States has had only five official wars (though we have formally declared war on a foreign nation 11 times). The Vietnam War, Persian Gulf war, War in Afghanistan and Iraq War were all military engagements authorized by Congress. The Korean War and the U.S. involvement in Kosovo are examples of military engagements that were authorized by the United Nations but funded by the U.S. Congress. A look at the graphic below -- which shows how many times per year armed forces are deployed, as well as whether the United States was at war at the time -- shows putting boots on the ground is fairly independent of a declaration of war. Notably, there is little correlation between the president's political party and the number of times troops were deployed.