United States involvement in regime change has entailed both overt and covert actions aimed at altering, replacing, or preserving foreign governments. In the latter half of the 19th century, the U.S. government undertook regime change actions mainly in Latin America and the southwest Pacific, and included the Mexican-American, Spanish-American and Philippine-American wars. At the onset of the 20th century the United States shaped or installed friendly governments in many countries including Panama, Honduras, Nicaragua, Mexico, Haiti, and the Dominican Republic.
In the aftermath of World War II, the U.S. government expanded the geographic scope of its regime change actions, as the country struggled with the Soviet Union for global leadership and influence within the context of the Cold War. Significant involvements included the 1950 Korean War, the 1953 Iranian coup d'état, the 1961 Bay of Pigs Invasion targeting Cuba, the Vietnam War, and support for the Argentinian Dirty War, but included other operations throughout the world.
Also after World War II, the United States in 1945 ratified the UN Charter, the preeminent international law document, which legally bound the U.S. government to the Charter's provisions, including Article 2(4), which prohibits the threat or use of force in international relations, except in very limited circumstances. Therefore, any legal claim advanced to justify regime change by a foreign power carries a particularly heavy burden.