President Theodore Roosevelt announced the Roosevelt Corollary to the Monroe Doctrine, justifying the exercise of "international police power" by the U.S. in the Western Hemisphere.

Theodore Roosevelt Jr., also known as Teddy or T. R., was the 26th president of the United States, serving from 1901 to 1909. Roosevelt previously was involved in New York politics, including serving as the state's 33rd governor for two years. He served as the 25th vice president under President William McKinley for six months in 1901, assuming the presidency after McKinley's assassination. As president, Roosevelt emerged as a leader of the Republican Party and became a driving force for anti-trust and Progressive Era policies.

In the history of United States foreign policy, the Roosevelt Corollary was an addition to the Monroe Doctrine articulated by President Theodore Roosevelt in his 1904 State of the Union Address, largely as a consequence of the Venezuelan crisis of 1902–1903. The corollary states that the United States could intervene in the internal affairs of Latin American countries if they committed flagrant wrongdoings that "loosened the ties of civilized society".

The Monroe Doctrine is a United States foreign policy position that opposes European colonialism in the Western Hemisphere. It holds that any intervention in the political affairs of the Americas by foreign powers is a potentially hostile act against the United States. The doctrine was central to American grand strategy in the 20th century.