Louis Dalrymple in the context of "Art Students League of New York"

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.

President James Monroe first articulated the doctrine on December 2, 1823, during his seventh annual State of the Union Address to Congress (though it was not named after him until 1850). At the time, nearly all Spanish colonies in the Americas had either achieved or were close to independence. Monroe asserted that the New World and the Old World were to remain distinctly separate spheres of influence, and thus further efforts by European powers to control or influence sovereign states in the region would be viewed as a threat to U.S. security. In turn, the United States would recognize and not interfere with existing European colonies nor meddle in the internal affairs of European countries.