In 1823, President James Monroe explained to Congress the U.S. policy on the new political order developing in the rest of the Americas and the role of Europe in the Western Hemisphere.

The statement was known as the Monroe Doctrine. The Great Powers of Europe largely ignored it. However, the Monroe Doctrine became a longstanding principle of U.S. foreign policy. Monroe and his Secretary of State John Quincy Adams drew upon American diplomatic ideals, such as disentanglement from European affairs, and defense of neutral rights as expressed in Washington’s Farewell Address and Madison’s stated rationale for the War of 1812. The three main concepts of the doctrine were to separate spheres of influence for the Americas and Europe, non-colonization, and non-intervention. These concepts signified a clear break between the New World and the autocratic realm of Europe. Monroe’s administration warned the imperial European powers not to interfere in the affairs of the newly independent Latin American states or potential U.S. territories. While Americans objected to European colonies in the New World, they also wanted to increase United States influence and trade throughout the Americas.

The British were also interested in stopping Spanish colonialism, with all the trade restrictions mercantilism imposed. Earlier in 1823, British Foreign Minister George Canning suggested to Americans that the two nations issue a joint declaration to deter any other power from intervening in Central and South America. Secretary of State John Quincy Adams, however, opposed cooperation with Great Britain, which might limit United States expansion in the future. He also argued that the British were not committed to recognizing the Latin American republics and probably had imperial motivations themselves.

The bilateral statement proposed by the British thus became a unilateral declaration by the United States. Monroe stated: “The American continents … are henceforth not to be considered as subjects for future colonization by any European powers.” He outlined two separate spheres of influence: the Americas and Europe. The independent lands of the Western Hemisphere would be the domain of the United States. In exchange, the United States agreed to avoid involvement in the political affairs of Europe.

By the mid-1800s, Monroe’s declaration, combined with ideas of Manifest Destiny, provided precedent and support for U.S. expansion on the American continent. In the late 1800s, U.S. economic and military power enabled it to enforce the Monroe Doctrine.

Source: Monroe Doctrine, 1823
Office of the Historian, U.S. Department of State