Monroe Doctrine

Monroe set out the policy in his seventh annual message to Congress on 2 December 1823. Many Latin American colonies had recently won independence, and U.S. officials feared European powers might attempt to restore colonial rule. British foreign minister George Canning had proposed a joint Anglo-American declaration against intervention, but Secretary of State John Quincy Adams opposed tying U.S. policy to Britain. The message therefore presented a unilateral U.S. position. It later became known as the Monroe Doctrine, although at the time it was part of a broader presidential address rather than a separate treaty.

The 1823 statement opposed further European colonization and intervention in the independent states of the Western Hemisphere. In return, the United States said it would not interfere in European political affairs and would not disturb European colonies already established in the Americas. The policy articulated separate spheres for Europe and the Americas, but its original language did not give the United States a formal treaty-based authority over other American states. At the time, the United States had limited means to enforce its warning; the Office of the Historian notes that European powers initially paid little attention to it.

The doctrine's influence grew as U.S. economic and military power expanded. In 1865, the United States invoked it while supporting Mexican president Benito Juárez against the French-backed Emperor Maximilian. In 1904, President Theodore Roosevelt announced a corollary asserting a U.S. role in addressing what his administration called chronic wrongdoing in the hemisphere, including circumstances that might invite European intervention. This went beyond Monroe's original warning against European action: the corollary was used to justify U.S. intervention in Latin American countries. Such interventions were viewed with misgiving by other nations in the region and contributed to strained relations with the United States.

The Monroe Doctrine became a recurring reference point in U.S. policy toward the Western Hemisphere, but its meaning was not fixed. It began as an anti-colonial warning directed at European powers and later also served as a rationale for U.S. regional predominance and intervention. The distinction between the original 1823 message and its later extensions is important: Latin American governments could welcome resistance to European recolonization while objecting to the unilateral power the United States claimed for itself. The doctrine is therefore studied both as a milestone in U.S. diplomacy and as a source of tension in inter-American relations.