Monroe Doctrine

In his annual message to Congress on 2 December 1823, President James Monroe warned the powers of Europe that the Americas were closed to further colonisation and that any attempt to oppress the newly independent states there would be seen as unfriendly to the United States. The principle, later called the Monroe Doctrine, began as a statement with little force behind it. Over the following two centuries it grew into a central idea of American foreign policy, used to justify both the defence of the hemisphere and repeated US intervention in Latin America.

By the early 1820s most of Spain's mainland American colonies had won, or were close to winning, their independence in the Spanish American wars of independence. After the Congress of Vienna, the conservative monarchies of Prussia, Austria and Russia formed the Holy Alliance, and the United States feared they might help restore Spanish rule. Russia's decree of 1821 claiming the Pacific Northwest coast and barring foreign ships added a more direct worry. Britain, eager to keep the new markets open to its trade, proposed a joint declaration, but American leaders preferred to act alone.

The text was drafted mainly by Secretary of State John Quincy Adams. Its two key passages declared that the American continents were no longer open to colonisation by European powers, and that any European effort to extend its political system to the hemisphere would be regarded as a danger to American peace and safety. In return, the United States would leave existing European colonies alone and stay out of Europe's own affairs. The policy was not named after Monroe until 1850.

With only a small army and navy, the United States could not enforce the policy, and European statesmen largely ignored it; Austria's Metternich condemned it as an act of revolt. In practice it was the Royal Navy that kept other powers out, because British interests happened to coincide. Independence leaders such as Simón Bolívar welcomed Monroe's words, though some, like the Chilean minister Diego Portales, suspected American motives. The United States took no action when Britain reasserted control over the Falkland Islands in 1833, or when France and Britain blockaded the Río de la Plata.

The doctrine gained weight after the American Civil War. French forces under Napoleon III had installed Maximilian as emperor of Mexico in the 1860s; once the war ended, Washington pressed France to withdraw, and its troops left. In 1895 the United States cited the doctrine to force Britain to arbitrate a border dispute with Venezuela, a sign of its new confidence. The Spanish–American War of 1898 ended Spanish rule in Cuba and Puerto Rico.

In 1904 Theodore Roosevelt added a corollary claiming a right to intervene in Latin American countries guilty of what he called chronic wrongdoing, so that European creditors would have no excuse to do so. It caused outrage across the region and was used to justify a string of occupations, including Haiti from 1915 to 1935, the Dominican Republic from 1916 to 1924, and Nicaragua for much of 1912 to 1933. The Good Neighbor policy of the 1930s turned away from such interventions.

During the Cold War, US officials invoked the doctrine against Soviet influence, notably John F. Kennedy during the 1962 crisis over Soviet missiles in Cuba. In 2013 Secretary of State John Kerry declared the era of the doctrine over, but later administrations revived the language, and the 2025 National Security Strategy explicitly called for reasserting it. Critics have long argued that a doctrine against European empire became a charter for American dominance of the hemisphere.

Our 1815 map shows much of the Americas still within the Spanish Empire, while the 1878 map shows the independent republics of Latin America that the doctrine claimed to protect.