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Rio Conference (1947)

Rio Conference (1947)

The Inter-American Conference for the Maintenance of Continental Peace and Security, held near Rio de Janeiro from 15 August to 2 September 1947, produced a multilateral mutual defense treaty. This Rio Treaty, or Inter-American Treaty of Reciprocal Assistance, bound the United States and the signatory Latin American republics in a mutual defense system.

Acting under Article 50 of the United Nations Charter, representatives from nineteen of the twenty-one republics of the Western Hemisphere (Nicaragua and Ecuador did not send representatives) declared that an attack on any member state by either an outside force or another member state would obligate all member states to come to the aid of the state under attack. Member states agreed to settle their differences peacefully and to abide by decisions and sanctions imposed by a vote of their foreign ministers.

The Rio Conference of 1947 completed the work begun by the Act of Chapultepec (1945), which had excluded Argentina because of its support of the Axis powers during World War II. But by 1947 the United States, motivated by the fear of active infiltration of Soviet communism moved to secure the Western Hemisphere, electing to strengthen inter-American bonds by filling the gap of an incomplete mutual security pact. The resulting Rio Treaty was the first permanent alliance ratified by the United States that effectively altered the unilateral Monroe Doctrine and created a multilateral commitment to the security of the hemisphere. This Rio Treaty led to the charter of the Organization of American States (OAS), drafted in Bogotá, Colombia, in 1948, which set up a permanent political organization to carry out the terms of the Rio Treaty and end regional disputes before they could explode into open warfare. The Rio Conference and the Bogotá meeting also attempted to mitigate regional hostilities resulting from Latin American desires for political independence and autonomy while sharing a hemisphere with the powerful neighbor to the north.


Leonard, Thomas, and John F. Bratzel. Latin America during World War II. Lanham: Rowman & Littlefield, 2007.

Sheinin, David. Beyond the Ideal: Pan Americanism in Inter-American Affairs. Westport: Greenwood Press, 2000.

Vázquez García, Humberto. De Chapultepec a la OEA: Apogeo y crisis del panamericanismo. La Habana: Editorial de Ciencias Sociales, 2001.

                                  Lesley R. Luster

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