Inter‐American Treaty of Reciprocal Assistance (1947).The United States signed the Inter‐American Treaty of Reciprocal Assistance—popularly known as the Rio Treaty—with the twenty Latin American nations in 1947 in Brazil. This regional security pact, permitted under Article 51 of the United Nations Charter, incorporated the principle that an attack against one was to be considered an attack against all. Signatories would decide by a two‐thirds majority what kind of collective action might be taken against aggression. No nation would be required, however, to use force without its consent. The treaty continued the military cooperation that had characterized inter‐American relations during World War II. The Rio Treaty was also a Cold War pact aimed at the Soviet Union.

In practice, the treaty has been largely invoked, in conjunction with the consultative organs of the Organization of the American States (1948), to resolve intrahemispheric controversies, such as the dispute between Costa Rica and Nicaragua in 1955 or the Dominican Republic's attack on Venezuelan president Rómulo Betancourt in 1960. President John F. Kennedy did cite the Rio Treaty in justifying his quarantine order during the Cuban Missile Crisis of 1962. But usually when the United States decided that the Soviet Union threatened its hemispheric interests, Washington bypassed the treaty and acted unilaterally, as in Guatemala (1954), Cuba (1961), the Dominican Republic (1965), Chile (1970–73), and Nicaragua (1980s). The United States also refused the request of Latin American nations to invoke the Rio Treaty against Great Britain during the 1982 Anglo‐Argentine war over the Falkland Islands.
[See also Caribbean and Latin America, U.S. Military Involvement in the.]

Bibliography

J. Lloyd Mecham , The United States and Inter‐American Security, 1889–1960, 1961.
Gordon Connell‐Smith , The Inter‐American System, 1966.

Stephen G. Rabe