Rio Treaty

Rio Treaty (Inter-American Treaty of Reciprocal Assistance), signed Sept. 2, 1947, and originally ratified by all 21 American republics. Under the treaty, an armed attack or threat of aggression against a signatory nation, whether by a member nation or by some other power, will be considered an attack against all (see Pan-Americanism ). The treaty provides that no member can use force without the unanimous consent of the other signatories, but that other measures against aggressors may be approved by a two-thirds majority. It differs from previous inter-American treaties in that it is a regional treaty within a larger international organization; it recognizes the higher authority of the Security Council of the United Nations.

Inter-American Treaty of Reciprocal Assistance an agreement signed by the United States and twenty Latin American nations in September 1947, during the Cold War, to establish regional collective defense against Communist aggression. A pact permitted under Article 51 of the United Nations Charter, it included the principle that an attack against one was considered an attack against all. Also known as the Rio Treaty.

Inter-American Treaty of Reciprocal Assistance (Rio de Janeiro Treaty) (Sept. 1947) A security agreement signed and ratified by all of the 21 American republics, which formalized and extended the informal security pact against Germany and Japan during World War II in response to the emerging Cold War. A pact against aggression from outside and within the alliance, it was regarded by most members as a multilateral mechanism for the maintenance of peace and stability across the region, whereas the US considered it to be another bloc against the spread of Communism. It was invoked in a number of regional conflicts, such as those between Nicaragua and Costa Rica in 1949, 1955, and 1959. At the same time, it has also been used to justify US intervention in the member states' domestic affairs, such as those in Grenada (1983) or Panama (1989). Since 1948 it has been complemented by the formation of a political alliance, the OAS.