Inter-American Treaty of Reciprocal Assistance

The Inter-American Treaty of Reciprocal Assistance (commonly known as the Rio Treaty, the Rio Pact, the Treaty of Reciprocal Assistance, or by the Spanish-language acronym TIAR from Tratado Interamericano de Asistencia Recíproca) is an intergovernmental collective security agreement signed in 1947 in Rio de Janeiro, Brazil, at a meeting of the American states.

The central principle contained in its articles is that an attack against one is to be considered an attack against them all; this was known as the "hemispheric defense" doctrine. Despite this, several members have breached the treaty on multiple occasions.

The treaty was initially created in 1947 and came into force in 1948, in accordance with Article 22 of the treaty. The Bahamas was the most recent country to sign and ratify it in 1982.

Background

The United States maintained a hemispheric defense policy relative to European influence under the Monroe Doctrine from 1823 onward, and became increasingly interventionist following the 1904 promulgation of the Roosevelt Corollary. During the 1930s the United States had been alarmed by Axis overtures suggesting military cooperation with Latin American governments; apparent strategic threats against the Panama Canal were of particular concern. These were discussed in a series of meetings of the International Conference of American States and at the 1936 Inter-American Conference for the Maintenance of Peace. During World War II, the American government had been able to secure support for the Allies from all individual governments in the Americas except Uruguay (which remained neutral until 22 February 1945) and Argentina (which had difficult relations with the Allied powers from 1944 to 1945 but declared war on the Axis on 27 March 1945). Some countries had signed the Declaration by United Nations in early 1942 and more had signed by the end of 1945.