[1] 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.

However, Latin American countries were largely sidelined from the Allied discussions of a postwar security order, held at Dumbarton Oaks from August to October 1944.

It also shaped Latin American pressure during the United Nations conference in San Francisco for clauses in the UN Charter to facilitate regional collective defense, under Article 51.

The American concern, alongside that of some countries in South America regarding Peronism raised the possibility of including collective intervention to preserve democracy in the security conference.

As revolutionary and nationalist governments spread through Latin America through the 1950s and 1960s, the fear of a shared enemy that was experienced during WWII dissipated and the idea of defensive cooperation became strained.

[17] According to Slater, many Latin American governments participating in the Treaty sought "to insulate the hemisphere from rather than involve it in world conflict", though the United States pushed the smaller countries towards confrontation with its ideological adversaries.

[18] Though the Cold War overtones of the Rio Treaty became increasingly evident, during the immediate post-war years, Long argues that it was more closely tied to pre-WWII regional antecedents and, even, Latin American diplomatic pressure.

The sixteen countries were Argentina, Belize, Bolivia, Chile, Colombia, Cuba, Ecuador, Grenada, Guyana, Jamaica, Nicaragua, Panama, Peru, St. Lucia, Suriname, and Trinidad-Tobago.

[21] During a speech he made on 7 September 2001, the Mexican president, Vicente Fox Quesada, pointed out the necessity of having a multidimensional and modern security structure that responds to the real needs of the American hemisphere.

[25][26] On 5 June 2012, Bolivarian Alliance for the Americas (ALBA) countries Bolivia, Ecuador, Nicaragua, and Venezuela, under the leadership of leftist governments, initiated the retirement from the TIAR,[27][28] a decision which the Obama administration described as "unfortunate" but respected.