<P> Through the Office of Public Safety, an organization dependent of the USAID and close to the CIA, the US assisted Latin American security forces, training them in interrogation methods, riot control, and sending them equipment . Dan Mitrione, in Uruguay, and Luis Posada Carriles, in Venezuela, became infamous for his systematic use of torture . </P> <P> Following the 1959 Cuban Revolution and the local implementation in several countries of Che Guevara's foco theory, the US waged a war in South America against what it called "Communist subversives", leading to support of coups against democratically elected presidents such as the backing of the Chilean right wing, which would culminate with Augusto Pinochet's 1973 Chilean coup against democratically - elected Salvador Allende . By 1976, all of South America was covered by similar military dictatorships, called juntas . In Paraguay, Alfredo Stroessner had been in power since 1954; in Brazil, left - wing President João Goulart was overthrown by a military coup in 1964 with the assistance of the US in what was known as Operation Brother Sam; in Bolivia, General Hugo Banzer overthrew leftist General Juan José Torres in 1971; in Uruguay, considered the "Switzerland" of South America, Juan María Bordaberry seized power in the 27 June 1973 coup . In Peru, leftist General Velasco Alvarado in power since 1968, planned to use the recently empowered Peruvian military to overwhelm Chilean armed forces in a planned invasion of Pinochetist Chile . A "Dirty War" was waged all over the subcontinent, culminating with Operation Condor, an agreement between security services of the Southern Cone and other South American countries to repress and assassinate political opponents, which was backed by the US government . The armed forces also took power in Argentina in 1976, and then supported the 1980 "Cocaine Coup" of Luis García Meza Tejada in Bolivia, before training the "Contras" in Nicaragua, where the Sandinista National Liberation Front, headed by Daniel Ortega, had taken power in 1979, as well as militaries in Guatemala and in El Salvador . In the frame of Operation Charly, supported by the US, the Argentine military exported state terror tactics to Central America, where the "dirty war" was waged until well into the 1990s, making hundreds of thousands "disappeared". </P> <P> With the election of President Jimmy Carter in 1977, the US moderated for a short time its support to authoritarian regimes in Latin America . It was during that year that the Inter-American Court of Human Rights, an agency of the OAS, was created . At the same time, voices in the US began to denounce Pinochet's violation of human rights, in particular after the 1976 assassination of former Chilean minister Orlando Letelier in Washington D.C. </P> <P> The inauguration of Ronald Reagan in 1981 meant a renewed support for right - wing authoritarian regimes in Latin America . In the 1980s, the situation progressively evolved in the world as in South America, despite a renewal of the Cold War from 1979 to 1985, the year during which Mikhail Gorbachev replaced Konstantin Chernenko as leader of the USSR, and began to implement the glasnost and the perestroika democratic - inspired reforms . South America saw various states returning progressively to democracy . This democratization of South America found a symbol in the OAS' adoption of Resolution 1080 in 1991, which requires the Secretary General to convene the Permanent Council within ten days of a coup d'état in any member country . However, at the same time, Washington started to aggressively pursue the "War on Drugs", which included the invasion of Panama in 1989 to overthrow Manuel Noriega, who had been a long - time ally of the US and had even worked for the CIA before his reign as leader of the country . The "War on Drugs" was later expanded through Plan Colombia in the late 1990s and the Mérida Initiative in Mexico and central america . </P>

Which of these latin american nations did the united states intervene in april of 1964