In the 1950s, 60s and 70s, social movements in Latin America began to challenge stratified class systems that were often hangovers from colonial rule. Leftwing movements and populist parties gained support, and sometimes power, in countries including Brazil, Argentina, Nicaragua and Bolivia. In Chile, Salvador Allende became the world’s first democratically elected Marxist president in 1970.
In the context of the Cold War, the U.S. viewed those developments down south as a threat to the global balance of power: American security forces did not want more of its neighbors to become allies of the U.S.S.R. They also wanted to protect American businesses and assets in the region, fearing that any new leftwing governments would follow the example of Cuba after its revolution and throw foreign powers out of the country.
To help stop any of that from happening, the U.S. used a range of interventionist methods. In the 1960s, State Department officials and CIA agents were intimately involved in training and assisting Guatemalan security forces, who killed thousands of civilians during a civil war with leftist rebels against the right-wing government. In the 1970s in Chile, the CIA attempted to thwart Allende’s ascent and later lent support to the General Augusto Pinochet, the right-wing military dictator who overthrew him. Pinochet’s regime murdered 3,065 of its citizens and committed human rights abuses against almost 40,000. In the 1980s in Nicaragua, the U.S. backed the right-wing Contra rebels to take on the socialist Sandinista government, leading to a decade of violent struggle.
https://www.google.com/amp/amp.timeinc.net/time/5512005/venezuela-us-intervention-history-latin-america
