During the Spanish Transición, military juntas took power by means of coups in Chile and Argentina. After grave human rights violations and mass crimes, the military presidents ceded power in the 1980s – and amnestied themselves, following the Spanish model.

"In view of the terrible social and moral crisis that beleaguers the country [and] the government's inability to control the chaos [...], the armed and police forces stand united to begin their historic and responsible mission to liberate the fatherland." With these words, the military junta led by Commander-in-Chief of the Chilean Army Augusto Pinochet legitimized its coup against Chile's socialist President Salvador Allende on September 11, 1973. Three years earlier, Allende had been elected to office by a narrow majority. Fighting poverty with nationalizations and a generous social policy, he would at the same time plunge the country into a severe economic crisis via galloping inflation and estrange Chile from the United States. Washington thus immediately recognized Pinochet as legitimate president in 1973. Three years later, the military also seized power in Argentina. Here, it was the vacuum left by the death of President Juan Domingo Perón, a growing economic crisis, and increased assassinations by the leftist urban guerrillas Montoneros that prompted the military around General Jorge Videla to place Perón's wife, vice president and successor, Isabel Martínez de Perón, under house arrest.

Especially in the months immediately following the respective takeovers, the junta governments in Chile and Argentina committed grave human rights violations and mass crimes. Pinochet – an ardent admirer of Franco, who was one of the few state guests to attend the Spanish dictator's funeral in 1975 – primarily used the DINA secret police to kidnap, torture and execute disfavored opposition figures. In Argentina, President Videla declared as subversives all those who would undermine the country's Christian values with "ideas contrary to our civilization." Here, too, dissenters were kidnapped, tortured, and killed. In Chile, about 3,000 of 30,000 torture victims died. In Argentina, between 6,000 and 30,000 people disappeared. Determining an exact figure is made more difficult by the practice of "disappearing," which involved abductions without certainty regarding the whereabouts of those detained. While Pinochet based his legitimacy on a temporary improvement in Chile's economic situation through monetary structural reforms as well as on manipulated referendums, the Argentine military junta's situation remained precarious throughout due to the country’s unstable economic situation. Major publicity stunts such as the hosting of the 1978 World Cup could hardly distract from this fact.

With the occupation of the Falkland Islands off the Argentine coast – a British colony since 1833 – the new Argentine president, General Leopoldo Galtieri, aimed at unleashing a wave of national euphoria in 1982. However, the successful British counter-operation dealt a death blow to the military junta. In 1983, Reynaldo Bignone, Argentina's last military president, called free elections. An amnesty law guaranteed the former rulers immunity from prosecution. In Chile, President Pinochet wanted to boost his legitimacy in 1988 by holding another referendum, which he surprisingly lost. Despite the free elections of 1989, Pinochet, who secured himself the offices of army chief and senator for life, remained an influential figure in Chilean politics. Although two truth commissions in 1991 and 2004 investigated the crimes of the Pinochet years, there were no legal consequences for the former ruler, who died in 2006, since a 1978 amnesty law protected him from prosecution. The situation was different in Argentina, where the CONADEP truth commission presented a dossier of human rights violations in 1984. Based on this report, the military junta’s decision-makers – including Videla, Galtieri and Bignone – were sentenced to lengthy prison terms in 1985.