Following the 1973 Chilean coup d'état, an armed leftist resistance movement against Augusto Pinochet's dictatorship developed until 1990 when democracy was restored. This conflict was part of the South American theater in the Cold War, with the United States backing the Chilean military and the Soviet Union backing the guerrillas. The main armed resistance groups of the period were the Revolutionary Left Movement (MIR) and Frente Patriótico Manuel Rodríguez (FPMR), the armed wing of the Communist Party of Chile. These groups had a long-standing rivalry, including over Marxist orthodoxy.