On March 24, 1976, in a well-planned coup, the Argentine armed forces overthrew the government of President Isabel Martinez de Peron (1931-), who was held in "protective custody." A three-man military junta, head by General Jorge Rafael Videla (1925-), took charge and began a ruthless campaign against liberals, leftists, and political terrorists. Anyone suspected of favoring these groups was subject to arbitrary arrest, and those who had illegally profited from the former corrupt Peronist government were prosecuted. People were kidnapped on the streets and never seen again; the prisons overflowed with so-called political prisoners, and torture was common; there were no trials or pretense of legal process. An estimated 11,000 Argentines disappeared between 1976 and 1982, and the flagrant violations of human rights caused the US government under President James E. Carter, Jr. (1924-), to stop sending military aid to Argentina. Several prominent prisoners were freed and allowed to leave the country, and gradually the security forces decreased their "dirty war" activities in response to adverse worldwide public opinion. With the return to civilian government on December 10, 1983, Argentina's newly elected president Raul Alfonsin (1926-) announced plans to prosecute the nine military leaders who ruled during the "dirty war," or reign of terror, from 1976 until the restoration of democracy in 1983. After an eight-month-long trial in Buenos Aires in 1985, Videla and his navy commander, Admiral Emilo Massera (1925-), were found guilty of homicide, illegal detention, and other human rights violations and were sentenced to life imprisonment. Three codefendants, including General Roberto Eduardo Viola (1924-), who succeeded Videla as president, were found guilty of lesser charges and received sentences ranging from four and a half to 17 years. The remaining four officers were acquitted. In January 1991, Argentina's President Carlos Saul Menem (1930-), seeking to quell discontent in the military (four army uprisings had occurred since 1983), issued pardons to imprisoned military personnel, including Videla, which resulted in much public protest and outrage.