The context is the Cold War. Salvador Allende is considered a socialist for his efforts in community organizing and his promise to nationalize parts of Chile's energy sector. He is  perceived as a distinct threat to US business hegemony in the region--perhaps rightfully, at least from an economic perspective.

President Richard Nixon ordered the CIA to "make the economy scream" in Chile to "prevent Allende from coming to power or to unseat him." With documented U.S. support, General Pinochet assumed power and ended Allende's democratically elected Popular Unity government. During the air raids and ground attacks that preceded the coup, Allende gave his last speech where he vowed to stay in the presidential palace.  He either committed suicide or was murdered there by one of Pinochet's soldiers.

If that single event had been the only violence to mark Pinochet's rise to power, it would have been bad enough, but nothing especially compelling-especially in the context of South American politics. But after the coupe, Pinochet established a military dictatorship that ruled Chile until 1990 and that was marked by some of the worst human rights violations on Earth--systematic torture, imprisonment, disappearances and outright assasinations and murder--in the tens of thousands -- such that they dwarf the events of 9/11 2001 in the United States.

During his reign, the Chilean junta moved to crush left-wing opposition all across Chile. It embarked on a murderous campaign against opponents and perceived leftists in the country. As a result, according to the Rettig Commission, approximately 3,000 people are known to have been killed, 27,000 were incarcerated and in a great many cases tortured.

Many exiled themselves to neighboring Argentina or other countries in the Southern Cone of South America, but Operation Condor, with tacit US approval, murdered the exiles even in foreign countries.

According to Roger Burbach:

http://www.counterpunch.org/burbach09112003.html

Prior to the attack on the Pentagon on September 11, 2001 the most sensational foreign-lead terrorist action in the capitol had been carried out by a team of operatives sent by the Pinochet regime. On September 21, 1976, agents of the Chilean secret police organization, DINA, detonated a car bomb just blocks from the White House, killing a leading opponent of Pinochet's, Orlando Letelier, and his assistant Ronni Moffitt. Letelier, whom I spoke to at the Institute for Policy Studies in Washington D.C. before his death, was a man deeply committed to democracy and a more humane world who had served at the highest levels of the Allende government. These assassinations were linked to the first international terrorist network in the Western Hemisphere, known as Operation Condor.Begun in 1974 at the instigation of the Chilean secret police, Operation Condor was a sinister cabal comprised of the intelligence services of at least six South American countries that collaborated in tracking, kidnapping and assassinating political opponents. Based on documents divulged under the Chile Declassification Project of the Clinton administration, it is now recognized that the CIA knew about these international terrorist activities and may have even abetted them. After the murders of Letelier-Moffitt in Washington D.C., the CIA appears to have concluded that Condor was a rogue operation and may have tried to contain its activities. However, the network of Southern Cone military and intelligence operations continued to act throughout Latin America at least until the early 1980s. Chilean and Argentine military units assisted the dictator Anastasio Somoza in Nicaragua and helped set up death squads in El Salvador. Argentine units also aided and supervised Honduran military death squads that began operating in the early 1980s with the direct assistance and collaboration the CIA

In fact, the archives of Operation Condor discovered by José Fernández, a Paraguayan judge on December 22, 1992 counted 50,000 persons murdered, 30,000 "desaparecidos" and 400,000 incarcerated. When  U.S. citizens remember with horror the events of 9/11 2001, it's well to remember that the terror attacks that stemmed from the Chilean coupe  of 1973 -which we supported--were exponentially more deadly than the 9/11 attacks that occurred here.

Related Document info at
http://www.gwu.edu/~nsarchiv/NSAEBB/NSAEBB8/nsaebb8i.htm

More info on Operation Condor at:
http://www.spartacus.schoolnet.co.uk/JFKcondor.htm

Cross posted at http://www.dailykos.com