What were the objectives of the Salvadoran revolution, and how did US intervention affect it?Keen, Benjamin. A History of Latin America, Vols, I...

The roots of the Salvadorian civil war have deep roots. 
The main issue revolved around land ownership.  El Salvador relies on cash crops and the
desire for more equitable distribution of the wealth from this source led to an ongoing
struggle that began in the 1930s.

In 1979, a military junta
took over with promises of reform.  When these were not forthcoming, the main five
guerilla groups formed one organization - the FMLN (Farabundo Marti National Liberation
Front).  The authorities reacted with mass arrests and
executions.

The U.S. is said to have perpetuated the
conflict by providing aid to the Salvadorean government.  It must be remembered that
this was still the time of the Cold War and the U.S. was worried about communist
activity in Latin America.  The U.S. trained and supported the government forces who
embarked on a brutal campaign including mass murder and assasinations of key political
opponents.

The atrocities led to congressional
investigations and the end of military aid.  Even so,  U.S. military assistance arguably
led to the perpertuation of the conflict that claimed thousands of
lives.