What was the economic factor of American involvement in Latin America during the Cold War?

During the Cold War, the United States was deeply involved in the political and economic affairs of the countries of Latin America.  They often supported brutal dictatorships or helped rebels to overthrow stable governments.  The primary purpose of this involvement was to prevent other countries in Latin America from establishing communist governments.  These communist governments would inevitably be friendly towards the Soviet Union in the same fashion as Fidel Castro in Cuba.  The United States had a strong economic motivation for being involved in Latin America in that it was a source of vital raw materials and cash crops.  The United States always had a strong trade advantage when dealing with Latin American countries.  If a country was to establish a communist-style government, it would no longer be interested in trading with the United States.