How did the logic of the cold war shape American foreign policy in Central America? What kinds of regimes were supported because of this policy? With what results?

American foreign policy during the Cold War was driven by the ideological struggle between the capitalist United States and the communist Soviet Union. Throughout the world, the Soviet Union backed governments or insurgent groups willing to either adopt or ally themselves with communism, while the United States backed governments or insurgent groups willing to fight communism. The results in Central America were often highly destructive.
In 1954, the Guatemalan leader Jacobo Arbenz legalized the nation's communist party and attempted to seize lands owned by an American fruit company. The United States orchestrated his overthrow by Colonel Carlos Castillo Armas, leading to a civil war that began in 1960 and claimed more than 200,000 lives over the next 36 years.
After the Cuban dictator Batista was overthrown in 1959, US policy makers began to fear that Central America might also become communist. As Cuba's revolutionary leader Fidel Castro aligned himself more and more closely with the USSR, the US took steps to prevent communism from spreading to other nations in the region. This included multiple attempts to overthrow or assassinate Castro, as well as pressure on other nations in the region to keep Cuba diplomatically isolated. The US intervened either directly or indirectly in other Latin American nations such as Chile to prevent communism from expanding its foothold.
In Central America itself, Cuba and its Soviet allies supported the FMLN's communist insurgency in El Salvador through the 1980s, as well as the revolutionary government of the Sandinista movement in Nicaragua. The United States supported the right wing government of El Salvador in its efforts to defeat the communist insurgency while simultaneously supporting the Contra insurgency against the Nicaraguan government. The war in Nicaragua ended when the Sandinista government agreed to allow elections in 1990. The civil war in El Salvador lasted for 12 years before an end to the war was negotiated in 1992.
In all of these civil wars, government or insurgent forces backed by both sides were notorious for committing massacres and other war crimes. Hundreds of thousands of people were killed and society was destabilized to the extent that organized crime was allowed to flourish. Although the Cold War is over, the ideological hatred from that era is still a factor in Central American politics.
https://cja.org/where-we-work/el-salvador/

https://wcfia.harvard.edu/files/wcfia/files/jd_us_latin.pdf

https://www.pbs.org/newshour/health/latin_america-jan-june11-timeline_03-07