The World Court ruled against the US for its military aggression against Nicaragua in the 80s when it organized and armed the Contras.
Human rights groups documented that the US’s Contra war was militarily ineffective but did kill many unarmed civilians.
Several Reagan officials were convicted in the US of crimes in connection with the Contras. One of them now leads the NRA.
In the 1980s, Guatemala launched a genocide which killed tens of thousands of indigenous Mayans to prevent them from joining an insurgency against the dictatorship. Reagan administration tried to support that government. El Salvador’s military also killed tens of thousands of civilians, while getting heavy US financial and military support. Opposition press was murdered by govt-affiliated death squads.
The leftist Sandinista government of Nicaragua harassed opposition politicians and press and committed human rights abuses, but nothing like the magnitude of US’S Central American allies. The Latin American Studies Association reported on the 1984 election as did the general counsel from the New York Civil Rights Commission.
When the Sandinistas lost an election, they relinquished the presidency to the opposition, like other democracies.
Oh by the way the US killed Guatemalan democracy in 1954 by organizing a coup against the elected government.