The Left has run Cuba since 1959. Most of the illegal opposition groups in Cuba are formally socialist (social democratic) The Left is only kept out of power in Haiti because the rightwing army and police have all the guns and the Left is not allowed to run in the fake elections. The Left president Aristide was overthrown in a violent, US sponsored coup. Jamaica elected a socialist in the 1970’s, Manley. His government was undermined by the US, and he was thrown out after a bit.
The Left held power in Grenada but was overthrown by a US invasion. Dominica is formally ruled by a socialist party which is also a member of the Sao Paolo Forum. The opposition is a party with “workers” in its name. Grenada has recently been ruled by a party that is a member of the Progressive Alliance, a split from the Socialist International. Trinidad and Tobago is now run by a formally socialist party. The two principal opposition parties are both formally socialist parties.
The Right stayed in power in the Dominican Republic by a dictator named Trujillo killing hundreds of thousands of people. In the 1960’s, they elected a socialist, Juan Bosch, who was quickly overthrown by Johnson with a CIA coup. The new rightwing government came in via the coup and stayed in power for over a decade. They stayed in power by murdering 11,000 people. For the last 20 years, the country has been ruled by the formally socialist party of Bosch. They are aligned with the Far Left Sao Paolo Forum. The opposition party has “revolution” in its name, is formally socialist and is a member of the Socialist International.