The largest party in Mexico is officially a socialist party and a member of the Socialist International. In Panama, since the US invasion, the government has been run by a party associated with Torrijos, a leftwing President murdered by the CIA. It alternates with an ostensibly rightwing populist party that has nevertheless put in many new social programs.
The Left in El Salvador and Nicaragua had to literally shoot their way into power at the cost of 155,000 dead. Costa Rica got rid of their army and put in a social democracy after World War 2 in part to ward off revolution. There was a military coup in Honduras a few years back which overthrew a Left president and put in a death squad government that has murdered 2,000 Leftists ever since.
Yes, the Right is in power in Guatemala, but they have stayed in power by killing 200,000 people, a project which is ongoing. The Left has now disarmed, but they were armed for over 30 years.