Castro

He tried firing squads, he tried sending academics into the sugar fields, he tried neighborhood snitches, he tried arresting journalists, he tried sending armies into Africa and South America to support Communism, he tried supporting Hugo Chavez/Maduro, he tried isolating his people from the outside world…but he failed.
His People revered him even in poverty, remembering that they were dirt poor under Batista, but the rich were really rich. The revolution didn’t make the poor any richer, but they loved seeing the rich made poorer. This is the eventual goal of Democratic Party wing under Sanders. 

Uniform poverty!

Now the liberals will tell you that the reason for Cuban poverty was the US embargo, but that claim can be dismissed easily: Canada had no embargo! Europe had no embargo, and those economic entities are hardly chopped liver!