While Congress is considering Congressman Rangel’s bill to eliminate the American embargo against Cuba, meet Alberto Justo Rodríguez. Mr. Rodríguez is a Cuban who, along with about 100 of his countrymen, was sent by his government to work in a dry dock in Curacao. When they arrived, their passports were seized, and they were closely guarded by Cuban officials, including one of Mr. Castro’s nephews.

Mr. Rodríguez and his companions were forced to work 16-hour days in dangerous conditions — hanging from the sides of ships and scraping rust or huddling in wet spaces while working with high voltage equipment. Injured workers received no compensation, and on free days — which were few — the Cubans had to watch videos of Mr. Castro’s long, rambling speeches. The Cubans received the equivalent of $16 a month —between 3 and 4 cents an hour. The real value of their labor was paid to the Cuba’s communist regime by the Curacao dry dock in hard currency.

Mr. Rodríguez and two of his coworkers later escaped to America, and last year they filed suit against the dry dock in an American court under the Alien Torts Statute. It’s an important lawsuit because the case of the Cuban dry dock slaves is not an isolated one. Resorting to supplying slave labor in exchange for hard currency is a well-documented strategy of the perpetually cash-strapped Cuban government. The Cuban doctors who travel the world doing cataract surgery get paid a pittance, while their masters in the Cuban government pocket dollars.

More cynically still, European companies set up factories in Cuba with the same arrangement. The entire Cuban tourism industry is designed to provide luxury service to foreigners in exchange for hard currency, while the Cubans that work in the industry earn slave wages. Mr. Rangel knows about all this. He’s stayed in Cuba’s luxury hotels multiple times at the invitation of Mr. Castro, and he has been served by the Cubans forced to work at those hotels for what amounts to slave wages.

If, as Mr. Rangel is proposing, Congress were to allow American citizens to spend their dollars in this system of oppression, it might be great for American business. Yet in the years since the Soviet Union collapsed and Cuba began trading with the rest of the world, the Castro regime has not only remained, but has grown stronger as it developed this system in its scramble for hard currency. Dropping the American trade embargo would perpetuate a kind of slavery that is typical of the communist system and that has no place in the civilized world.