One of the goals of the Trump administration’s pressure campaign against Cuba—including a comprehensive oil embargo, expanded U.S. Defense Department contingency planning , a U.S. indictment of former Cuban President Raúl Castro, and increasing calls on Capitol Hill for a military intervention—is to foment internal dissent that would lead to the toppling of the communist regime on the island. But the efforts have failed so far because emigration, Cuba’s most reliable release valve for dissent,