The State Department defended the visa decision on free-speech grounds. But that’s hard to square with its history of using visas as a policy tool. There are many examples of elected Latin American officials and military brass being refused travel to the U.S. for reasons that override their rights to express themselves. Two prominent examples come to mind. First, numerous members of the Colombian military—which is under civilian command—and in some cases members of their families, have had their U.S. visas pulled by the State Department merely because the soldiers were accused by left-wing nongovernmental organizations of human-rights violations. Even when acquitted, most never had those visas restored.

Then there was the visa-yanking by the Obama administration when it decided in 2009 that the Honduran Supreme Court was undemocratic because it had ruled that President Manuel Zelaya’s removal from power was constitutional. Team Obama also pulled the visas of members of the interim government, even though it took power in strict adherence to the constitution and with the backing of the major political parties, the Catholic Church and the country’s human-rights ombudsman. Those visas were not returned even when the interim government presided over a free and fair election and left power on schedule…

Ms. Castro did not travel in the U.S. like a private citizen. She was flacking for her old man and the State Department even gave her a security detail. A department official told me that she was entitled to that as a “child of a head of state.”