BRINGING FREEDOM and democracy to totalitarian Cuba will be no easy task. Two indispensable ingredients, though, must be courage on the part of the country’s dissidents and democrats, and international solidarity with them.

Both were on display in Havana over the past week. At the center of events was Rosa María Payá Acevedo, daughter of the late Oswaldo Payá, a recipient of the European Parliament’s Sakharov Prize for freedom of thought who lost his life in a still-unexplained 2012 car crash. Ms. Payá decided to pay tribute to her father by awarding a human rights prize in his name and chose as the first recipient Luis Almagro, the Uruguayan secretary general of the Organization of American States, who has distinguished himself through forthright condemnation of repression in Cuba’s authoritarian ally Venezuela. Ms. Payá invited former Mexican president Felipe Calderón, former Chilean education minister Mariana Aylwin (daughter of a former president) and Martin Palous, a former Czech ambassador to the United States, to attend.

Raúl Castro’s regime blocked them all from entering the country, telling Mr. Almagro that Ms. Payá’s entirely peaceful program was “anti-Cuban activity” and a “provocation.” Officials also detained journalists attempting to cover the planned ceremony, including Henry Constantin Ferreiro, regional vice chairman of the Inter American Press Association’s Committee on Freedom of the Press and Information. No doubt Ms. Payá’s unauthorized attempt to honor an international diplomat before such distinguished company did present the regime with an awkward choice: to tolerate an elementary exercise of her rights, and the rights of her invitees, or to deny it, and incur international political damage. How revealing of Havana’s true nature, and true priorities, that it chose the latter. Indeed, Cuba’s foreign ministry said the crackdown showed its determination not to “sacrifice its fundamental principles to maintain appearances.”

And how revealing of the limits of U.S. “engagement” with Cuba. While these European and Latin American leaders were supporting Ms. Payá’s assertion of freedom, a bipartisan delegation of six members of Congress, headed by Sen. Patrick Leahy (D-Vt.), were on a visit to Cuba, promoting business ties. After a visit with Mr. Castro, Mr. Leahy blandly observed that the dictator “wants reform to continue, he wants the movement forwards to continue” despite President Trump’s uncertain attitude toward the island’s government. Mr. Leahy’s spokesman told us that the delegation’s schedule was too “packed” with appointments such as the Castro meeting to allow for any contact with Ms. Payá, and declined to comment, pro or con, on the regime’s refusal to admit Mr. Almagro and company.

To be sure, Mr. Trump is hardly the ideal spokesman for democracy promotion, in Cuba or anywhere else. All the more reason that members of Congress supply on America’s behalf the solidarity Cuba’s democrats need, and all the more reason to be disappointed that Mr. Leahy and his colleagues did not provide more of it.