Cuba has pledged to let 52 of its prisoners of conscience go. We hope their release happens, and soon. But there should be no illusions that this gesture augurs fundamental political change on the island that the Castro brothers, Fidel and Raúl, have ruled with an iron fist since 1959. The Castro regime has a long history of tactical human rights concessions -- with the goal of buying time for the regime rather than reforming it. This release would appear to fit the pattern.

Always impoverished and unfree, revolutionary Cuba is in extra-bad shape now. Cardinal Jaime Ortega, the usually discreet archbishop of Havana, recently warned of "a difficult situation" that calls for "quick" changes by the government lest "impatience and ill will" spread. The state-run economy is reeling: Tourism and mineral exports are down, foreign debt is up, and Venezuela is decreasingly able to help because of its own colossal mismanagement. Meanwhile, Cuba's dissidents are gaining in daring and prestige -domestically and internationally. The death of prisoner of conscience Orlando Zapata Tamayo after a 75-day hunger strike, as well as the attacks of government-backed mobs on peaceful demonstrations by wives and mothers of political prisoners, earned global condemnation and set back Spain's efforts to relax the European Union's policy linking economic aid with human rights progress. Dissident Guillermo Farinas is near death on a hunger strike of his own, demanding freedom for 25 political prisoners who are sick.

The regime could ill afford that embarrassment. So the promised release is a victory for Mr. Farinas. And it's no accident that it was coordinated with the Spanish government -or that it came a week after the House Agriculture Committee had approved lifting the ban on U.S. tourism to the island and easing U.S. food sales. Raúl Castro, who took over day-to-day control from his ailing brother four years ago, undoubtedly hopes to encourage these developments, which promise to relieve his cash crunch.

How should the United States respond? As suggested by the fact that cash-only food exports from the United States make this country Cuba's fifth-largest trading partner, "embargo" is already a misnomer to describe the main U.S. policy approach. In fact, along with Venezuelan petroleum and tourism, cash remittances from Cuban Americans, which President Obama already has eased, constitute one of Cuba's economic pillars. We don't generally approve of restrictions on where Americans may travel. But the Cuba "ban" already includes large exceptions for Cuban Americans, trade delegations and educational missions. Neither those visits nor the influx of Canadians and Europeans have had the effect of liberalizing the regime -though they have brought in hard currency.

The 52 inmates represent fewer than one-third of Cuba's 167 political prisoners, according to democracy advocate Freedom House. Among prisoners notably not mentioned for release on Wednesday was Alan Gross of Potomac, an Agency for International Development contractor imprisoned in Cuba since December for the crime of distributing cellphones and laptops in Cuba's tiny Jewish community. And the first five prisoners to be freed reportedly are going to be forced into exile as a condition of their release. Mr. Obama has wisely linked major changes in U.S. sanctions to significant movement toward democracy and freedom by Havana. That condition is still far from met.