HAVANA — The political pretext for gathering scarcely registered, as 100,000 raucous young Cubans — packed densely into a historic square behind Havana University — clapped and jived to the salsa rhythm of legendary big band Los Van Van.

Teenage boys, many bused in from outside the capital, showed off facial piercings, tropical punk hairdos and Lycra muscle shirts as some chugged from flasks of cheap rum. The band's front man sported a fitted blue Yankees cap, while girls swayed with the music bellowing from massive speakers that dwarfed an undersized poster advertising the local communist youth group.

Officially, the reason for the concert held earlier this month was to celebrate the return of Fernando Gonzalez, the second of the “Cuban Five” to be released from prison in the U.S., after serving 15 years for espionage. Before the show ended, there was a perfunctory call for the liberation of the remaining three and mild cheers as the emcee denounced "U.S. imperialism" and "el bloqueo" — the U.S. economic embargo of its island neighbor, in force for the past 53 years without achieving its goal of bringing down communist rule.

The failure of the embargo to end the Castro regime — and the fact that Washington is internationally isolated in applying it — has prompted periodic debate in the U.S. about its value. Despite hope that Barack Obama's administration might ease the policy, any move to relax it draws significant domestic political opposition. Meanwhile, Cuba's regime is engaged in debates of its own, slowly making small policy changes that would have been unthinkable at the height of communist rule.

An economy in which the state was once the sole employer now includes a growing gray zone of private enterprises operating with the consent of the authorities. That reflects an effort by the communist leadership to stimulate an economy stunted by low growth, despite its relatively high human development index and bountiful government benefits. Only a small number of citizens have seen their living standards improve over the past two decades.

Some people in Cuba believe that an end to the U.S. embargo — long blamed by the leadership in Havana for all economic woes — would spur a much-needed boom. "Five million tourists could come from the U.S. to Cuba annually if the embargo were lifted," said Felipe Ventura, a chemical engineer from Havana. Despite the potential offered by its highly educated population, the Cuban economy's most dynamic sector remains tourism, which generates $2.6 billion annually. Although the embargo precludes conventional tourism from the U.S., Cuba welcomes a steady stream of visitors from Europe, Canada and Latin America.

He said that Cuban society takes good care of ordinary people, keeping down crime, drug abuse and homelessness, adding that Cuba's education and health care are “one to two generations ahead” of other Latin American nations such as Guatemala. Ventura, a Soviet-educated Ph.D., saw restrictive local laws on running private businesses as a far greater drag on economic growth than the U.S. embargo but still wants it lifted.

He spoke while dining at Rejoneo Asador in the capital's upscale Miramar neighborhood, an establishment that seems to illustrate his point. The restaurant, which serves mammoth portions of beef, is subject to a government rule limiting eateries to 50 chairs. So the owner created three dining areas — adjacent but technically separate — for a legal total of 150 seats. The venue includes a cafeteria called Tic-Tac W, whose symbol is an upside-down McDonald’s logo that represents two interlocking J's, for the co-owners' common first initial.