After taking office last year with high hopes of delivering fresh US policies, Obama promised a "new beginning" in half a century of US-Cuban Cold War enmity and slightly eased the longstanding US embargo against the cash-strapped Caribbean island still led by the aging Castro brothers.
But expected further relaxations stalled and may now go back into deep freeze after wins by Republicans in Tuesday's midterm elections handed them control of the House of Representatives and boosted them in the Senate. It also put one of the most vocal anti-Castro foes in the United States in line to head the influential House Foreign Affairs Committee.
Florida's Ileana Ros-Lehtinen, a Cuban-American whose unrelenting castigation of the Castros has earned her the title of "ferocious she-wolf" in Cuban state media, is poised to take the committee chair, as the ranking Republican. She firmly opposes any rapprochement with communist-led Cuba.
Congress' Cuban exile contingent was also reinvigorated by the election as Florida Senator of Tea Party star Marco Rubio, 39, a Miami-born son of Cuban immigrants, who made a point of emphasizing his Cuban exile roots in his victory speech.
Advocates of widening contacts and trade with Cuba see Ros-Lehtinen as a potential major obstacle to any initiatives to lift travel restrictions on Americans visiting the island.
"The pro-sanctions forces have clearly been strengthened by the results of the election," said Sarah Stephens, executive director of the Center for Democracy in the Americas.
She and other analysts said this expected congressional deadlock put the onus on President Obama himself to take the lead in advancing his vision - enunciated at a Summit of the Americas last year - of a reformed relationship with Cuba, and of a more active partnership with Latin America as a whole.
Obama, who cannot lift the entangled Cuba embargo legislation without Congress but can use his executive authority to relax parts of it, has been careful to link improved ties with a call for Havana to free political prisoners and improve human rights.
Some observers argue the opportunity now exists after President Raul Castro, facing intense international pressure, struck a deal this year with the Catholic Church on the release into exile of more than 50 political prisoners.
While vowing no shift to capitalism on his watch, Castro is also introducing reforms of Cuba's socialist economy that allow more private sector activities in a bid to boost productivity.
"Clearly, there are changes going on in Cuba ... it means that if the president wants to stick with his own policy, and if he wants to have influence in Cuba, this would be a good time to make a reciprocal gesture," said Phil Peters, a Cuba expert at the Lexington Institute in Arlington, Virginia.
Peters said the Obama administration had before the elections prepared new rules to liberalize US-Cuban "nontourist travel," a modest easing of the embargo favoring cultural, sporting, academic and religious trip contacts.
But the White House had not implemented the rules "because of political timidity," Peters said.
"It comes down to the administration's spine," he added.
US officials have cited Cuba's detention since December of a US contractor as a major block to improving relations. Havana says Alan Gross is suspected of espionage and subversion, a charge rejected by Washington.
A more significant initiative in Congress to abolish the decades-old ban on travel by Americans to Cuba stalled in September when the then Democrat-led House Foreign Affairs Committee postponed a vote on the measure.
Some supporters of change hope outgoing Chairman Howard Berman might still advance the bill in a "lame duck" session before Republicans assume control of the House in January.
But Cuba watchers recognize the main focus of US leaders and the American public at the moment is on the economy.
"Foreign policy isn't going to be a focus of this Congress, much less Latin America, much less Cuba," Peters said.
Nevertheless, Ros-Lehtinen is expected to take her visceral opposition to Castros in Cuba to her new role as the House Foreign Affairs Committee chair, and new Florida Sen. Rubio emotively evoked "the story of the Cuban exile community" after his resounding election win late on Tuesday.
In an interview before the election, Rubio made clear he supported the embargo as "leverage" to achieve democratic change in Cuba. He also opposed lifting travel restrictions.
With some already viewing him as a potential Republican presidential contender in 2012, this sets up the intriguing historical possibility of a Cuban-American US president - food for thought for the long-lasting Castros in Cuba.
