Alan Gross: The key to a US-Cuba thaw
It's been exactly five years since the US government contractor Alan Gross was arrested in Havana, dashing hopes amongst anti-embargo advocates that President Barack Obama would make a bold move on Cuba policy.
But a forthcoming regional summit has focused attention on whether Mr Obama will use his remaining two years in office to normalise relations with Cuba, and a resolution of Mr Gross's case would be a key part of that.
The American prisoner has himself raised the stakes. When he turned 65 in May he told his family he refused to spend another birthday in prison, suggesting he would kill himself if he isn't released.
Alan Gross was jailed for 15 years for committing "acts against the integrity of the state".
He'd been working to build internet access for local communities that bypassed government censorship, bringing in satellite equipment that is illegal in Cuba.
Washington maintains the project was aimed at promoting democracy and Mr Gross committed no crime. But the Cuban authorities saw his activities as a covert attempt at regime change.
At that point Mr Obama had rolled back the hardline approach to Cuba taken by his predecessor, George W Bush.
He had reinstated cultural and academic exchanges, allowed Cuban-Americans to travel to Cuba and send money to their relatives, and opened talks on issues of mutual interest.
But he has taken no steps towards easing America's trade and financial sanctions on the island. It's not clear if he would have done so, but Mr Gross's case ensured that he did not.
Now though, Mr Obama is expected to meet the Cuban President Raul Castro at the seventh Summit of the Americas in Panama in April.
Latin American countries insisted that Cuba no longer be excluded, setting the scene for "the most extraordinary moment in Cuban/American relations in recent history," says Peter Kornbluh, co-author of the recently published Back Channel to Cuba.
Political shifts in the United States have indeed made fundamental change feasible.
Washington began imposing sanctions on Cuba in 1961 with the aim of ousting the socialist regime of Fidel Castro. Although the policy has failed, any attempt to change it has been resisted by an influential block of Cuban-American voters concentrated in Florida.
But the virulently anti-Castro generation in Miami is aging and polls show that younger Cuban-Americans and recent immigrants are more open to engagement.
Mid-term elections in November that handed Republicans control of the Senate may also have given the administration some room to manoeuvre. The Democratic senator and Cuba hawk heading the Senate Foreign Relations Committee, Robert Menendez, has lost his position, which he would have used to oppose any openings to the Castros.
Meanwhile in Cuba, Fidel Castro quietly retired in 2006 and economic pressures forced his brother Raul to institute reforms that have begun to liberalise the state-controlled economy.
Raul Castro also released more than 100 political prisoners in 2010 and last year lifted restrictions on Cubans travelling abroad.
The pace and scope of the economic reforms have been criticised, and despite slightly better access to the internet there's still "no free press or big change in freedom of expression and association" in the one-party state, a Western diplomat in Havana says.
But anti-embargo advocates and even some dissidents say lifting the American economic sanctions could help open up political space, arguing that the Cuban government uses US policy as an excuse to justify repression.
Rafael Hernandez, the editor of the Cuban social science journal Temas, says the government has good reason to see the US as a threat, but "for the vast majority of Cubans those [US] changes could facilitate reforms."
"The question of a foreign power that openly aims to undermine the political system in Cuba has been for the last 55 years a domestic factor, it is part of us," he told the BBC.
But "if we don't have to think so much about the US as a threat, that would facilitate a public debate that is not framed within the national security mentality".
Editorial push: Thomas Sparrow, BBC Mundo
Cuba clearly is on the minds of the editors of the New York Times.
In the last month the paper has published six weekend editorials in English and in Spanish asking the US administration to re-establish diplomatic ties with Cuba.
Andrew Rosenthal, the New York Times's editorial page editor, told the BBC that the six editorials have been in line with the newspaper's longstanding position on Cuba and the embargo.
Nevertheless, it is intriguing that the Times has been running so many consecutive pieces on the same country, with clearly defined intervals, in two languages and in moments when President Barack Obama is defining his agenda for his remaining two years in office.
The motivation behind the paper's month-long crusade is that the editors believe that "for the first time in more than 50 years", the situation both in Cuba and the US favours such deep political change.
While there is less resistance to change US policy now, there is no real incentive for an administration busy with a host of foreign crises.
"When it comes to Cuba, there's no consequence for supporting the status quo," says Representative Jim McGovern, an anti-embargo campaigner, "so the challenge is to find a way to build political pressure."
If the administration does decide to change the status quo, a prisoner swap might be the place to begin.
The Cuban government has long pushed for the release of five convicted Cuban spies imprisoned in the US - two were recently allowed to return to Cuba after finishing their sentences.
So far Washington has refused to exchange the remaining three for Alan Gross, insisting the cases are not equivalent. But such a step would make it easier to move towards a resumption of diplomatic relations.
"This would be the most important gesture the US could make to start normalising relations," says Mariela Castro, a Cuban Member of Parliament and the daughter of Raul Castro.
"And it's in the capacity of President Obama to take this decision," she told the BBC in an interview. "If Alan Gross is still in Cuba it's because Obama hasn't taken the necessary step to give our three comrades back. If he did, Gross would immediately return to America."
Besides restoring diplomatic relations, President Obama could remove Cuba from the State Department's list of countries that sponsor terrorist organisations, since it no longer does. The designation along with Sudan, Iran and Syria is a source of some of the most crippling financial sanctions.
And he could significantly ease the effects of the economic embargo, although he doesn't have the authority to lift it - only Congress could do that.
Whatever the case, Cuba experts have their eye on the next five months, which they've branded a diplomatic window of opportunity.