In the past week, the two countries have held talks on resuming direct mail service, and announced a July 17 sit-down on migration issues. In May, a U.S. federal judge allowed a convicted Cuban intelligence agent to return to the island. This month, Cuba informed the family of jailed U.S. government subcontractor Alan Gross that it would let an American doctor examine him, though the visit has apparently not yet happened. Castro has also ushered in a series of economic and social changes, including making it easier for Cubans to travel off the island.
Under the radar, diplomats on both sides describe a sea change in the tone of their dealings.
Only last year, Cuban state television was broadcasting grainy footage of American diplomats meeting with dissidents on Havana streets and publically accusing them of being CIA front-men. Today, U.S. diplomats in Havana and Cuban Foreign Ministry officials have easy contact, even sharing home phone numbers.
Josefina Vidal, Cuba's top diplomat for North American affairs, recently traveled to Washington and met twice with State Department officials — a visit that came right before the announcements of resumptions in the two sets of bilateral talks that had been suspended for more than two years. Washington has also granted visas to prominent Cuban officials, including the daughter of Cuba's president.
"These recent steps indicate a desire on both sides to try to move forward, but also a recognition on both sides of just how difficult it is to make real progress," said Robert Pastor, a professor of international relations at American University and former national security adviser on Latin America during the Carter administration. "These are tiny, incremental gains, and the prospects of going backwards are equally high."
Among the things that have changed, John Kerry has taken over as U.S. secretary of state after being an outspoken critic of Washington's policy on Cuba while in the Senate. President Barack Obama no longer has re-election concerns while dealing with the Cuban-American electorate in Florida, where there are also indications of a warming attitude to negotiating with Cuba.
Cuban President Raul Castro, meanwhile, is striving to overhaul the island's Marxist economy with a dose of limited free-market capitalism and may feel a need for more open relations with the U.S. While direct American investment is still barred on the island, a rise in visits and money transfers by Cuban-Americans since Obama relaxed restrictions has been a boon for Cuba's cash-starved economy. Under the table, Cuban-Americans are also helping relatives on the island start private businesses and refurbish homes bought under Castro's limited free-market reforms.
Several prominent Cuban dissidents have been allowed to travel recently due to Castro's changes. The trips have been applauded by Washington, and also may have lessened Havana's worries about the threat posed by dissidents.
Likewise, a U.S. federal judge's decision to allow Cuban spy Rene Gonzalez to return home was met with only muted criticism inside the United States, perhaps emboldening U.S. diplomats to seek further openings with Cuba.
To be sure, there is still far more that separates the long-time antagonists than unites them.
The State Department has kept Cuba on a list of state sponsors of terrorism and another that calls into question Havana's commitment to fighting human trafficking. The Obama administration continues to demand democratic change on an island ruled for more than a half century by Castro and his brother Fidel.
For its part, Cuba continues to denounce Washington's 51-year-old economic embargo.
And then there is Gross, the 64-year-old Maryland native who was arrested in 2009 and is serving a 15-year jail sentence for bringing communications equipment to the island illegally. His case has scuttled efforts at engagement in the past, and could do so again, U.S. officials say privately. Cuba has indicated it wants to trade Gross for four Cuban agents serving long jail terms in the United States, something Washington has said it won't consider.
Ted Henken, a professor of Latin American studies at Baruch College in New York who helped organize a recent U.S. tour by Cuban dissident blogger Yoani Sanchez, said the Obama administration is too concerned with upsetting Cuban-American politicians and has missed opportunities to engage with Cuba at a crucial time in its history.
"I think that a lot more would have to happen for this to amount to momentum leading to any kind of major diplomatic breakthrough," he said. "Obama should be bolder and more audacious."
Even these limited moves have sparked fierce criticism by those long opposed to engagement. Cuban-American congressman Mario Diaz Balart, a Florida Republican, called the recent overtures "disturbing."
"Rather than attempting to legitimize the Cuban people's oppressors, the administration should demand that the regime stop harboring fugitives from U.S. justice, release all political prisoners and American humanitarian aid worker Alan Gross, end the brutal, escalating repression against the Cuban people, and respect basic human rights," he said.
Another Cuban-American politician from Florida, Rep. Ileana Ros-Lehtinen, scolded Obama for seeking "dialogue with the dictatorship."
Despite that rhetoric, many experts think Obama would face less political fallout at home if he chose engagement because younger Cuban-Americans seem more open to improved ties than those who fled immediately after the 1959 revolution.
Of 10 Cuban-Americans interview by The Associated Press on Thursday at the popular Miami restaurant Versailles, a de facto headquarters of the exile community, only two said they were opposed to the U.S. holding migration talks. Several said they hoped for much more movement.
Jose Gonzalez, 55, a shipping industry supervisor who was born in Cuba and came to the U.S. at age 12, said he now favors an end to the embargo and the resumption of formal diplomatic ties. "There was a reason that existed but it doesn't anymore," he said.
Santiago Portal, a 65-year-old engineer who moved to the U.S. 45 years ago, said more dialogue would be good. "The more exchange of all types the closer Cuba will be to democracy," he said.
Those opinions dovetail with a 2011 poll by Florida International University of 648 randomly selected Cuban-Americans in Miami-Dade County that said 58 percent favored re-establishing diplomatic relations with Cuba. That was a considerable increase from a survey in 1993, when 80 percent of people polled said they did not support trade or diplomatic relations with Cuba.
"In general, there is an open attitude, certainly toward re-establishing diplomatic relations," said Jorge Duany, director of the Cuban Research Institute at Florida International University. "Short of perhaps lifting the embargo ... there seems to be increasing support for some sort of understanding with the Cuban government."