WASHINGTON/MIAMI - The December breakthrough that upended a half-century of US-Cuba enmity has been portrayed as the fruit of 18 months of secret diplomacy.
But Reuters interviews with more than a dozen people with direct knowledge of the process reveal a longer, painstakingly cautious quest by US President Barack Obama and veteran Cuba specialists to forge the historic rapprochement.
As now-overt US-Cuban negotiations continue this month, Reuters also has uncovered new details of how talks began and how they stalled in late 2013 during secret sessions in Canada. Senior administration officials and others also revealed how both countries sidelined their foreign policy bureaucracies and how Obama sought the Vatican's blessing to pacify opponents.
Obama's opening to Havana could help restore Washington's influence in Latin America and give him a much-needed foreign policy success.
But the stop-and-start way the outreach unfolded, with deep mistrust on both sides, illustrates the obstacles Washington and Havana face to achieving a lasting detente.
Obama was not the first Democratic president to reach out to Cuba, but his attempt took advantage of - and carefully judged - a generational shift among Cuban-Americans that greatly reduced the political risks.
In a May 2008 speech to the conservative Cuban-American National Foundation in Miami, Obama set out a new policy allowing greater travel and remittances to Cuba for Cuban-Americans, though he added he would keep the embargo in place as leverage.
"Obama understood that the policy changes he was proposing in 2008 were popular in the Cuban-American community so he was not taking a real electoral risk," said Dan Restrepo, then Obama's top Latin America adviser.
Six months later, Obama was validated by an unexpectedly high 35 per cent of the Cuban-American vote, and in 2012 he won 48 per cent - a record for a Democrat.
With his final election over, Obama instructed aides in December 2012 to make Cuba a priority and "see how far we could push the envelope," recalled Ben Rhodes, a Deputy National Security Advisor who has played a central role in shaping Cuba policy.
Helping pave the way was an early 2013 visit to Miami by Obama's top Latin American adviser Ricardo Zuniga. As a young specialist at the State Department he had contributed to a 2001 National Intelligence Estimate that, according to another former senior official who worked on it, marked the first such internal assessment that the economic embargo of Cuba had failed.
He met a representative of the anti-Castro Cuban American National Foundation, and young Cuban-Americans who, according to one person present, helped confirm the waning influence of older Cuban exiles who have traditionally supported the half-century-old embargo.
But the White House wasn't certain. "I don't think we ever reached a point where we thought we wouldn't have to worry about the reaction in Miami," a senior US official said.
The White House quietly proposed back-channel talks to the Cubans in April 2013, after getting notice that Havana would be receptive, senior US officials said.
Obama at first froze out the State Department in part due to concern that "vested interests" there were bent on perpetuating a confrontational approach, said a former senior US official. Secretary of State John Kerry was informed of the talks only after it appeared they might be fruitful, officials said.
Cuban President Raul Castro operated secretly too. Josefina Vidal, head of US affairs at Cuba's foreign ministry, was cut out, two Americans close to the process said. Vidal could not be reached for comment.
The meetings began in June 2013 with familiar Cuban harangues about the embargo and other perceived wrongs. Rhodes used his relative youth to volley back.
"Part of the point was 'Look I wasn't even born when this policy was put in place … We want to hear and talk about the future'," said Rhodes, 37.