WASHINGTON — Senator John F. Kerry has spent much of his career sitting across from foreign leaders trying to find solutions to seemingly intractable problems — from Nicaragua to Pakistan and Vietnam to Syria.
If he becomes President Obama's next secretary of state as expected, Kerry will carry the greatest negotiating authority of his career — and face immense pressure to advance from an expert listener and seeker of common ground to an international dealmaker of the highest caliber.
Kerry has declined to give interviews in recent weeks as speculation about the pick has swirled around him. But he spoke to the Globe last summer about his decades of diplomatic experience in the context of his role as chairman of the Foreign Relations Committee.
"I've been doing this all of my life,'' said Kerry, sitting in a high-backed chair in the committee's formal US Capitol meeting room in June, in remarks that have previously not been published.
Many agree he is excellently positioned for the role of top American negotiator, with a global Rolodex matched by few others and a network of former staffers and diplomats spread across the world.
He played a prominent role in helping thaw relations with Communist Vietnam; cajoled a recalcitrant Nicaraguan dictator to seek peace; and is seeking ways to head off more bloodshed in Sudan, Afghanistan, Pakistan, and other unstable corners of the globe.
"He will be viewed as an appropriate representative of the United States with prime ministers, heads of state, and foreign ministers," said former senator Charles Robb, a fellow Vietnam veteran who is at the Bipartisan Policy Center. "He has become increasingly sure-footed in terms of how he approaches questions of foreign policy."
With the withdrawal of UN Ambassador Susan Rice from consideration, Kerry is considered the front-runner to replace Secretary of State Hillary Rodham Clinton in Obama's second term.
The Massachusetts Democrat's intermediary role dates back to the beginning of his Senate career in 1985, when he carried a letter from Nicaragua's Marxist leader Daniel Ortega to President Reagan pledging to seek a peace agreement with US-backed rebels.
"Some people were critical of it, but it was a genuine effort that sort of came about because I was engaged, and listening, and talking to people — meeting with them because I thought there was a different road you could take," Kerry recalled of his opening with Ortega, which was ultimately not pursued by Reagan.
A few years later, he and Senator John McCain sought answers on the whereabouts of missing US soldiers from the Vietnam War, which was a seminal event in both men's lives.
Such efforts demonstrate Kerry's belief in the need to engage friends and enemies to advance American interests — even if it means sitting down with those who hold distasteful viewpoints.
"I negotiated with the president of Vietnam, with the chief of the Communist Party, with all of these different people because we had to try to keep the process moving," Kerry told the Globe in the wide-ranging interview in June.
In more recent years Kerry has been a chief surrogate for the Obama administration.
In 2009, during a series of marathon tea drinking sessions, he persuaded President Hamid Karzai of Afghanistan to agree to a runoff election after he prematurely declared victory in flawed balloting. Until meeting with Kerry, Karzai had refused to meet with any US official about the vote.
"He did not take credit for his efforts in US media, which convinced Afghans of his sincerity," recalled Husain Haqqani, the former Pakistani ambassador, who said Kerry's similar personal relationships in his country "have proved useful in defusing crises behind the scenes."
Last year, as mob violence roiled in the streets outside, Kerry was one of the first US officials to appeal directly to Egypt's Muslim Brotherhood — including current President Mohammed Morsi — to maintain the country's peace treaty with Israel and adopt democratic reforms.
But his successes have been spiked with disappointments.
In Syria, for example, his belief that President Bashir Assad could be an agent of positive change in the Middle East — based on several personal meetings with him in Damascus — has been proved to be wholly misguided.
Unlike for popular uprisings in Egypt and Libya, Kerry was uncharacteristically silent in the early days of Assad's ruthless crackdown on opposition forces.
Some who have seen Kerry operate up close detect flaws in his negotiating approach.
"He gets so wrapped up in wanting to have a deal that he tends to lose sight of whether the deal is worth making," said one former official with experience in negotiations with foreign leaders. "He doesn't know when to walk away. His view is any deal is better than no deal."
The former official, who did not want to be quoted for fear of harming his career, credited the senator's seemingly inhuman ability to sit patiently for hours listening to foreign officials drone on.
"Part of being a good diplomat is having an iron butt. Sitting in the room and listening to a lot of [expletive]," the former official said. "But are you doing that to get a desired result or walking away with nothing?"
Many in both parties, however, say any missteps on the global stage are the exception.
"What's impressive is he goes into any negotiation very well prepared," said Timothy Wirth, a former Democratic senator from Colorado and undersecretary of state. "He knows where he wants to go. He wants to drive you to those points. He is a very tested envoy, both publicly and privately."
Kerry also knows the nuts and bolts of statecraft, they say. He has shepherded arms control and other treaties through the Senate and overseen passage of annual legislation to authorize the State Department budget.
"John has been preparing for this role for much of his public life," said William S. Cohen, formerly a secretary of defense and Republican senator from Maine. "He conducts himself with great skill."
Martin Indyk, who twice served as US ambassador to Israel, said Kerry's personal relationships with diverse leaders ranging from Prime Minister Benjamin Netanyahu of Israel to Egypt's newly elected Morsi should help him achieve US goals.
"These leaders have to make life-death decisions, both for themselves and their people," said Indyk. "They trust him."
Added Haqqani, who traveled with Kerry to see devastating flood damage in Pakistan in 2010: "Senator Kerry's greatest strength is his understanding that the world is complex and the success of diplomacy depends not on telling others what to do but on finding what works for both sides."