WASHINGTON — With a patrician bearing, nearly three decades of service on the Senate Foreign Relations Committee, a highly decorated combat career in the Vietnam War, even a father who was a diplomat, John Kerry is the very picture of a secretary of state.
“In a sense, John’s entire life has prepared him for this role,” President Obama said on Friday at the White House, as he nominated Mr. Kerry to replace Hillary Rodham Clinton, the first step in filling out a national security team for his second term.
Mr. Obama praised Mr. Kerry, 69, a Massachusetts Democrat, for having been immersed in “every major foreign-policy debate for nearly 30 years.”
But though Mr. Kerry would bring even deeper experience to the job than Mrs. Clinton did, his appointment is likely to further centralize policy decisions in the White House, where for the past four years the president and a small circle of advisers have kept a tight grip on issues like Iran’s nuclear program, China, Pakistan, and the winding down of the war in Afghanistan.
“There’s every reason to believe that we’re going to have a very White House-centric foreign policy,” said David J. Rothkopf, the chief executive of the Foreign Policy Group. “Kerry is going to have to show his loyalty and willingness to work within the Obama system.”
In contrast to Mrs. Clinton, whom Mr. Obama named to his cabinet after they competed against each other in the 2008 presidential primaries, Mr. Kerry has been a loyal supporter of the Obama administration, guiding an arms-reduction treaty with Russia to ratification in the Senate and playing diplomatic troubleshooter for the White House in Afghanistan, Pakistan and Sudan.
He has also figured at critical moments in Mr. Obama’s career. At the 2004 Democratic National Convention that nominated him for president, Mr. Kerry gave the keynote speaking slot to Mr. Obama, then a little-known Illinois state senator, catapulting him to national prominence. In early 2008, Mr. Kerry endorsed him over Mrs. Clinton, and this fall he played the role of Mitt Romney in mock debates — sessions that by some accounts put the president’s teeth on edge.
“Nothing brings two people closer together than weeks of debate prep,” said Mr. Obama on Friday, looking at a grinning Mr. Kerry. “John, I’m looking forward to working with you instead of debating you.”
However lavish Mr. Obama’s praise, his instinctive choice for secretary of state was Susan E. Rice, the ambassador to the United Nations, who withdrew her name from consideration after Republicans threatened to block her nomination because of statements she made after the lethal attack on the American Mission in Benghazi, Libya.
Mr. Obama, his aides said, likes Ms. Rice’s blunt style and is in sync with her view of foreign policy, which places a premium on aggressively defending human rights.
As a result, Ms. Rice, who is staying in her post, remains a candidate for a major foreign-policy post in the second term, according to administration officials. Thomas E. Donilon, the national security adviser, is expected to stay on for a year or so, but Ms. Rice could be named to his job.
If she were to move into the White House, analysts said, that would pose a test for Mr. Kerry, given her access to Mr. Obama and their shared views on many foreign policy issues.
“The easiest model to see developing is one in which Kerry is on the road a lot, interfacing with foreign leaders, but the decision-making is done at the White House,” said Elliott Abrams, who held foreign-policy posts in the administrations of Ronald Reagan and George W. Bush.
Mr. Obama expressed confidence that Mr. Kerry would be confirmed by his Senate colleagues, a prediction that seemed safe, given that at a recent news conference, Senator John McCain, Republican of Arizona, one of Ms. Rice’s fiercest critics, jokingly referred to Mr. Kerry as “Mr. Secretary.”
Mrs. Clinton has not announced her resignation, but she has made it clear she would not stay beyond a single term. Because she is recovering from a concussion, she did not appear at the midday announcement. Mr. Obama said that he spoke to her on Friday morning, and reported that she was “in good spirits.”
In a statement, Mrs. Clinton said Mr. Kerry was a leader of the “highest caliber,” who had advocated on behalf of diplomacy and development in Congress.
Mr. Kerry is working with her to adopt the recommendations of a recent report that harshly criticized the State Department for lapses in security in Benghazi, she said. The Benghazi attack, analysts said, underscored the management challenge for a longtime senator like Mr. Kerry in taking over a sprawling worldwide bureaucracy. Former aides to Mr. Kerry point out that he did oversee a huge, if temporary, campaign operation in 2004, which, though criticized for tactical missteps, was not viewed as poorly managed.
Although Mr. Kerry is not a global celebrity like Mrs. Clinton, his background as a presidential nominee and his chairmanship of the Foreign Relations Committee have made him well known abroad, accustomed to meeting monarchs and presidents.
In October 2009, he was viewed as instrumental in persuading President Hamid Karzai of Afghanistan to accept the need for a runoff election. Mr. Kerry spent 20 hours over five days with Mr. Karzai, telling him over dinner and in long walks in the garden of the presidential palace in Kabul of his own frustrations at the ballot box in 2004.
“I told him, ‘Sometimes there are tough things,’ ” Mr. Kerry said in an interview at the time.
Before Syria exploded in violence, Mr. Kerry met several times with its president, Bashar al-Assad, hoping to draw him into a more constructive role in the Middle East. His failed effort at engagement may elicit some tough questions from Mr. McCain and other Senate hawks.
As a senator, Mr. Kerry compiled a strong record on climate change, and environmental groups issued enthusiastic responses to his nomination. But Mr. Obama, pressed at a recent news conference, said climate change would take a back seat to the economy, at least for now.
For Mr. Kerry, exerting influence internally is likely to be the greatest challenge of the job he has long coveted. Friends and former aides predicted he would carve out a role, just as Mrs. Clinton did.
“John was someone who from an early age dreamed of being president,” said Jim Gomes, a former chief of staff to Mr. Kerry. “As someone who grew up in a Foreign Service family, who testified before Senate Foreign Relations after coming home from Vietnam and who wanted to serve on Foreign Relations, this is a pretty terrific Plan B.”