Obama, who was in the first steps of what would become a strategic courtship, called afterward to thank her. By then, close aides to Clinton said, she had come to respect the campaign Obama had run against her. At the least, she knew he understood like no one else the brutal strains of their epic primary battle.

By this past Thursday, when Obama reassured Clinton that she would have direct access to him and could select her own staff as secretary of state, the wooing was complete.

"She feels like she's been treated very well in the way she's been asked," said a close associate of Clinton, who like others interviewed asked for anonymity because the nomination will not be formally announced until after Thanksgiving.

Few are predicting that this new relationship born of mutual respect and self-interest will grow into a tight bond between the new president and the woman who will be the public face of his foreign policy around the world, though some say it is not impossible. They argue that a close friendship between those in those powerful roles is useful but not essential, and is not a predictor of the success of the nation's chief diplomat.

While James Baker III was extraordinarily close to the first President George W. Bush and is widely considered one of the most successful recent secretaries of state, Dean Acheson was not a friend of President Harry Truman and Henry Kissinger did not particularly like Richard Nixon.

"Two of the nation's greatest secretaries of state in the modern period, Dean Acheson and Henry Kissinger, were not personally close but were intellectually bonded to their presidents," said Walter Isaacson, the author of a biography of Kissinger and of the book "The Wise Men," a history of America's postwar foreign policy establishment. "I think that Obama and Clinton could form a perfect partnership based on respect for each other's view of the world."

Colin Powell, President Bush's first-term celebrity secretary of state, would appear to be a cautionary tale for Clinton since his relationship with the president was strained, and he left office an unhappy man. But Condoleezza Rice, Bush's second-term secretary of state, is generally not viewed as having the success her unusually tight bond with the president might have engendered.

In the Obama-Clinton relationship, advisers say, the relatively smooth nature of their talks about the secretary of state job indicate that both, for now, have a working chemistry. The advisers say that Obama was clearly interested in bringing a rival under his wing, and that he also recognized that Clinton had far more discipline and focus than her husband.

At the same time, Obama's advisers said, he had the self-confidence to name a global brand as his emissary to the world. He recognizes, they said, that after Jan. 20, he will have to build the kind of relationship that ensures that foreign leaders know that when Clinton speaks, she is speaking directly for him.

"It helps to have a relationship that Bush had with Baker, that's no doubt true," said Martin Indyk, the former American ambassador to Israel, who was a supporter of Clinton in the primary battles. "But if they are seen as working together effectively, I think that can be easily overcome. I don't think he would have decided to appoint her if he didn't want her to be effective."

One close adviser to Obama said the president-elect also saw that Clinton's political skills would serve her well in the job, as happened with Baker and Kissinger. They understood that statecraft is politics by another name, the adviser said.

Obama and Clinton first spoke after their primary fight on a flight in June to Unity, New Hampshire, their first stage-managed appearance after Obama won the nomination. As they settled into their seats on Obama's plane, the conversation, according to people on both sides, was far less awkward than they had feared. Over the passing weeks, the relationship gradually improved.

"They got past this long before their supporters and the party activists did," said one Democrat who is close to both senators.

After Clinton's speech in support of Obama at the Democratic convention, she crisscrossed the country tirelessly to campaign for him — so much so that Obama told aides he was impressed by the sheer number of events Clinton was doing on his behalf.

Clinton, it should be said, was herself diligent in advertising how hard she was working for the man who defeated her. When announcing her appearances, her press office included tallies of how many events she had held for Obama, and in how many states. At some rallies, organizers would distribute "Hillary Sent Me" buttons, as if Clinton was being magnanimous by "sending" her followers to vote for Obama.

But Obama began calling Clinton after some of the events — he dialed directly from his cellphone to hers one day in Michigan and another day in Florida — to check in and thank her for helping. By then, their intense primary fights over policy, which both sides now insist was more about heat than substance, had long receded.

"The reality at the end of the day was, whether it was Iran or health care or some of these other issues, we were always fighting big battles over small differences," said a senior aide to Obama, adding that "in a campaign, conflict is what you go to."

Substantively, the two were at odds over the Iraq war — Clinton voted to authorize it and Obama said he would have opposed it had he been in the Senate then — and to a lesser extent over negotiations with Iran. But although Clinton criticized Obama for being willing to sit down and talk to dictators, Obama has said he would have a lower-level envoy do preparatory work for a meeting with Iran's leaders first. Clinton has said she favors robust diplomacy with Iran and lower-level contacts as well.

In the weeks just before the election, the relationship between Obama and Clinton further mellowed, even as Clinton found herself in a startling role reversal with her younger rival. As a celebrity senator and powerhouse on Capitol Hill, she had helped Obama in his Senate race and offered advice when he first came to Washington; now she was the workhorse for a political phenomenon.

Since the election, Clinton has talked to Obama only a handful of times, even as two close advisers to Obama who held top positions in the Clinton administration — Rahm Emanuel and John Podesta — have served as key negotiators between her and the president-elect on the secretary of state position.

But Clinton has talked several times to Michelle Obama about raising a family in the White House and private schools in Washington. On Friday, Obama said the two Obama girls would attend the Sidwell Friends school, just as Chelsea Clinton did.

Jeff Zeleny contributed reporting from Chicago, and Mark Leibovich from Washington.