To her longtime friends, Senator Hillary Rodham Clinton sounds unusually philosophical on the phone these days. She rarely uses phrases like "when I'm president" anymore. Somber at times, determined at others, she talks to aides and confidants about the importance of focusing on a good day's work. No drapes are being measured in her mind's eye, they say.

And Mrs. Clinton has begun thanking some of her major supporters for helping her run for the Democratic presidential nomination.

"When this is all over, I'm really looking forward to seeing you," she told one of those supporters by phone the other day.

Mrs. Clinton has not given up, in her head or her heart, her quest to return to the White House, advisers say. But as resolute as she is, she no longer exudes the supreme confidence that was her trademark before the first defeat, in Iowa in January. And then there were more humbling blows, aides say: replacing her campaign manager on Feb. 10, then losing the Wisconsin primary and her hold on the women's vote there last Tuesday.

If she is not temperamentally suited to reckon with the possibility of losing quite yet, advisers say, she is also a cold, hard realist about politics -- at some point, she is known to say, someone will win and someone will not.

"She has a real military discipline that, now that times are tough, has really kicked into gear," said Judith Hope, a friend and informal adviser to Mrs. Clinton, and a former chairwoman of the New York State Democratic Party. "When she's on the road and someone has a negative news story, she says, 'I don't want to hear it; I don't need to hear it.' I think she wants to protect herself from that and stay focused.

"That said, she knows that there will be an end," Ms. Hope said. "She is a very smart woman."

Over take-out meals and late-night drinks, some regrets and recriminations have set in, and top aides have begun to face up to the campaign's possible end after the Texas and Ohio primaries on March 4. Engaging in hindsight, several advisers have now concluded that they were not smart to use former President Bill Clinton as much as they did, that "his presence, aura and legacy caused national fatigue with the Clintons," in the words of one senior adviser who spoke on condition of anonymity to assess the campaign candidly.

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