One question is whether senior Democrats who are trusted by the candidate and her husband will ask her to consider quitting the race  politically savvy elected officials such as Gov. Edward Rendell of Pennsylvania or Gov. Jon Corzine of New Jersey, or friends with wide connections in the Democratic Party, such as Vernon Jordan or Robert Rubin. (Mr. Rendell and spokeswomen for him and Mr. Corzine did not return phone calls on Tuesday night.)

“I wouldn’t be surprised at all if a Rendell or a Vernon Jordan was prepared to weigh in with the Clintons, because the path to the nomination is just looking tougher for us,” said one top fund-raiser for Mrs. Clinton and longtime friend of the couple, who spoke on condition of anonymity to describe his mood and that some other fund-raisers.

“Many of us thought she had to win both Indiana and North Carolina to show that she could pull off surprises now in order to pull off the biggest surprise of all  winning the nomination despite being behind right now,” this fund-raiser added. “And she didn’t.”

Some independent political analysts said Tuesday night that it is almost a certainty  at this late stage of a primary campaign, with 50 primaries and caucuses concluded and only 6 left  that the Clintons and their closest supporters would at least discuss whether she should continue to battle Mr. Obama. It may only further weaken him if he emerges as the nominee; tarnish him in potential swing states that still have primaries, such as West Virginia; and also hurt Mrs. Clinton’s chances of being selected as his running mate.

“The campaign may go on but the contest is now over: Obama is the Democratic nominee for president,” said Robert Shrum, a Democratic strategist who was a senior adviser to the Gore and Kerry presidential campaigns. “Now the decision for her is how she wants to end this.

“The people who have her best interests at heart, they would now say to her, ‘You ought to really think about not protracting this, because you will only look selfish in the weeks to come,’ ” Mr. Shrum said. “Her Pennsylvania win bought her permission to go on. But then her narrow victory in Indiana and this smashing defeat in North Carolina  there is no rationale for her to continue.”

One Clinton adviser called the North Carolina loss in particular “a very significant turning point” because Mrs. Clinton, the former president and some of their advisers had become so excited about their prospects of a surprise victory there. Instead Mr. Obama beat her there by about 15 percentage points.