In September, Mr. Axelrod, Mr. Hildebrand and some policy experts went to the house of donor Judy Wise in Chicago to update supporters on Mr. Obama’s positions on key issues and to reassure his top contributors that the campaign was performing well. They seemed receptive—to a point.

“Steve Hildebrand did a very good job of reassuring people that in the early states he is very competitive,” said Ms. Wise. “Obviously, they have made some choices here.”

She said she was personally not discouraged by Obama’s trailing in national polls, and said that on several conference calls, Mr. Obama himself had told donors, “‘Look at what is going on in these states where we are really focusing our energy and where our ads are running, look at those polls and how quickly things can change if things go well in those early states.’”

Another prominent Obama donor, based in New York, said that Mr. Plouffe had visited New York recently to explain to donors the campaign’s strategy of concentrating on early primary states.

The donor said that he had been hearing some fellow donors express frustration about Mr. Obama not taking a more aggressive stance against Mrs. Clinton. “It’s definitely the case that they are not doing anything overtly aggressive to attack her, and my view is that she has gotten, by and large, a free pass,” said the donor. At the same time, the donor said a sharper pitch would be inconsistent with Obama’s image and “was not what this campaign wants to do. And I completely support that.”

Toward the end of Mr. Obama’s rally in Washington Square Park on Sept. 27, the candidate told the crowd, without mentioning Mrs. Clinton by name, “There are easier choices to make in this election. There are safer choices to make.” He continued: “There are competent people who will manage the system as it is and will tinker around with things and certainly will be an improvement over George Bush.” He left the larger point—that he was more than merely “competent”—unspoken.

After he finished talking, Mr. Obama shook the hands of the front rows of ecstatic supporters while the speakers played the lyrics “Everything’s going to be alright” from a song called “Believe.”

“He’s building credibility for the long term,” said Josh Marcus, a 19-year-old business student at N.Y.U. who said he supported Mr. Obama but doubted he would win the nomination in 2008. “He is a young guy who is going to be around for a long time.”