Poll Shows Obama With 7-Point Lead In Iowa Contest

She also appeared to mock Edwards's high-octane rhetoric. "It's not something you have to do by yelling and screaming," she said. "Save your energy. Get the job done. Instead of generating a lot of heat, rolling your hands and jumping up and down, sit down and figure out how we're going to beat them."

Edwards's advisers were elated to see Clinton going after their candidate, calling it a sign of her nervousness and of the serious threat the former senator poses to her and to Obama on Thursday.

Obama also fired at Edwards during a rally in Boone on Monday. "Change doesn't come by hollering," he told more than 600 enthusiastic supporters.

Clinton advisers said their analysis of changing terrain in Iowa suggests that Edwards has peeled some male voters away from Obama, but Plouffe insisted that there has been no erosion.

"I reject any premise that we have slipped here at all," he said Sunday afternoon at Obama's headquarters in Des Moines. "We're in a very, very strong position -- growing strength every day. It's just a very close race. But I do think we have reason to be confident."

Obama's advisers convened a conference call with reporters Monday morning with a dual message: The senator is continuing to gain strength in Iowa, regardless of what other campaigns may be saying privately, but that no matter what happens here, Obama is well positioned in New Hampshire, South Carolina, Nevada and nearly a dozen states that will hold contests on Feb. 5.

Obama advisers told The Washington Post that campaign workers had knocked on 50,000 doors in Iowa on Saturday and had received commitments from 5,000 more voters. They also offered city-by-city comparisons of the candidates' crowds to argue that Obama continues to generate more energy and excitement than either of the other leading candidates.

Still, a number of Obama's advisers acknowledge that the last days of campaigning in Iowa present challenges that did not exist even 30 or 60 days ago, including attacks by outside groups.

Obama is the target of millions of dollars in advertising and direct mail, much of it negative, from groups allied to Clinton or Edwards. The groups include the American Federation of State, County and Municipal Employees, which reportedly has more than 200 workers in the state, and Emily's List -- both of which are backing Clinton, as well as a "527" group run by Edwards's former campaign manager that is supporting the North Carolinian.

"It's one against seven," Plouffe said. "I think it's pretty remarkable that through this blizzard of money we're able to hold our strength."

The three candidates have poured record amounts of money into Iowa over the past year.

Clinton and Obama will have spent $20 million to $25 million each on their campaigns here, according to strategists. Edwards has raised far less nationally and is relying in part on federal matching funds, but he nonetheless could end up having spent $12 million to $15 million in the state.

The money has gone to fund the biggest ground operations ever in Iowa, millions of dollars in TV commercials that began airing last summer and nearly a year of campaigning in the state by all the candidates.

The prodigious spending has swamped the campaigns of New Mexico Gov. Bill Richardson and Sens. Joseph R. Biden Jr. of Delaware and Christopher J. Dodd of Connecticut. But the three continue to campaign energetically throughout the state in the final days.

Both Obama and Clinton count more newcomers among their supporters than Edwards, which means if turnout is low, the North Carolinian might be favored. But Obama's advisers say they expect a record turnout, predicting that it will be between 140,000 and 160,000.

Staff writer Anne E. Kornblut contributed to this report.