Recapturing the energy of his brightest days on the campaign trail, President Obama attempted yesterday to pull his signature health-care initiative out of the summer doldrums with a plea for help from thousands of his most dedicated supporters.

"This is the hard part. This is when the special interests and the insurance companies and the folks who want to kill reform fight back with everything they've got," he told a cheering crowd at the Target Center in Minneapolis. "This is when they spread all kinds of rumors to scare and intimidate the American people. This is what they always do. That's why I need your help."

With his sleeves rolled up and without a tie, Obama used the spirited rally to move into what strategists optimistically call the "closing chapter" in his quest for sweeping changes to the nation's health-care system.

"We're now in the phase where we have to close the deal," said Anita Dunn, the White House communications director.

Though the speech was substantively the same as the one he delivered to a joint session of Congress on Wednesday, the difference in setting and enthusiasm could not have been starker. Obama, who often speaks in professorial tones to explain his health-care plan, adopted a preacher's cadence yesterday.

Slowly, he unspooled the oft-told story of the petite lady in the "church hat" in Greenwood, S.C., who first uttered what would become his presidential campaign's rallying cry: "Fired up! Ready to go!"

The story, he said, proved "how one voice can change a room."

"If it changes a room, it can change a city," he continued. "If it can change a city, it can change a state.

"And if it can change a state, it can change a nation," he said, reaching a crescendo. "It can bring health care to every American."

"They can't stop us!" he bellowed.

After the "drift" of August, Obama is attempting to "turn hope into success," said informal adviser John Podesta. In the coming weeks, the president and the extensive resources he commands will be used to lavish attention on two groups: Democratic lawmakers and middle-class Americans who are anxious about how the cost of extending coverage to tens of millions of the uninsured will affect their own health insurance and finances.

Vice President Joe Biden, who spent 36 years in the Senate, has stepped up his involvement, meeting with many of his former colleagues. Cabinet members are hitting the road and giving interviews in targeted media markets. Agriculture Secretary Tom Vilsack, for example, is making the rounds of rural radio stations, while Labor Secretary Hilda Solis is appearing on Spanish-language television.

As negotiations on Capitol Hill intensify, Podesta said senior White House advisers would begin entertaining more specific requests from lawmakers - for a presidential visit to the district, for example, or a particular change in a federal health regulation.

At the heart of the strategy is a message to millions of insured-but-anxious middle-class Americans that one of the most popular features of Obama's proposed package - underwriting reforms - would be felt immediately, Dunn said.

Under the legislation, insurers would be prohibited from onerous practices such as denying coverage to people with pre-existing conditions, placing annual or lifetime caps on coverage and imposing unlimited out-of-pocket fees. Although many elements of reform would take months or years to implement, the insurance changes could take effect "the day after" a law is signed, Dunn said.

Senate Minority Leader Mitch McConnell issued a statement in anticipation of the president's rally, warning that the Obama proposal was too costly and would undermine Medicare. "The problem isn't the administration's sales pitch," McConnell, a Kentucky Republican, said. "The problem is what they're selling."