Throughout his uphill bid for the Democratic presidential nomination, John Edwards was emphatic that he had no interest in being vice president.

"I'd be happy to consider Senator Kerry as my running mate," Edwards would often say, politely but curtly, when reporters asked whether he would consider the second spot on the ticket.

But since Kerry announced nearly three weeks ago that the North Carolina freshman senator was his choice for the No. 2 spot, Edwards has campaigned with as much gusto for Kerry as he did for himself when he was seeking the top job.

"The truth is, there is no one better prepared to keep the American people safe than this man," Edwards repeatedly told audiences during his first days on the ticket. "If you have any question about what John Kerry's made of, about his leadership ability, about his strength and his courage, just spend three minutes -- three minutes -- with the men who served with him 30 years ago, who still stand by his side."

Glenn Bergenfield, a law school buddy of Edwards and his wife, Elizabeth, said he believed his friend was sincere when he insisted during the primaries that he was not seeking the vice presidency.

"There's a certain point when you know -- and this happens in lawsuits, as well -- that sometimes you're not going to get it your way exactly," said Bergenfield, who said Edwards also has always had "a burning sense to be of use. So, I think he said, 'Okay, I didn't win. How can I help here?' "

Edwards, 51, also has a large ambition to be president, said Stephen Hess, a senior scholar at the Brookings Institution who is an expert on the presidency, adding that the more effectively and enthusiastically Edwards embraces the role of vice president -- in the campaign and if elected -- the better that will serve those ambitions.

Most people who study or participate in presidential politics agree that the office of the vice presidency has grown in stature during the past decade. The vice president's only constitutional mandate is to preside over the Senate and break tie votes. Many cite Vice President Cheney and Al Gore, second in command to former president Bill Clinton, as perhaps the most active and influential vice presidents in history -- and both came to the job with years of government experience.

Edwards has little experience in Washington or in politics -- his first electoral contest was for the Senate seat he now holds -- so there are fewer clues to how he would respond to the office. Before that, he had spent 20 years as a trial lawyer, winning multi-million-dollar settlements in medical malpractice and personal injury lawsuits. Republicans have argued that he lacks the experience to run the country, if he had to assume the presidency.

Kerry dismisses that charge, but in an interview with Edwards shortly after he picked him, Kerry said, "Does [Edwards] have as much experience as me? No. But I am running for president; he's running for vice president."

Edwards noted, however, that he will do everything he can to reassure people of his capacity to handle the job. "I have an obligation to the American people to work 18 hours a day . . . to make sure that every day I know more than I did the day before," he said. "I feel that responsibility [and] take it very, very seriously."

Edwards declined a request for an interview for this story. When asked on "Larry King Live" last week about how he and Kerry see the role of the vice president, Edwards was vague. "I think both of us want this to be a strong and powerful partnership where we trust and rely on each other. I think it's still an evolving partnership right now because it's still pretty young. But I feel very, very good about how this is going," he told King.

His allies say Edwards is intelligent and a hard worker and is up to the job.

"He has the vision and the values to meet the challenges of our time," said Sen. Edward M. Kennedy (D-Mass.), a mentor to Edwards.

Hess said that Gore and Cheney complemented their bosses, governors who had little or no Washington experience. Both were trusted advisers and oversaw major initiatives in their administrations.

Kerry, a four-term senator from Massachusetts, knows his own way around Washington. Still, Hess thinks Edwards will play a significant role for Kerry because "he's smart and talented, and increasingly the habit is to use" vice presidents to help achieve the goals of an administration. Hess predicts that Edwards would be able to tamp down his ambitions and serve Kerry because "he wants to be president, and at this point his immediate chance to be president is to be vice president. And his chances depend on the success of Kerry."

William Mayer, a political science professor at Northeastern University, is not sure Kerry and Edwards will mesh as political partners. "It remains to be seen how much Kerry really respects this guy's thoughtfulness and knowledge," said Mayer, who believes Kerry's first choice was Sen. John McCain (R-Ariz.). "Kerry's been saying lots of nice things about him since selecting him, but back when they were running against each other, he clearly expressed a certain amount of disdain about Edwards's knowledge of issues."

Bruce Reed, president of the Democratic Leadership Council and an Edwards ally, said that is no longer the case. "We've already seen what a good partner he makes for John Kerry," he said, referring to Edwards's enthusiastic campaigning.

"He helps Kerry be Kerry, and they have a common agenda, a common world view," Reed added, noting that Kerry is looser with Edwards at his side. "The presidency is a very lonely job, and I think a President Kerry would welcome having a vice president around to share the burden."

During the primaries, Edwards focused on domestic issues, winning praise for his message of uniting "two Americas -- one for the privileged and one for everybody else." But critics at that time, including Kerry, noted that he had little foreign policy and national security experience, and polls showed that in the post-Sept. 11 world voters want a president who makes them feel safe.

Asked how Edwards stacked up to Cheney, who was a defense secretary, White House chief of staff and served a decade in the House, President Bush said: "Dick Cheney can be president."

A recent poll by the Annenberg Public Policy Center of the University of Pennsylvania showed Cheney won much higher marks on the question of "experience to be president." But Edwards edged out Cheney, 38 percent to 36 percent, on favorability and had much lower unfavorable ratings -- 24 percent to 39 percent.

Bergenfield, who met Edwards while attending law school at the University of North Carolina at Chapel Hill, said the professional life of a trial lawyer can be somewhat solitary, but he thinks Edwards also can be a team player.

"As a trial lawyer, you basically have to trust your own judgment, but I wouldn't call him a loner," Bergenfield said. "He's his own man [but] he understands that John Kerry is in the first chair."

Sen. John Edwards (N.C.) dives into the crowd at the Fillmore auditorium in Denver, where he and Sen. John F. Kerry (Mass.) spoke.Campaigning in Albuquerque are, from left, Edwards, his wife, Elizabeth, Teresa Heinz Kerry and the presidential candidate, Kerry. New Mexico is considered a swing state.