John Edwards (search) sought Thursday to distinguish himself from the bitterly divided Democratic presidential field by casting himself as the one candidate who speaks ill of no other.

"People are sick and tired of negative politics. They are looking for a president they can be proud of," the North Carolina senator told 500 cheering supporters squeezed into a downtown hotel conference room.

With star-shaped confetti and blaring rock music, the rally allowed Edwards to contrast his self-consciously upbeat campaign to the spate of critical ads, mailings and telephone calls coming from other camps in a close four-way race for Monday's caucuses.

Howard Dean (search), Dick Gephardt and possibly John Kerry (search) sit atop the field, with Edwards trailing slightly but gaining supporters, according to campaign pollsters and strategists who are having an unusually difficult time handicapping the race.

Anything less than victory would be a blow to Dean and Gephardt, who have led in state polls for weeks. Expectations are lower for Edwards and Kerry, thus a second-place finish would give them an enormous boost.

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Looking for a route to the top tier, Edwards and his advisers decided the best way to recruit undecided voters would be to stick to a positive, policy-driven message that saves his criticism for President Bush.

"If you're looking for the candidate who can do the best job of sniping at other Democrats, I'm not your guy," he said.

Claiming momentum, Edwards said, "The best test is I'm now being attacked by everybody."

Gephardt has listed Edwards among the candidates who have supported free-trade deals. Dean has named Edwards as one of the hopefuls who backed Bush's war resolution on Iraq.

But none of the negative ads airing in Iowa single him out for criticism. And asked whether any of the ads were inaccurate, Edward's told reporters, "Not that I can recall."

His advisers said Iowa voters are getting telephone calls distorting Edwards' record on hog farms, a sensitive issue in the state.

Still, the candidate said, "I am not a victim. I'm somebody who's running a strong, positive campaign." He stopped short of swearing off critical ads for the entire campaign, saying he would respond to any distortions of his record.

Edwards is not above a subtle jab. The first-term senator said "people who have been in politics all their adult lives" aren't the best advocates of change, a reference to his rivals who have spent more time in Washington than he.

The crowd was large for a lunchtime event. The floor vibrating beneath their feet as John Mellencamp's "Small Town" blasted from speakers, several Edwards supporters said they were finally beginning to believe he could do surprisingly well Monday. But few gave him much of a chance for victory.

Edwards wagged his finger and shook a fist as he urged the crowd to vote. "If I could reach out there and grab you by the shirt, I would do it," he said with a high-voltage smile.