Bill Bradley's first television ad promises "a different campaign," one free of the bickering and backbiting that he believes is the real root of voters' weariness with politicians.

So who was that tall, pensive fellow who over the last two weeks accused Vice President Gore of using poor people "as political footballs," of being "too timid" on gun control, of failing to stand and fight for health care for all, of abandoning fundamental Democratic principles, and of being either inefficient or insincere in his opposition to new oil drilling off California's coast?

It was Bill Bradley, testing the boundaries of chivalry that have been set for him by 35 years of generally favorable press coverage and by his self-described "obsession with rectitude" and "desire to be super-clean."

With Bradley now racing Gore belly-to-belly for the Democratic presidential nomination, the 10 weeks until the New Hampshire primary have become a test of whether the high-minded campaign that Bradley has promised--and that his most loyal supporters expect--remains feasible in a political culture accustomed to the slash-and-trash.

And for the first time since he became a Princeton basketball phenom with Sports Illustrated as his scrapbook, Bradley can expect his golden aura to be relentlessly scrutinized for signs that he may be just another politician.

In an interview last week, Bradley, 56, acknowledged that his different kind of campaign may get to look more conventional very quickly, although he blamed Gore for pushing first.

"When people are voting for president of the United States--the most intimate decision they have to make in politics--what they want above all is to know what the positive vision is of the person who is running, and not attacks," he said in his deliberate, professorial tone.

"If we're in a situation where he's misrepresenting who I am and what I believe, then quite frankly you have to say what the truth is--you have to counter that. And so I will do that."

Bradley said the vice president had subjected him to "eight or 10 different kinds of attacks, which I think reflects a certain desperation--forget 'desperation'--a certain deep lack of confidence."

Bradley seemed to be telling voters that the coming barrage is going to hurt him more than it's going to hurt them. "I'm a competitor," he said. "But I want people to understand what my intention is, what my goal is. We'll go from there."

Sen. Paul D. Wellstone (D-Minn.), one of the few senators to endorse Bradley, said joining the fray carries great risk. "What's working for Bill Bradley is his chemistry with people," Wellstone said. "People like Bill because he's different. I don't think Bill needs to--or should--get involved in tit-for-tat with the vice president."

And some longtime Bradley-watchers believe he will almost surely be diminished by the duel ahead. "Active campaigning is rarely an ennobling experience," said Ross K. Baker, a political scientist at Rutgers University in New Brunswick, N.J. "Even though he appears silver-plated now, some tarnish is going to develop."

Sen. Bob Kerrey (D-Neb.), another Bradley supporter, said that with the race tightening, the candidate can expect a torrent of advice telling him to change to a more conventional approach. Kerrey believes Bradley will resist. "He can stand in the middle of the storm and say, 'This is who I am,' " Kerrey said.

Paul Taylor, executive director of the Alliance for Better Campaigns, which promotes voter engagement in the political process, said this post-Lewinsky campaign season provides an opportunity for a virtuous candidate similar to that exploited by Jimmy Carter after Watergate. "There's always a market for straight talk and honesty, but in this climate, the yearning is even stronger," Taylor said.

In contrast to Bradley's sharper jabs of recent days, he was more restrained earlier in the campaign--even when presented with the opportunity to land a punch. At a joint appearance with Gore in New Hampshire last month, for example, Bradley was asked to comment on the Clinton administration's fund-raising behavior. "I think there were obviously some irregularities that have been addressed," he said. "I'm not going to get into the details at this stage of the game."

Since he announced his quest 11 months ago, Bradley has been campaigning against campaigning. His half-glasses slide down his nose, he jabs his hands into his suit pockets and when he pulls them out, the flaps stay hidden. He sucks Vitamin C drops and continually swishes his tongue under his lips and cheeks, as if cleaning his teeth. He is rumpled and bland--and proud of both.

"Don't look for any deep, manipulative impulses," Bradley told a reporter who had just begun covering him. "There it is: If that's what people want, I win. If it's not, I don't."

In his role as the un-candidate, he playfully mocks campaign rituals. In September, he said on ABC's "This Week" that he had used marijuana several times, but never cocaine, then asked the panelists, "Have you?" Bradley aides say the fund-raising phones lit up with new supporters.

He even claims to disdain the tools of modern politics. Asked by a reporter in New Hampshire why polls have shown his support is stronger among men than women, he replied wearily, "I don't know who's for me or who's against me, demographically."

That may seem surprising for a candidate who spent more on polling for his 1990 reelection effort than any other Senate candidate that year, and who began testing the presidential waters by polling beyond New Jersey back in 1987.

For this campaign, Bradley has had a full-time pollster on staff since summer, and has spent more than $170,000 on polling.

Sharpe James, the longtime mayor of Newark, New Jersey's largest city, supported Bradley in each of his three Senate campaigns and even once shared an office with him. But he has endorsed Gore.

"Bill Bradley is nothing but smoke and mirrors," James said. "He's a lovely person to have over to the house. But it's hypocritical for him to say that he's not going to indulge in negative campaigning and manipulation, when he's running as an outside person after 18 years in the Senate."

However calculated, Bradley's blase dismissal of polls is part of an image of authenticity that supporters at his rallies and fund-raising receptions repeatedly point to, rather than any specific accomplishment or proposal. As Bradley met with Jewish voters in Atlanta last week, Murray Camhi, 84, said the candidate reminded him of Abraham Lincoln--and that it wasn't the height.

"He isn't a rabble-rousing kind of speaker, but he has a fairness and squareness," said Camhi, a retired ready-to-wear salesman. "I like his sincerity."

Along the back of the room, the campaign had set out platters of potato latkes.

Despite such gestures, Bradley chafes at media coverage suggesting that campaigns are inherently cynical. Last Monday, the day after his Madison Square Garden fund-raising bash featuring his former New York Knicks teammates, Bradley held a news conference with Robert B. Reich, who was labor secretary during President Clinton's first term and defected from Gore to endorse Bradley. A reporter asked if the back-to-back events were designed "to show the many facets of Bill Bradley."

"Yeah, precisely," Bradley said sarcastically, as the room filled with chuckles. "That was the whole strategy. We're manipulating all of you just beautifully."

Two days later, Bradley retold the exchange with relish, including affecting a pompous, Ted Baxterish tone as he posed the question.

Although Bradley mocks such inquiries, his campaign has availed itself of a Madison Avenue team that has spent the last 17 months crafting Bradley's ads, which sport the Nike-esque tagline "It can happen."

Under questioning by 40 reporters who showed up for a viewing of his first two campaign ads at a Washington law firm last week, Bradley's communications director, Anita Dunn, conceded that the campaign had used focus groups, but maintained that the ads were "not shaped by the research."

"This campaign is about Bill Bradley--about what he believes, where he wants to lead the country," she said. "We had not done any research in terms of coming up with what Bradley was going to talk about in the course of this campaign. That was Bill Bradley's decision a year ago."

In the interview, Bradley said he believed there was no conflict between his desire to remain unpackaged and his many long meetings with strategists who wrestled with "Bradley as a brand." He said his goal was for them to get "to really know you so they could use their creative genius to project to the larger audience your true self."

"The first meeting I had with this team, assembled by a friend of mine, I gave 'em all copies of my book," he said. " 'Here--read it. The purpose here is to get to know me.' "

Bradley made it clear that he is in the race to win, not as a contribution to democracy or to make a point about political dialogue. Asked how he will know whether he achieved his different kind of campaign, Bradley replied, "I think the yardstick will be whether we can remain disciplined in our strategic plan."

Staff writer Dale Russakoff contributed to this report.