When Bill Bradley decided this summer to reverse his longtime--and very vocal--opposition to federal tax benefits for ethanol, a gasoline additive made from corn, he stunned farm lobbyists and former colleagues.

But no one was more surprised than his advisers, who feared that the change would be seen as a craven sop to Iowa, where corn is the chief product, followed closely by caucuses. Some longtime aides fretted that Bradley could be squandering the image of rectitude that they saw as crucial to his campaign.

Bradley curtly informed his staff of his planned change, and later said he had "decided to listen to the people, not the policy wonks."

Often convinced that he has the answers and dismissive of much outside political advice, Bradley is largely going it alone in a season in which Vice President Gore's fleet of consultants has become one of his campaign's defining features and Gov. George W. Bush of Texas has unabashedly signed up a flock of tutors.

And while Bush fights the perception that he may be more smiles than brains, Bradley may have a different problem: He has such confidence in his own intellectual capability that he has unveiled important policy positions with little leavening from experts--and has been burned in the process.

Bradley has had to spend precious campaign time clarifying his health insurance plan after Gore seized on apparent omissions. And two weeks ago, Bradley received caustic reviews of an important foreign policy presentation that he essentially tried to wing in a presentation to students at Tufts University.

Bradley's take-me-or-leave-me independence is one of the chief sources of his appeal, and he regularly derides the fancy trappings of politics as he touts his "different kind of campaign."

But his advisers saw the downside this week, as they wrestled with a possibility that once had been unthinkable--that Bradley's foreign policy, which over his advisers' advice had emphasized the United Nations and set ambiguous criteria for the use of American force, would become vulnerable to attack from Gore during the Democratic presidential candidates' debate in New Hampshire next Friday.

Although most Bradley advisers who are involved in the discussions believe that Gore will stick to more obviously juicy issues, others are convinced that Bradley should use some of next week's debate preparation time to resolve what editorialists have argued are contradictions in his positions.

However problematic it may be for a presidential candidate, Bradley is used to being his own expert. Back in 1988, when Bradley was first thinking about whether to run for president, he got together with Henry Kissinger over matzo balls and chicken soup at the Englewood, N.J., home of a mutual friend. Their host, Rabbi Arthur Hertzberg, recalled that Kissinger seemed to be trying to impress by throwing out the names of third-tier foreign functionaries.

"Bill responded by saying, 'Oh, wasn't he so-and-so's son-in-law?' and 'Yeah, didn't he take part in an abortive revolt a few years ago?' " Hertzberg recalled. "Henry, who expected at this table to be the master of foreign policy, got a draw out of it."

Fred Greenstein, a political scientist at Princeton University who specializes in presidential leadership styles, recalls seeing Bradley a few years ago at a synagogue dedication, "not talking to anyone, just towering over the reception like an awkward, haunted figure."

Greenstein said a loner politician, while redolent of the Jimmy Stewart ideal, can be hobbled in the White House.

"If you keep your own counsel, you're in danger of seeing what you want to see," he said.

While Bush staffers proudly reel off the names of professors and political officials who are helping mold their agenda, and even bestow such titles as "chief domestic policy adviser," Bradley resists revealing whom he talks to. When the Boston Globe's editorial board asked him last month about foreign policy advisers, he said he had talked to two former secretaries of state in Republican administrations--Henry Kissinger and George P. Shultz.

Kissinger said he admires Bradley but has not talked to him since April. And Shultz introduced Bush at his full-dress foreign policy speech at the Ronald Reagan Presidential Library last month.

When Bradley was asked by Washington Post editors last week about his relationship with Kissinger, he said with exasperation, "Oh, God." Pressed on whose expertise he taps on Russia, he replied, "I don't want to go down this road."

Bradley's campaign chairman, Douglas Berman, who worked on his first Senate campaign in 1978, said Bradley relies largely on former members of his Senate staff, who have "reached out to literally hundreds of people to have conversations and discuss plans."

"There's no one person who's the guru," he said. "Bill's been studying and dealing with these issues for 18 years, so it's not fundamentally about new positions. There are people who look at the news and give current information that's digested, so he doesn't have to read every paper every day."

Berman said each of the many advisers sees a small slice clearly. "What Bill brings is a balance of judgment," Berman said. "He's who's at the center. The key to a leader is being able to ask the critical questions and assess the information to make an evaluation. That's how he has done it all his life."

Bradley's campaign has a huge issues department that has organized dozens of working groups, each with a coordinator, that draw up policy positions--usually through e-mail and later by conference call--and then submit drafts to the headquarters in West Orange, N.J.

For instance, more than 100 professors, doctors and others were shown Bradley's health insurance plan before its release, according to the campaign. But the lack of a single authoritative adviser quickly showed. Gore began arguing, based partly on details that were omitted from the plan, that Bradley's program would knock the federal budget out of balance and disproportionately hurt blacks and Latinos.

Kenneth E. Thorpe, a professor of health policy at Emory University in Atlanta who analyzed the economics of the Democratic candidates' competing proposals, said Bradley's staff sent him "a whole host of clarifications."

"They said, 'No, no, no--that's not what we meant,' " Thorpe recalled.

Despite study groups for every region of the world, Bradley also has faced criticism for the ad hoc nature of his foreign policy.

Just before Bradley appeared at Tufts near Boston on Nov. 29, his staff said that the session would be a town meeting on foreign policy and not the formal address that had been planned. The big speech was postponed indefinitely. His aides would not say why, but it soon became apparent that his policy was still a work in progress. His remarks ignored Chechnya and the United States' possible deployment of a missile defense shield, and barely mentioned China.

A column by William Safire of the New York Times, which was headlined "Tall Man Falls Short" and reprinted in many large newspapers around the country, said Bradley had "choked" at Tufts but that because of his "reputation for seriousness, was given a pass." An editorial in The Washington Post the day before said Bradley "spoke of the need for 'a new vision,' but he has yet to offer one."

Bradley's shortfall was especially surprising given his longtime passion for the topic. When he was playing for the New York Knicks in the 1970s, he ran into Stephen F. Cohen, then the director of Russian studies at Princeton University, and the two began eating together regularly.

He remains an adviser today, and views that he expresses in a forthcoming book were reflected in Bradley's talk at Tufts.

"Sometimes presidents get a few people around them who know stuff, and then they never hear anything from anyone else," Cohen said. "That would never happen with President Bradley."

Staff writer Dale Russakoff contributed to this report.