Bill Bradley had been greeting strikers on a picket line at a box-making plant here for about half an hour when one of the organizers finally offered him a picket sign--an inviting prop for most Democratic politicians who, like Bradley, need help from labor.

Bradley declined the sign, mumbling placidly, "I'm fine." Clutching a souvenir commemorating the contract talks, he added, "I have the T-shirt."

It was an awkward moment, and it was suggestive: The former New Jersey senator, who hopes to give Vice President Gore a scare in the Iowa caucuses 12 days from now, appears to be struggling to connect with voters at a particularly crucial juncture of the presidential campaign.

In his insurgent bid for the party's nomination, Bradley has captivated many Democrats with his lofty rhetoric and an unconventional approach to politics that includes emphasizing only a few big issues and zealously guarding his privacy. Here in Iowa, however, Bradley's quirky, even endearing, characteristics have begun to look more like liabilities to some voters.

It is one more factor making life difficult these days for Bradley, who is looking for a big boost out of Iowa heading into the Feb. 1 New Hampshire primary. Instead, his usually sure-footed campaign appears to be stumbling a bit. On Saturday, in the first Iowa debate, Bradley had trouble deflecting Gore's contention that Bradley voted 15 years ago to deny flood relief to farmers. A few days later, he attacked Gore with uncharacteristic ferocity in questioning his commitment to discourage youth smoking, but his evidence was a 15-year-old vote and a 12-year-old letter to the editor.

Bradley's biggest problem, however, may be an awkward campaign style--the Gore camp derides it as professorial--that seems to be turning some voters off in both of the key early contests, but particularly in Iowa. Leaving a Bradley appearance in Boone, Iowa, this week, Anne E. Darby, 45, an assistant in a high school classroom, mocked his stump speech, with its "world of new possibilities, guided by goodness."

"Who does he think he is?" she asked.

Kimberly C. Rivas, 34, of Clive, Iowa, the mother of two daughters, was one of several voters interviewed this week who believe Bradley has treated Gore contemptuously in debates.

"I would hope the president would be smarter than me, but he doesn't need to keep bringing it to our attention," Rivas said.

Although many of Bradley's supporters are drawn by his idealism, a questioner at a debate last week asked the former Rhodes scholar, Olympian and pro basketball star about the perception that he is aloof.

"Take a look," Bradley replied. "Am I aloof? I'm not aloof at all. The best thing I like about politics is going out and meeting people. I've just finished my 46th town meeting in New Hampshire."

Bradley's communications director, Anita Dunn, said the campaign is pleased with the support it has generated, and has always known it would have a tough fight in both states, especially Iowa. "In the course of a basketball game or a campaign, the rhythm ebbs and flows," she said. "You have to keep your eye on your game plan, stick to it, and you succeed. That's been the story of our campaign for 13 months."

As Bradley scrambled to regain his footing, he flew to Manchester, N.H., today, using the airborne time to inspect the weather map in the New York Times and chat with reporters as part of a late-breaking friendliness offensive. He plans to take half a day off on Thursday to return to his New Jersey home, and then return to Iowa until the caucuses.

With time running out, Bradley seems to still be groping for ways to explain his high-minded ideas. In Ankeny, Iowa, on Tuesday night, Jared Feverhelm, a freshman at the University of Iowa, told Bradley during the question period that Gore had succeeded in widely spreading the accusation that under Bradley's health insurance plan, Medicaid recipients would be reduced to $150 a month in services.

"It sounds frightening," Feverhelm said. "What I am concerned about is I haven't read or heard in any of the debates . . . how you intend to have it work."

Bradley said, "Good--I think that's a legitimate question." He went on for 800 more words, complete with two references to a "weighted average," pausing at one point to say, "Not to get too complicated."

Acknowledging that the plan was not simple to explain, Bradley said, "That's the risk you take if you're trying to lead on a big, complicated issue."

Gore has tried to capitalize on Bradley's style. In an open meeting today in Cedar Rapids, Iowa, Gore ridiculed Bradley's intellectual approach to governing. Listing numerous issues now on the public agenda, Gore said: "The president . . . should not approach it as kind of an academic exercise or seminar pursuing just one or two big theories or ideas."

At a focus group conducted by The Washington Post in Bedford, N.H., after a recent debate, several participants were critical of Bradley's style. "I could see the expression on his face every time Gore was speaking," said Susan Lewandowski, 39, a word processor from Hollis, N.H. "He was, like, smirking, and he was arrogant."

Raquel Perez, 42, a high school Spanish teacher from Merrimack, N.H., agreed. "I cannot stand an arrogant man," she said. "I think I counted four smirks."

In an interview, Bradley reacted with disdain to a question about his alleged aloofness.

"Would you prefer an un-serious approach?" he asked.

But Bradley's style has even elicited scoldings this week from his wife, Ernestine, a comparative literature professor who recently joined him for several campaign stops. At the picket line, she bridled as Bradley tried to pull her away from a striker so he could keep moving. "Bill, I'm trying to understand this," she said with real annoyance, snug in her trademark earmuffs.

Bradley still has the rhythms of his days with the New York Knicks basketball team, often boring audiences in the morning but occasionally coming on like a nightclub host after dark. At an evening speech in Council Bluffs, Iowa, Bradley mocked himself when an audience member said he found the candidate to be dynamic, in contrast to his reputation as a slow talker.

"Wellll," Bradley said, grinning as he switched to a robotic slow motion. "That's part of my styyyle--when I want it to be." He went on to praise the shirt and even the shoes of people who asked him questions. A few nights later, he quizzed an audience member about what he had for dinner.

As Gore traverses the Hawkeye State in Dockers and a knit shirt, Bradley has stuck with blue Oxford shirts and red ties. Preparing to speak at a livestock auction house, with sawdust in the ring and all the appropriate smells in the air, Bradley made a concession to his environment. He traded his suit coat for a V-neck sweater, but kept the tie.

Staff writer Ceci Connolly in Cedar Rapids, Iowa, contributed to this report.

CAPTION: Bill Bradley points to a student during his visit Tuesday to an elementary school in Des Moines.

CAPTION: On Tuesday in Ankeny, Iowa, Bill Bradley gave a lengthy and technical explanation of his health care proposal.