In the clubby world of Beltway political consultants, breakups between candidates and their advisers are supposed to be handled quietly and with restraint.

So people in that circle were stunned this week when Alan Secrest, one of the most successful pollsters in the nation, tossed aside his 20-year relationship with U.S. Rep. James P. Moran and publicly accused the Alexandria Democrat of making an anti-Semitic remark during an internal campaign meeting March 18.

Moran, who is being challenged Tuesday for his party's nomination, denies making anti-Semitic comments and says the dispute with Secrest was about how much money the campaign owed Secrest's polling firm.

Secrest said Moran's comments, which he refuses to describe, were the "tipping point" in a frustrating and sometimes volatile working arrangement with Moran that needed to be ended. Secrest said a letter he wrote to Moran on May 25 ending their relationship was designed to quash the inevitable rumors about why he quit shortly before the primary.

"On the street, in back corners, in the cloak room, there's a whisper campaign" when candidates part ways with consultants, Secrest said. "I decided we would make clear we were leaving on our terms."

Moran said Secrest was trying to hurt him politically by taking advantage of his perceived vulnerability to criticism from Jewish voters. "Mr. Secrest may have seen an opportunity, and he chose to exploit it," he said.

Political operatives and other campaign officials said Secrest's very public denunciation of Moran is highly unusual and could hurt his ability to attract clients.

"You put your trust as a candidate into three people: your manager, your media consultant and your pollster," said Steve Jarding, who managed the 2001 campaign for Gov. Mark R. Warner (D) and is close to several Moran aides. "These are the guys you open your heart to. They know every wart. They know where every body is buried."

Still, it's hardly unique for tempers to flare during the heat of a campaign, and candidates often part ways with consultants. Chris Lehane, who quit John Kerry's presidential campaign during the Democratic primary in a dispute over the campaign's direction, went to work for Gen. Wesley Clark, then a Kerry rival. In that role, he distributed information to reporters that portrayed the Massachusetts senator negatively.

But Peter Fenn, a Democratic political consultant, said the Moran-Secrest clash is "unusual" because it happened so close to the primary and was so public.

Secrest said he's not worried about how his public split with Moran will affect his business.

"I extended respect to Jim for an awful long time," he said. "At some point, matters of integrity take over. If there's someone who is not interested in candor, I guess they won't hire us."

In the realm of top political pollsters, media advisers and campaign managers, Secrest has been a sought-after commodity -- someone who has proven that he can help candidates win.

A pollster for decades, Secrest has run the firm of Cooper & Secrest since 1985. Since then, the firm has helped elect more than 300 members of Congress and hundreds of state legislators and city council members.

His supporters say he is a brilliant, if intensely opinionated, pollster able to divine public sentiment and help clients craft a message.

In 2002, he helped Maryland state senator Chris Van Hollen (D) win a primary against a member of the Kennedy clan and go on to claim the seat held by former Republican representative Constance A. Morella.

"Alan is one of the best in the business," said Steve Jost, Van Hollen's campaign manager. "I've worked with him in races where his polling has been so good, my clients have been able to beat folks with four times the financial advantage."

Detractors say he is hotheaded and occasionally a ruthless competitor whose short fuse and abrasive personality lead him to say and do things other consultants wouldn't.

"He is a good pollster and he has a very good political mind, but it doesn't surprise me that he did this because he can be very vindictive at times, with candidates who have done him wrong or with former employees," said Dan Cooper, a former Secrest employee who said he was sued by Secrest over a non-compete clause in his contract.

Gail Nardi, a longtime Democratic operative in Richmond, said Secrest clashed with state Democrats during the 1995 state legislative campaigns. "This would not be the first example of Alan Secrest being overcome by temper and vindictiveness when his will is outvoted," Nardi said.

Several political strategists said Secrest has on several occasions dashed off harsh letters that later became infamous in the gossipy, back-biting arena of national politics.

Political consultants recall a missive he sent to Rahm Emanuel, then an operative with the Democratic Congressional Campaign Committee and now a member of Congress from Illinois.

It was 1988, and Secrest had clashed repeatedly with Emanuel, who sent Secrest a dead fish, accompanied by a note that said, "It's been awful working with you." Secrest shot back with a letter:

"So often, those who fail most spectacularly in our business are those for whom the involvement in politics becomes a desperate (and ultimately doomed) attempt to prove their manhood," Secrest wrote, according to a transcript in Campaigns & Elections magazine.

Emanuel did not return calls left at his Washington office. And Secrest dismisses any discussion of that letter as irrelevant to his decision to quit the Moran campaign.

"We try to come to closure with every campaign," Secrest said. "Most of our clients are loyal, as we are to them."

Staff writer Lisa Rein contributed to this report.