Thirty minutes after the polls had closed yesterday, Joan Hankey waltzed into Audrey Moore's election-night celebration with an exuberance as vivid as the electric red shirt, shiny white visor and seven Moore buttons she was wearing.

"I think it's going to be a smashing success," exclaimed Hankey, a 50-year-old retired Navy captain and volunteer in the "Moore Machine" that helped catapult the Fairfax County politician into the chairmanship of the Board of Supervisors.

Hankey's jubilation must have been infectious, for in short order the crowd that soon packed the Westpark Hotel at Tysons Corner was whooping and hollering as the early returns flashed over a giant television screen tucked in one corner of the grand ballroom. By 8 p.m., the result of the most ferocious local election in Northern Virginia this year was clear: Moore, a Democrat, was romping to victory over John F. Herrity, her longtime Republican nemesis on the county board.

"I think it's wonderful," said Tommy Herrity, the 39-year-old cousin of the outgoing board chairman. Moore, he declared, was "a candidate that well represents the citizens of Fairfax County."

"It's a great night for the people," added Richard Korink, a citizen activist from Centreville. "We're always talking about apathy -- the great thing about this is it overcomes that."

Even as they feasted on cocktails, beer, pretzels and chips with dip, Moore supporters suggested their festivities were more than mere revelry for one candidate's success. The night marked a more fundamental change in political leadership, they said, one that would slow what they described as too-rapid growth in the county.

Moore, said state Sen. Richard L. Saslaw, "was able to define the issue as being one of development -- and the voters agreed with her."

Others suggested that Herrity himself was a big issue in the campaign. "People are really fed up with people like Herrity," Sue Spencer, a 28-year-old real estate agent, said between sips of white wine at the Moore celebration. "They're ready for a cleaner image."

At Herrity's gathering in the Elk's lodge on Rte. 50 outside Fairfax City, the mood was far more subdued. The New Christy Minstrels, a six-piece band, remained silent throughout most of the evening, striking up a tune just before Herrity appeared to address the crowd of 800.

About 8 p.m., just as the Moore crowd was heating up, the Herrity supporters got their first taste of defeat: Early results from the bellwether Belvedere precinct showed Herrity trailing badly.

"It's over. It ain't even close. It's a wipeout," Republican Supervisor Thomas M. Davis III told a reporter.

Others clung to dreams of ultimate victory. For instance, Helen Hook, vice chairwoman of the the county GOP, predicted a win for Herrity even as fresh returns showed otherwise. Later she said she felt "like a big balloon that was up in the air.

"I just plopped," she added. "I really messed up."

Some supporters said that although they were not surprised by Herrity's loss, they were stunned by Moore's margin of victory.

"I thought it was going to be a smaller percent," said E. David Forman, a former chairman of the Fairfax County Republican Party. But, he added, "Jack's defeat is not a total defeat for the Republican Party. The party will recover."

"I always thought it was pretty close," said Jay Timmons, chairman of the Virginia Young Republicans.

Late in the evening, when Herrity appeared to address his supporters, the crowd began chanting "We want Jack!" but the chorus died after three refrains.

His brief concession speech was interrupted once by cries of "No, no, no," but he went on to congratulate Moore and asked the crowd to "join with me in wishing her and the people of Fairfax County success in the years to come."

Earlier in the day, a subdued Herrity indicated he was glad the campaign, which set new records for spending and sheer intensity, was finally drawing to a close. He likened the months-long effort to "beating yourself over the head with a hammer. It feels good when you stop."