Four years ago, when she was mounting her first race for the Fairfax County Board of Supervisors, Lilla Richards (D-Dranesville) said something to the effect that voting her conscience might make her a one-term supervisor.

Her prediction may come true, and in the process she inadvertently may make Board Chairman Audrey Moore's rebellion against development a one-term uprising.

With Richards's reelection in jeopardy, Moore's fragile core of five no-growth Democrats also is at risk. Republicans are salivating at the chance to regain control of the board and reverse Moore's land-use policies.

"She not only votes right, but she's knowledgeable enough to be an asset on the board," Moore said. "She's an extremely important ally in this effort to balance growth and transportation."

In part, Richards is caught in a political cross-fire that is affecting politicians throughout Fairfax.

As in other parts of the county, transportation and taxes dominate political talk in her district, which ranges from millionaire mansions to blue-collar split-levels.

But Richards also carries self-imposed burdens: a prickly public persona and a willingness to cast impolitic votes that have made her vulnerable.

Republican Ernest J. Berger, an administrator at George Mason University, is expected to mount a serious challenge this November by tapping Dranesville's Republican leanings and its deep voter resentment over property taxes.

Richards's political liabilities came into clear focus at a recent board meeting where the air was especially thick with politics in this election year.

With two votes, Richards, 51, a slow-growth Democrat from a conservative district, succeeded in offending her strongest political base and firming the resolve of an anti-tax group that already loathes her.

"Here's a lady who may be her own worst enemy, but she really believes in things," said Supervisor Thomas M. Davis III (R-Mason), who sits next to Richards in board meetings and is running against Moore for board chairman this year. "She does not posture."

With Moore and Davis jockeying for political points, Richards was the only one of nine board members to vote against a resolution urging the state legislature to limit property tax assessments. Even though the tax assessment limit was going nowhere in Richmond and her district was the cradle of a vigorous tax rebellion, Richards said, she rejected the measure as "cynical and political," committing what one member called "political suicide" in the process.

"The fact that she isn't willing to give vocal support for any type of cap should show the citizens where her true colors are," said Marcia Dykes, a founder of an anti-tax group and one of Richards's most vocal critics.

Shortly after angering her district's tax rebels, she enraged Herndon civic activists whom she had courted for the last three years by voting for a large park-and-ride lot in their town.

The size of a park-and-ride garage may seem insignificant to some, but it is no small matter to many of the 16,129 residents of Herndon, who want to limit the number of spaces to 500 to keep traffic out of downtown.

Transportation experts want 1,790 spaces to handle the demand of the county's express bus system in the Dulles corridor and the possibility of expansion if rail transit comes.

"Right now, the marriage is on the rocks," said Les Zidel, a Herndon Democrat, after the board approved the larger parking lot. "To make a prediction that she's blown it, I wouldn't say that. But I have to tell you, there's been a lot of hard feelings. She's going to have to do a lot of mending fences."

Moore and Davis, trying to grab votes in the race for board chairman, voted to keep the parking more to Herndon's liking.

Moore even left her seat after the vote to go into the hall and express her regrets that they did not get what they wanted.

"Tom told me he didn't have any choice," Richards said of Davis's vote. "And {Moore} came off as the hero."

"I said I'm a lousy politician," Richards said. "I don't like to lie to the voters."

That kind of blunt speaking may earn her credit for honesty, but it is not the talk that keeps politicians in office very long.

Richards ran for supervisor four years ago, at Moore's urging, after a long history as a vocal slow-growth activist in McLean. Richards defeated a split ticket of Republican incumbent Nancy Falck and independent Robert Thoburn.

In the days of citizen activism, in which her mastery of zoning law helped her arguments at public hearings, "there was a luxury of not having to vote on things for a partisan political reason," Richards said. "I think there are a lot of people out there looking for elected officials to vote on facts and what's best in the long run, not just for short-term political gain."

Richards's personality not only rankles politicians but also injures her relations with some members of the news media. She once left a snakeskin on the desk of a reporter, and she said she now declines to take questions from the reporter unless they are written.

For the past two years, she has come under increasing criticism from Dykes and her Great Falls anti-tax group, Citizens for Sensible Taxation, whose members say Richards is not attuned to the plight of homeowners facing huge property tax increases.

During the flurry of publicity after the group surfaced, Richards made a statement that the head of the group was in "need of a little civics instruction."

For two years, Richards repeatedly has complained to The Washington Post that the quote was incorrect and taken out of context. Richards said she was besieged by mail and telephone calls from angry residents for months afterward, and to this day laments that the quote still haunts her.