Loudoun County Board of Supervisors Chairman Scott K. York has spent 15 years on the board as both a Republican and an independent. (Tracy A. Woodward/The Washington Post)

The chairman of the Board of Supervisors was retiring, and now he isn’t. His preferred successor was pushed out of the race following revelations of a history of domestic violence and drunken driving. On his way out, he accused his opponent of trying to blackmail him with damning court documents.

Welcome to Loudoun County, a booming exurb about an hour west of Washington, where dramatic political shifts and intrigue have been par for the course for years.

The wealthiest county in the nation — and the fastest-growing one in Virginia — Loudoun is known for its sometimes excruciating traffic and underfunded schools. And under Virginia law, it has no way to deal with either other than by raising property taxes.

Add a swinging, independent electorate, a powerful development industry and turmoil in the state Republican Party, and what emerges is a toxic political stew.

The county is key swing territory in state and national political races. Winning Loudoun was critical to President Obama’s success in the state; Republican Ed Gillespie narrowly took the county last year and nearly unseated Sen. Mark R. Warner (D).

“What’s happening in Loudoun is very symptomatic of the tea party, the intraparty cannibalism of, ‘You’re not conservative enough,’ ” said Erika Cotti, a politically active Ashburn resident. In 20 years in Loudoun, she said, “I have never seen the buffoonery that I have seen in the past three months.”

That’s not to say odd politics are rare in sprawling Loudoun, where dense developments of townhouses and strip malls give way to rolling horse country the farther west you go.

The board has bounced back and forth between Republican and Democratic control for decades. For 15 years, one constant has been Chairman Scott K. York, who has been both a Republican and an independent as he sparred with the GOP’s conservative wing and the development interests long accused of controlling county politics.

More recently, conservative anger that has sparked internal Republican upsets throughout Virginia — notably the defeat last year of then-House Majority Leader Eric Cantor — has expressed itself in Loudoun in large part with concern over the expense of the Silver Line Metro extension.

In the Republican primary to replace York as board chairman this spring, Supervisor Shawn M. Williams, a moderate Republican, faced Charlie King, a conservative Leesburg lawyer. Williams supports the Metro extension, while King has worked for Supervisor Eugene A. Delgaudio, an anti-Metro champion and frequent foe of York and Williams.

The race took a dramatic turn earlier this year when King convened a meeting of Republicans to discuss Williams’s history of arrests for drunken driving and domestic violence, according to several people with knowledge of the gathering. As that record subsequently came to light, Williams dropped out of the race.

But York then decided he couldn’t stand to see his job go to King — who easily won the Republican primary — or two other candidates running in the general election. So he decided to run for reelection after all — but as an independent, as he did in 2004 during a previous split with the GOP.

“It’s a mess,” said one Loudoun Republican who requested anonymity to speak candidly about the party’s problems. “It’s got everybody’s head spinning.”

The extension of Metro to Loudoun is now a done deal. But what will be built around the stations now under construction remains undecided, and a review of the comprehensive plan that helped quell previous wars over development is ahead. Sequestration has put even more pressure on the county to attract new business and keep residents from revolting over bad traffic and constantly changing school boundaries.

“It’s crazy because Loudoun politics are driven almost entirely by land-use issues, but our county board is driven almost entirely by a party process system,” said former Democratic county supervisor Stevens Miller. “Those values are not driven by good answers to the questions that matter the most, so you see a lot of partisan infighting.”

Republicans have rallied around King — or tried to. At a recent “unity” news conference, more than half the board didn’t show. Asked why he was backing King, Supervisor Geary M. Higgins (R-Catoctin) struggled. “I’m on the Republican ticket,” he said.

“The problem is that we have a Republican nominee who so far has not put any points out there,” said York. “A lot of people don’t even understand why he’s bothering to run.”

Also in attendance at the event was Delgaudio (R-Sterling), an anti-gay crusader who was sued and formally censured by his fellow supervisors in 2013 over allegations that he used county resources and staff members to benefit his political campaign. Even as he sought to get back in his colleagues’ good graces, Delgaudio blasted them in newsletters.

Tension remains. At last week’s board meeting, Delgaudio repeatedly claimed that a new Metro station slated for Ashburn would be riddled with crime — to the annoyance of Ashburn Supervisor Ralph M. Buona (R).

Buona eventually invited Delgaudio to Ashburn “so you can see where it is.” The audience, which seemed to be mostly staff members and aides, gasped and laughed nervously.

Four years ago, the Democrats were so hopelessly divided that they lost every seat on the county board — and that came just four years after they had driven out four Republicans in a wave of anger over rampant development. At the time, the FBI was looking into the close ties between officials and the developers, builders and land-use lawyers.

During their brief reign, several local Democratic leaders quit the party over internal disagreements. In the 2011 elections, Miller backed a Republican and an independent over two Democrats. The board turned entirely red.

This year, Democrats say they’ve gotten their act together — even though there’s also a former Democrat running as an independent in the chairman’s race, along with King, York and the Democratic nominee.

Loudoun County Democratic Chairwoman Valerie Suzdak said the party will focus on education, in particular pushing for all-day kindergarten.

Perhaps in anticipation of that challenge, the Republican board this year decided to fully fund public schools for the first time in more than a decade. Approval of new development under this board has also been more cautious than under past Republican leadership.

“It hasn’t been autocratic, one-party rule,” said Supervisor Ken Reid (R-Leesburg).

Reid has his own theory for why Loudoun’s politics are so tumultuous: It’s too easy to get on the ballot. Only 125 signatures are needed to be a candidate in the supervisor race.

“The barrier to entry in Virginia is very low,” he said. “That’s the problem.”