Fresh off a midterm election in which Democrats posted unprecedented success in Orange County, a key player behind that effort is leaving.

Fran Sdao, chairwoman of the Democratic Party of Orange County, told the group’s central committee Monday that she won’t seek re-election in January’s intraparty leadership vote. That’s because she plans to begin traveling frequently to Washington D.C., where her husband, a tax attorney, has transferred for work.

Sdao’s departure means county Democrats will have a new boss during the lead-up to the 2020 presidential election, when the party is expected to face a battle to hold four House seats they just won from Republicans. Over the next two years, local Democrats also will try to take control of the county’s Board of Supervisors for the first time in decades by flipping two GOP-held seats on that governing body.

No Democrats have immediately announced their intention to replace Sdao as local party chair. Sdao plans to remain a member of the central committee.

Sdao, a Mission Viejo political activist, won unanimous election to the chairmanship in January 2016 only days before President Donald Trump took office. As Orange County’s Democrats flocked to the Women’s March and other anti-Trump protests, Sdao worked to harness that activism toward winning local contests and flipping GOP-held House seats.

During her term, Sdao bolstered both the outreach and inner-workings of a party once relegated to second-tier status in conservative Orange County. In doing so, helped Democrats reshape the region’s political landscape.

“In two short years, our Orange County Democratic community has experienced unprecedented growth,” Sdao said Tuesday.

“We ‘flipped the House’ and elected Democrats at every level of office. My… tenure leaves our Democratic Party infrastructure stronger.”

Much of Sdao’s work was aimed at helping the party create a system that might result in long-term electoral success.

She beefed up the party’s outreach staff and implemented a new grassroots canvassing program, resulting in direct contacts with 50,000 potential Democrats in Orange County. She also hosted training sessions for first-time candidates in an attempt to build a political farm system for Democrats that might rival the model that Orange County Republicans have cultivated over decades.

Under Sdao’s watch, her party doubled the number of candidates it officially endorsed, and the number of Orange County Democratic clubs ballooned from 17 to 27.

“I am especially proud of our entire Democratic community… for tireless organizing and dedication to our values,” Sdao said.

Her tenure has come as the political bent of Orange County has shifted away from bedrock conservatism, a result of changing demographics and trends in state and national politics.

In 1990, in Orange County, Republicans held a 22-percentage point voter registration lead over Democrats. As of last month, that lead was down to 1.1 percent, according to state data. During the next two years, it’s likely that Sdao’s successor will see the moment when Democratic voters outnumber Republicans countywide.

On Monday, Fred Whitaker, chairman of the Republican Party of Orange County, issued a statement lamenting the “catastrophic” losses his party suffered locally this election cycle. He also noted that “significant numbers of Republicans we turned out, look to have voted Democrat,” and blamed the losses primarily on Democrats’ superior fundraising and ground game.

He suggested the local GOP will push to win back its dominance in Orange County.

“This isn’t the time to give up on the party but instead to work harder than before.”