RICHMOND — A Democratic newcomer will face off against a former senior aide to Republican firebrand Corey Stewart in a Jan. 5 special election, when they will compete to fill the state House of Delegates seat vacated by Jennifer D. Carroll Foy.

Carroll Foy, a Democrat from Prince William County, stepped down over the weekend to focus on her 2021 bid for governor.

In a party-run primary on Saturday, Democrats chose Candi King, an education advocate and former small-business owner, from a field of five. Heather Mitchell, who ran for the seat in this dark blue district in 2019, was the only Republican to seek that party’s nod, so there was no nominating contest. Mitchell lost to Carroll Foy, who took more than 60 percent of the vote.

The winner will have to run for reelection in November if she wants to hold the seat beyond January 2022, when Carroll Foy’s term was due to expire.

King vowed in a statement issued after her nomination to help “forge a path of recovery from this pandemic.”

“Our working families deserve to have good jobs right here in District 2, and workers that have to commute deserve convenient and affordable transportation options,” her statement said. “This pandemic has also showcased the need to explore common-sense policies like paid sick leave that make sense for workers and for their employers. This area has been hit hard by the pandemic, but I believe we can emerge better than before, with no one left behind.”

King, 38, lives in Dumfries with her husband, an Iraq War veteran and Fairfax County deputy sheriff, and their three children, including a nonverbal teenage daughter with autism. She has served as an intern for several state legislators.

Mitchell, 5o, lives in Stafford County. She was a senior aide to Stewart when he was the Republican chairman of the Prince William Board of County Supervisors, initially on his unsuccessful campaigns for governor and U.S. Senate in 2017 and 2018, respectively. She later worked in his county office. He often said he was “more Trump than Trump.”

Mitchell’s campaign noted her service to Stewart, but referred to practical suburban issues like transportation and education rather than the polarizing ones Stewart played up on the campaign trail. In an interview Monday, Mitchell said she does not share Stewart’s “very bombastic style.”

“I am my own person,” she said, noting that she focused on everyday issues like sewers and streetlights. “I am not Corey Stewart.”

Mitchell’s announcement struck a sharp tone, saying that Carroll Foy had “abandoned her constituents.” It said she would restore “sanity” to Richmond, where she accused Democrats of “working to defund our police.”

Carroll Foy stepped down to travel and raise money during the legislative session that begins Jan. 13. Legislators are prohibited from fundraising during regular sessions. She was the first of three Democrats to launch bids to succeed Gov. Ralph Northam (D), who is prohibited by the state constitution from seeking back-to-back terms.

Three other Democrats are seeking the nomination: former governor Terry McAuliffe; Lt. Gov. Justin Fairfax; and state Sen. Jennifer L. McClellan (Richmond).

On the Republican side, there are two declared candidates: state Sen. Amanda F. Chase (Chesterfield) and Del. Kirk Cox (Colonial Heights), the former speaker of the House of Delegates.

Chase, a Trump-style provocateur, recently backed off plans to run as an independent, something she vowed to do after the Republican State Central Committee voted Dec. 5 to choose its nominee at a convention instead of in a statewide primary.