A former aide to Rep. Gerry Connolly has quickly jumped into the race to replace the longtime member of Congress from Northern Virginia — with the blessing of his former boss.

James Walkinshaw, a member of the Fairfax County Board of Supervisors who served as Connolly’s chief of staff for more than a decade, cast himself as a fierce opponent of President Donald Trump’s agenda as he announced his candidacy Tuesday for the seat in the heavily Democratic suburb of Washington.

He comes with an endorsement from the retiring member of Congress, the top Democrat on the House Oversight Committee, according to an open letter that was expected to be released Wednesday. It may be influential: Connolly defeated his Republican opponent by over 33 points in 2024.

“James brings unmatched experience, a depth of knowledge about federal issues, and a steadfast commitment to progressive values,” according to the letter, which was obtained in advance by POLITICO. “When I took office in 2009, appointing him Chief of Staff was one of the best decisions I made.”

Walkinshaw, in a campaign announcement on social media, embraced Connolly’s liberal positions, including opposition to the NRA and support for abortion rights, while casting himself as an aggressive opponent of President Donald Trump sought by many activist Democrats.

“Trump is counting on us to be too scared or too complacent to fight back,” Walkinshaw said. “But I’m not backing down. Fairfax is my home, my family’s home. And I’ve been fighting for it my entire career.”

Connolly announced he would not run for reelection in late April due to the return of his esophageal cancer. In a statement, he also said he planned to step down soon from his leadership post on the oversight committee.

The announcement touched off jockeying among House Democrats looking to fill his spot on the panel. Rep. Stephen Lynch said he would pursue the post with Connolly’s backing last week. POLITICO reported Tuesday that California Rep. Robert Garcia has been making quiet moves towards a run. Also interested is Texas Rep. Jasmine Crockett.

New York Rep. Alexandria Ocasio-Cortez, defeated in a challenge against Connolly for the post last year, has ruled out a move this time.