Rep. Nancy Mace’s former top staffer is gunning to steal her seat.

Dan Hanlon, who was Mace’s chief of staff in Washington until December, has been making moves to challenge Mace in the Republican primary for her South Carolina seat, first reported by Politico.

A source familiar with the emerging race told Breitbart News “The feedback Hanlon has received is overwhelmingly positive, both among the donor class and grassroots voters, and people across the district are asking for any way they can get involved to defeat Mace, citing her chaotic style and unwillingness to make difficult decisions, such as whether to endorse Donald Trump or Nikki Haley.”

Hanlon and Mace had a falling out after Mace voted to take the speaker’s gavel from Rep. Kevin McCarthy.

McCarthy has since resigned from Congress, but he sits on an enormous war chest and reportedly is seeking retribution against the eight Republicans who voted with all Democrats to remove him.

UNITED STATES – MARCH 18: House Minority Leader Kevin McCarthy, R-Calif., conducts his weekly news conference in the U.S. Capitol Visitor Center on Friday, March 18, 2022. (Tom Williams/CQ-Roll Call, Inc via Getty Images)

He has specifically said Mace does not deserve to keep her seat.

“If you’ve watched her, just her philosophy, and the flip-flopping, I don’t believe she wins reelection,” McCarthy told CNN after his ouster as Speaker.

McCarthy accused Mace of lying about him breaking promises to her – her stated justification for voting to remove him. Without naming Hanlon, McCarthy relayed a conversation between the two as evidence of Mace’s fabrications.

“So, I call her chief of staff … I said, ‘Can you please tell me, I don’t understand. Where have I not kept my word?’” McCarthy explained. “[Her] chief of staff said, ‘You have kept your word 100 percent.’”

The source tells Breitbart that McCarthy “likes Dan very much” and “wants nothing more than to end Nancy.”

Mace has suffered enormous staff turnover during her tenure in Congress, with former staffers openly taking to social media to accuse her of running a dysfunctional office focused on self-promotion.

Former staffers have also spoken with left-leaning media attacking Mace and her operation.

Hanlon was along for the ride, and undoubtedly possesses knowledge that could prove damaging to Mace in a primary.

Before his stint with Mace, Hanlon served four years in the Trump administration.

The deadline to qualify for the race is March 30.

Bradley Jaye is a Capitol Hill Correspondent for Breitbart News. Follow him on X/Twitter at @BradleyAJaye.