Congresswoman Nancy Mace, who is running for governor of South Carolina, has lost one of her most well-known in-state consultants over her ties to Senator Rand Paul and Congressman Thomas Massie — both of whom have been attacked by President Trump over policy disagreements.

Ms. Mace is facing off against a number of well-known elected Republicans, and the consultant who has now left her campaign says Mr. Trump should choose someone else to endorse ahead of the primary. 

Ms. Mace was elected to Congress in 2020 as a kind of socially liberal moderate from the Low County and Charleston suburbs of South Carolina, though she has moved significantly to the right in recent years. She has broken with Republican leadership in the House, including by voting to oust Speaker Kevin McCarthy and sign on to a petition to force a release of the Epstein files despite Speaker Mike Johnson’s opposition. 

Her campaign for governor has relied on the perception of her as an outsider, both on Capitol Hill and, hopefully, as the state’s future governor. On Monday, however, one of her top consultants resigned over her ties to anti-Trump elements in the party. 

“Nancy Mace has yet again decided to turn her back on MAGA to hug the political cactus that is the Rand Paul and Thomas Massie wing of the Party,” J. Austin McCubbin said in a post on X. Mr. McCubbin managed Ms. Mace’s 2022 congressional campaign, served as a top political staffer at the Republican National Committee, and ran Mr. Trump 2024 South Carolina primary operation. 

“I have notified her and her team that I am resigning because of this,” Mr. McCubbin said. He joined Ms. Mace’s gubernatorial campaign earlier this year. 

Ms. Mace’s campaign did not immediately respond to a request for comment. 

Mr. Trump has been viciously going after Messrs. Massie and Paul for months as the two Kentucky libertarians have opposed him on key policy issues. Both men voted against the One Big Beautiful Bill Act over the summer, citing the debt spending that would come about as a result of the legislation. 

Mr. Paul has been attacking Mr. Trump for his strikes on alleged drug boats in the Caribbean and the eastern Pacific, saying that the president cannot unilaterally declare war. He has said the president and the U.S. military may be guilty of committing extrajudicial murders of people who may not even be smugglers. Mr. Massie also tried to curb Mr. Trump’s war powers after the president ordered that Iran’s nuclear capability be destroyed earlier this year. 

Mr. McCubbin says that Ms. Mace winning the support of these two men is enough for him — and possibly the president — to stay as far away from Ms. Mace as possible. 

“Earlier this year Nancy parted ways with her General Consultant, because he was openly criticizing the President’s Iran strike and siding with Thomas Massie,” Mr. McCubbin wrote on X. “Last month the Rand Paul-affiliated Protect Freedom PAC began spending money on Nancy’s behalf.”

“When I talked to Nancy last Wednesday, it became clear she has fully embraced the Rand Paul PAC. She told me she is directing a personal friend to fund a 7-figure check to Rand’s PAC,” Mr. McCubbin added. 

“Nancy Mace is wittingly or unwittingly a proxy for Rand Paul’s 2028 presidential campaign. That’s the straw that broke the camel’s back,” he wrote further. 

Ms. Mace is running in the primary against a fellow House lawmaker, Congressman Ralph Norman, state attorney general Alan Wilson, and lieutenant governor Pamela Evette, among others. The most recent polling shows no candidate above 20 percent in the primary, though Ms. Mace and Ms. Evette are currently leading the field in a statistical tie. 

In his resignation announcement, Mr. McCubbin says he tried to explain to Ms. Mace the perils of aligning herself with Mr. Trump’s chief Republican foes in Congress. “She wouldn’t hear it when I warned her about the political risks and offered alternative solutions. She accused me of mansplaining, a woke term used by people who hate men, who ironically are her best demographic,” Mr. McCubbin wrote Monday. 

“Anyone who knows me knows that I have nothing personally against Rand or Nancy. This is about loyalty,” he added. 

Because South Carolina is a deep-red state, the only real election for governor will be in the Republican primary. Mr. McCubbin says that race is about one thing and one thing only: Mr. Trump’s endorsement. 

On Monday, Mr. McCubbin urged Mr. Trump’s team to do one thing when considering an endorsement for the race, whether it be for Ms. Mace or for someone else.

“Scratch her name from the list,” Mr. McCubbin wrote.