House Republicans Tire of Madison Cawthorn’s Antics. Some in His District Have, Too.

Mr. Cawthorn has the advantage of broad name recognition in a field of challengers who, with a couple of exceptions, have raised little money needed to become better known. He also has the endorsement of Mr. Trump, whom Mr. Cawthorn identified on Saturday as “a man who mentors me.”

An internal poll of likely Republican voters this month for a Cawthorn rival showed the congressman leading the field with 52 percent and 17 percent undecided. “Cawthorn is right on the bubble of the 50 percent mark; incumbents who slip below that during the campaign are in danger,’’ wrote Glen Bolger, a top Republican pollster who conducted the poll.

Mr. Cawthorn did himself no favors last year when he announced he would run in a new district near Charlotte, the state’s largest city. Political insiders speculated that he sought a higher profile in a major media market ahead of an eventual statewide run. But then legal challenges led to a redrawn state congressional map, and Mr. Cawthorn’s planned new district tilted Democratic. So he returned home to his old district, where viable contenders had joined the race in his absence.

“Had he not flirted with another district, he wouldn’t be in this situation, where there’s a question of whether he’ll win this primary,’’ said Christopher Cooper, a political scientist at Western Carolina University in Cullowhee, N.C. “It’s the thing that opened the door for the field to expand.”

It’s unclear if Mr. Cawthorn’s temporary desertion has penetrated to average voters, even if it angers party officials. “I believe he probably has lost most of the local-level Republican movers and shakers,’’ said David Baker, a voter who attended a recent Republican convention in Jackson County.

But Mr. Baker, an employee benefits expert, said rank-and-file Republicans like himself still support Mr. Cawthorn because of his “clarity on those issues that were so important to Trump.”

Mr. Cawthorn was raised in Hendersonville, N.C., a small community where he was home-schooled. His meteoric rise began with his defeat of a primary candidate handpicked to fill the seat held by former Representative Mark Meadows, who was appointed Mr. Trump’s White House chief of staff.