Luke Ball, a representative for Mr. Cawthorn, said late Tuesday that the congressman had called Mr. Edwards to concede. Mr. Edwards’s narrow triumph was called by The Associated Press.

The outcome served as a rebuke of Mr. Cawthorn, a right-wing firebrand and the youngest freshman in Congress, who was once seen as a rising star of the Republican Party.

It is also a significant victory for the old guard Republicans in North Carolina and Washington who in recent months had been feuding with Mr. Cawthorn over his personal and political errors and foibles…

[P]erhaps most damaging was Mr. Cawthorn’s track record of missing important votes in Congress and his announcement last year that he would run in a new district near Charlotte, only to change his mind and return to his old district after the new district was redrawn and tilted Democratic.