[Inside Mr. Dowless’s fly-by-night operation to harvest ballots in North Carolina]

Charles Ray Peterson, the Republican chairman of the county commission, noted that Mr. Dowless had previously run get-out-the-vote operations for Democrats, too. Earlier this month, the county Republican Party posted a Facebook message that accused Democrats of election chicanery: “Please just vote,” it said. “It takes a lot of Republicans to out vote all of the living, dead and illegal Democrats.”

A recent poll leaked to reporters and conducted on behalf of Mr. McCready’s campaign showed the race tied among likely voters. But a key question is whether a window of opportunity has closed for Mr. McCready, who fell short in the midterm by fewer than 1,000 votes.

The district has not elected a Democrat to the seat since 1962, and Mr. Trump won the district by more than 11 percentage points in 2016. Some Republican observers are hoping that the anti-Trump tide that allowed Democrats to retake the House in November has receded. They also feel more confident that the new nationwide message painting Democrats as out of touch has changed the narrative in their favor.

“We’re no longer talking about mean, nasty Republicans,” said Larry Shaheen, a Republican political strategist who supports Mr. Bishop. Now it’s, are we electing a socialist Democrat or a capitalist Republican?”

Mr. Bishop, 55, is well suited to the task of pressing an aggressive case against Mr. McCready and his fellow Democrats. An accomplished corporate lawyer from Charlotte, he has served in both the state House and Senate, emerging as one of the more controversial and combative members of a Republican-led Legislature that aggressively sought to give traditionally moderate North Carolina a shove to the right.

“I think I am reputed to be something of a battler in the General Assembly,” he said.

Three years ago, Mr. Bishop was the sponsor of House Bill 2. Before it was repealed, the legislation, known nationally as the “Bathroom Bill,” plunged the state into political chaos with its requirement that transgender people use restrooms in government and public buildings that correspond with the gender on their birth certificate. The furor over the bill, and the threats of corporate boycotts and canceled sports events, helped deliver a Democrat, Roy Cooper, to the governor’s mansion, but Mr. Bishop boasted of standing up to the “radical transgender agenda.”