Tillis sides firmly with Trump: “Would I have done it? I don’t know because I’m not the president, and I haven’t been pursued relentlessly for three years.”

Trump “deserves to be defended” by Republicans ahead of a likely impeachment trial, Tillis added. The Democrats’ evidence thus far? “Nothing there,” he tells supporters.

It’s a shrewd political strategy amid a well-funded primary challenge from Garland Tucker, a conservative businessman who paints Tillis as an enemy of the Trump agenda. But Tillis’ role as Trump’s new best friend threatens to undermine his profile as a diligent, unpredictable senator — and could damage his chances in the general election.

Standing behind Tucker is potential Democratic opponent Cal Cunningham, an establishment-backed military veteran eager to cast Tillis as a lackey who “married himself to Donald Trump.” Trump won North Carolina in 2016, but it is a perennial swing state, and Trump’s approval ratings are sinking.

Most immediate, however, is surviving perhaps the toughest primary battle facing any Republican senator this cycle.

“He probably has more of a challenge in a primary than he does in a general,” said Rep. Mark Meadows (R-N.C.), a close ally of the president who has not endorsed Tillis.

Meadows added that Tillis’ support for the special counsel bill and his shifting stance on the national emergency declaration “created an opening in a race that would generally not have seen a credible primary challenger.”

The wealthy Tucker is spending heavily on ads highlighting Tillis’ “flip-flop” on the border — Tillis’ most infamous episode as a senator — when he voted to uphold the national emergency after announcing his opposition in a Washington Post op-ed. Tillis boasts a 94 percent voting score with the president, but Tucker is pouring enough money into pointing out Tillis’ perceived dalliances away from Trump that the senator felt compelled to respond with an ad barrage of his own.

Tillis acknowledges his style isn’t necessarily built to appeal to his party’s hard-liners. At a North Carolina Federation of Republican Women event, he lamented that sometimes he gets “criticized because I don’t speak too fiery or talk too angry.”

“Some people, I think, perceive my style as being something that’s soft,” he said during a 25-minute interview at the state party headquarters. “But I’ve got a good conservative track record to run on. And we believe if people know it, they know where I stand on immigration, they know where I stand to the level where the president will endorse me. We’ll win.”

These are rare moments of self-reflection for Tillis, a confident, bordering on cocky, 59-year-old former state House speaker who helped rebuild the North Carolina GOP. He said Trump would campaign for him in the primary if necessary but dismisses Tucker: “I don’t believe the race is even close.”

Many Republicans still believe Tillis can ride Trump’s coattails to reelection, though he risks running behind the president in a state known for close elections. GOP alarms go off every few years in North Carolina, sometimes warranted and sometimes not: In 2016, GOP Sen. Richard Burr was easily reelected despite running a laid-back campaign, while the Republican governor was cast out.

This year, Tucker is essentially operating as a Democratic super PAC, draining Tillis of resources and allowing national Democrats to sit back and enjoy the show. It’s a situation that most other vulnerable incumbents have avoided, but Tillis’ plight is unique, having riled up parts of Trump’s base with his limited dissent.

Rep. Mark Walker (R-N.C.) flirted with running against Tillis, but backed down. And while Meadows said he is not interested, he noted that with the state’s congressional districts in flux, “you could get a sitting member of Congress thinking it’s easier to run for Senate” than run for reelection in a blue district.

Walker and Rep. George Holding (R-N.C.) have both been drawn into Democratic areas in the latest map. The deadline to jump into the primary is Dec. 20.