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 general election chances.

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’s still 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.