By James Oliphant

(Reuters) - Republican presidential candidate Donald Trump will not be joined by his party's embattled pick for North Carolina governor when he visits the critical electoral state on Saturday, the Trump campaign said.

Trump previously endorsed Mark Robinson, who was the subject of an explosive CNN report this week that he once called himself a Black Nazi and proposed bringing back slavery in comments posted on a pornography website. 

Robinson, the state's lieutenant governor, denied the allegations and has said he will remain in the governor’s race. His campaign could not be reached for comment.

Some Republicans fear his candidacy in one of the country's highest-profile down-ballot races this year could damage Trump’s chances in the battleground state, where polls show Trump essentially tied with Democratic rival Kamala Harris ahead of the Nov. 5 election.

Ahead of Trump's afternoon rally in Wilmington, North Carolina on Saturday, the Democratic National Committee launched new advertising across the cities of Raleigh, Charlotte and Greensboro tying the former president to Robinson. 

The billboard ads show a photo of the two men together, along with direct quotes from Trump previously calling Robinson an "outstanding person" and an "incredible gentleman." 

The Harris campaign also began running a TV ad in the state on Friday featuring Trump’s past praise for Robinson.  

In March, Trump called Robinson “Martin Luther King on steroids” after Robinson delivered remarks in Greensboro, and Robinson appeared at a Trump event as recently as last month. Robinson would be the state’s first Black governor if elected.  

Robinson has a history of inflammatory rhetoric, at times referring to Muslims as “invaders” and calling gay and transgender people “filth.” He has made comments denying the Holocaust. 

Trump has yet to address the latest allegations against Robinson. One Trump adviser, who asked not to be named, said Trump should stay silent and not fan the controversy.

"Ignore it, and let it die," the adviser said.

Trump's campaign did not respond to a request for comment.

Harris’ campaign and its allies have made a significant investment in North Carolina, including two stops by the vice president last week. A Democratic presidential candidate has not won the state since 2008, but voters elected Democrat Roy Cooper as governor in 2016 and 2020. 

Robinson had been trailing his opponent, Democrat Josh Stein, even before the CNN report, suggesting that he could be a drag on Trump’s chances in the state if some disaffected Republicans stay home on Election Day or defect to Harris. 

Chris Cooper, a professor of political science at Western Carolina University, said in a state that Trump won by just 1.3 percentage points in 2020, the Robinson scandal could damage Republicans' chances up and down the ballot in November, including Trump's. 

"If some people feel that the Republican brand is stained enough that they'd rather stay home, then that's going to matter," Cooper said. "It doesn't take a big difference to flip the state."

Thom Tillis, a Republican U.S. senator from North Carolina, responded to the allegations against Robinson by telling voters on X that “we must focus on the races we can win,” citing the presidential contest but omitting the gubernatorial vote.

“If Harris takes NC, she takes the White House,” Tillis wrote. “We can’t let that happen.” 

(Reporting by James Oliphant. Additional reporting by Stephanie Kelly, Tim Reid and Gram Slattery; Editing by Colleen Jenkins and Rod Nickel)