With somewhat awkward timing, former President Donald J. Trump plans to campaign in North Carolina on Saturday as his pick for governor, Lt. Gov. Mark Robinson, faces accusations of making disturbing posts on a pornographic website.

Mr. Trump’s visit to Wilmington, N.C., for a rally will take place two days after CNN reported that Mr. Robinson had once called himself a “black NAZI!” and defended slavery years ago on a pornographic forum.

Mr. Robinson, whom Mr. Trump endorsed in March, has denied the report and vowed to stay in the race. But both parties are looking closely at the fallout, which could have a spillover effect in the presidential contest, given that North Carolina is a key battleground state that Mr. Trump won twice but that Democrats see as competitive.

The lieutenant governor, who has a long history of making inflammatory and offensive remarks, is not expected to attend Mr. Trump’s rally on Saturday, according to a person familiar with the program’s details. Mr. Robinson was also absent when Mr. Trump’s running mate, Senator JD Vance of Ohio, visited the state on Wednesday, the day before CNN released its report.

A spokesman for Mr. Robinson did not immediately respond to a request for comment on Friday. The Trump campaign avoided weighing in on the controversy when asked for comment on Friday.

Democrats, who last carried North Carolina in the 2008 presidential race, are seeking to remind voters in the increasingly competitive state about Mr. Trump’s past praise for Mr. Robinson. Vice President Kamala Harris’s presidential campaign released a television ad on Friday, “Both Wrong,” highlighting Mr. Trump’s past warm words for Mr. Robinson and some of Mr. Robinson’s past polarizing statements. At least nine electronic billboards around the state will display ads on Friday and Saturday paid for by the Democratic National Committee linking the two Republicans.

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