Mark Robinson, the controversial and socially conservative Republican nominee for governor of North Carolina, made a series of inflammatory comments on a pornography website’s message board more than a decade ago,

He wished he could join the KKK, supported slavery, and bashed Martin Luther King Jr., all on an old porn website where he used to write.

Mr. Robinson, the Republican nominee for governor of North Carolina, vowed to stay in the race and sought to deny the report, which also said he had defended slavery in online posts years ago.