Ben Carson, a potential Republican presidential candidate, fielded calls on C-SPAN’s Washington Journal for Martin Luther King, Jr. Day to talk about the Civil Rights movement — and said that President Obama hadn’t ruined the chances of another black president because he was “half-white.

One caller in particular was a fan of Carson from what he had seen on Fox News and insisted that he “should have been the first black president.” He said, “You embody what MLK wanted for the black community. If you run for president, I’ll spread the word for people to vote for you.”

Carson thanked the caller for his praise and then said, “People say there probably won’t be another black president in our lifetime because of all the things that have happened under the first one. But my answer to that is, isn’t he half white?”

“So, that means we’re not going to have another white president either. That’s kind of a stupid argument.”