MSNBC host Al Sharpton on Thursday called for moderators at the next 2020 Democrat debate to ask White House hopefuls if they have ever worn blackface.

“I think they should be asked whether they’ve used blackface,” Sharpton told TMZ. “I think they should be asked how many real black faces will they put in the White House, because we have very few now.”

The MSNBC host made the suggestion after criticizing Canadian Prime Minister Justin Trudeau’s apology for donning brownface and blackface on at least three occasions. “I think it’s insulting, I think it’s offensive,” Sharpton said of the scandal engulfing Trudeau’s election campaign.

“I think if he wanted forgiveness, he should have said that when he was running the first time. He knew then he had done it and now he says he’s done it more than once.”

“I think you can’t have different rules for different people,” he added.

The next debate, co-hosted by the New York Times and CNN, is scheduled for October 15-16 at Otterbein University in Westerville, Ohio. CNN hosts Anderson Cooper and Erin Burnett will moderate with the Times’ Marc Lacey.

Time magazine published the brownface photo on Wednesday, saying it was taken from the yearbook from the West Point Grey Academy, a private school in British Columbia where Trudeau worked as a teacher before going into politics.

It shows the then-29-year-old Trudeau at an “Arabian Nights” party in a turban and robe with dark makeup on his hands, face, and neck. Trudeau said he was dressed as a character from “Aladdin.”

“Darkening your face regardless of the context or the circumstances is always unacceptable because of the racist history of blackface,” he said. “I should have understood that then, and I never should have done it.”

West Point Grey Academy issued a statement saying the event was organized by a culturally diverse group of parent volunteers. “That said, we recognize that cultural sensitivities have evolved over the past 18 years,” it said.

Trudeau said he also once darkened his face for a performance of Harry Belafonte’s “Banana Boat Song (Day-O)” during a talent show when he was in high school.

And Canada’s Global News TV network reported a third instance, broadcasting a brief video of Trudeau in blackface while raising his hands in the air and sticking out his tongue. A Liberal Party spokeswoman said the footage was from the early 1990s.

The AP contributed to this report.