Veteran Democratic pollster Cornell Belcher explained what he believes is the racist element to Arkansas Gov. Sarah Huckabee Sanders’ (R) recent swipe at vice president and Democratic nominee Kamala Harris.

Sanders, a former Trump White House press secretary, drew backlash this week for saying at a town hall event with GOP nominee Donald Trump that Harris doesn’t have anything to keep her “humble” because she doesn’t have biological children.

Belcher, talking to MSNBC’s Nicolle Wallace on Thursday, said he agreed with all the criticism that’s been leveled at Sanders and then leaned “into another dimension” of the comment which he argued was a racist dog whistle.

“Look, as a child of the south, someone who was born and raised in the south, and hearing a deeply southern governor say that word ‘humble,’ it stinks of a racial trope that I think I’m very familiar with, and the key word being ‘humble,’” said Belcher, who worked on both of former President Barack Obama’s campaigns.

“Because it’s always been about ‘you uppity Blacks’ and ‘you got to know your roots,’” he continued. It’s “a dimension that I think they’re leaning into, and they lean into constantly and Vice President Harris is an ‘uppity Black who doesn’t know her place, and she needs to be humble.’ That’s how I connect the dots on this.”

“I have put it within the context of them leaning into racial aversion and aggrievement politics, and this is absolutely a dog whistle, historical dog whistle when you’re talking about Blacks not being humble and not knowing their place,” Belcher added.

Wallace agreed it was “the through line” of what Sanders was talking about.