President Joe Biden’s reelection campaign condemned Florida Governor Ron DeSantis in a clash over how the history of slavery in America is taught in his state, saying he supported the notion that an “utterly evil” system had benefits for the enslaved.

The comments by campaign co-chair Cedric Richmond followed a DeSantis tweet accusing Vice President Kamala Harris of lying about a recently adopted K-12 social studies curriculum. Harris took aim at the education standards in a speech in Jacksonville on Friday, without mentioning DeSantis by name.

DeSantis’s “comments in support of the idea that slavery had its benefits for slaves are obviously disgusting” and a sign of “extremism” among Republican presidential candidates, Richmond said in a statement Saturday.

The curriculum dispute marks the latest back-and-forth Biden and his campaign take on DeSantis, who’s positioned himself as an anti-“woke” campaigner in the 2024 election. He trails former President Donald Trump for the Republican nomination by more than 30 percentage points in the RealClearPolitics average of polls.

The debate centers on curriculum language stating that lessons include “how slaves developed skills which, in some instances, could be applied for their personal benefit.”

Harris, in a speech on the Florida board of education’s curriculum updates, said the idea that “there was some benefit” in slavery is “misleading,” false and amounts to “pushing propaganda on our children.”

DeSantis said on Twitter that Democrats such as Harris are lying “about Florida’s educational standards” to promote an opposing political vision.

That led Richmond, a former Democratic congressman from Louisiana and Biden’s campaign co-chair in 2020, to push back.

“There’s no debate over slavery,” he said. “It was utterly evil with zero redeeming qualities.”