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The infamous 2019 Democratic primary debate exchange in which Vice President Kamala Harris' went after President Biden for his past position on federally-mandated school desegregation busing feels like ancient history, now that the two appear to enjoy a genuinely positive working relationship, marked by mutual respect. But an excerpt, published Tuesday by Politico, from the forthcoming book Battle for the Soul: Inside the Democrats' Campaigns to Defeat Trump by The Atlantic's Edward-Isaac Dovere suggests the on-stage back-and-forth really was a big deal.

Biden was blindsided by Harris' comments and struggled to come up with a response in the moment. When the debate went to commercial, he reportedly turned to his right and tried to score some sympathy points from then-South Bend, Indiana, Mayor Pete Buttigieg, who at the time he barely knew (Buttigieg is now his transportation secretary). "Well," Biden said, according to multiple sources familiar with the conversation, "that was some f---ing bulls---."

Meanwhile, Biden's wife, Dr. Jill Biden, who also seems to get along well with Harris and her husband Doug Emhoff these days, was particularly rankled. Dovere writes that she "couldn't bear to watch a woman who called herself a friend" of the late Beau Biden "try to tear her husband down, to score a point at a debate." During a call with close supporters the week after the debate, multiple people on the line told Dovere, Jill Biden had some harsh words for Harris. "With what he cares about, what he fights for, what he's committed to, you get up there and call him a racist without basis?," she reportedly said (Harris began her remarks by saying she didn't believe Biden was a racist). "Go f--- yourself." Read the full excerpt at Politico.