Transcript for The backlash against Joe Biden
and Joe Biden refusing to apologize tonight after what he said about a time when congress worked stog. Biden citing segregationist senators. He said they were mean, that he didn't agree with them, but they th still worked together. His democratic opponents pouncing tonight, and Biden standing firm. Here's ABC's Cecilia Vega. Reporter: Tonight, one by one, the democratic presidential candidates are attacking Joe Biden, even as the former vice president defends himself. There's not a racist bone in my body. I've been involved in civil rights my whole career. Period. Period. Reporter: It comes after Biden talked about working with segregationist senators as an example of how he's able to do business with colleagues, even if they disagree. He mentioned Georgia's Herman Talmage. "One of the meanest guys I've ever knew. You go down the list of all these guys. Well, guess what? At least there was some civility. We got things done." And of Mississippi's James Eastland, Biden said, "He never called me boy. He always called me son." To coddle the reputations of segregationists, it's just -- it's misinformed and it's wrong. Reporter: Senator Cory booker, saying, quote, "I'm disappointed that he hasn't issued an immediate apology." Are you going to apologize? Cory booker has called for it. Apologize for what? Cory booker's called for it. Cory should apologize. He knows better. The vice president said, I should know better. And this is what I know. As a black man in America, I know the deeply harmful and hurtful usage of the world "Boy" and how it was used to dehumanize and degrade. Reporter: Other rivals pouncing, too. I don't think you have to be touting a personal relationship with people who are very brutal segregationists. It's never okay to celebrate segregationists. Never. And Cecilia Vega with us here tonight. Cecilia, Joe Biden taking serious heat here, but there are some top Democrats who have said, top piling on, this could hurt the whole party. Reporter: Exactly. Some say attacking one of their own is not a winning strategy. And one of those coming to Joe biden''s defense today, James Clyburn. He told politico, quote, you don't have to agree with people to work with them. David, we've also just learned that Joe Biden called Cory booker after those tough words that we just heard right there in our piece, the tone of that conversation, reportedly, conciliatory. All right, Cecilia, thank you. And it's you and me tomorrow
This transcript has been automatically generated and may not be 100% accurate.