Former Vice President and 2020 Democratic frontrunner Joe Biden was defiant Wednesday despite criticism over comments at a fundraiser about his relationship with James Eastland, a Mississippi senator and noted segregationist. "Apologize for what? Cory [Booker] should apologize to me," Biden said, referring to fellow presidential contender Booker, who said earlier he was "disappointed" Biden didn't apologize.

At a fundraiser in New York City on Tuesday, Biden had referenced Eastland, who served in the Senate from 1943 to 1978 and died in 1986, while arguing for more civility in Washington.

"I know the new, new left tells me that I'm — this is old-fashioned," Biden said, according to the pool report. "Well guess what? If we can't reach a consensus in our system, what happens? It encourages and demands the abuse of power by a president. That's what it does. You have to be able to reach consensus under our system — our constitutional system of separation of powers."

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Biden then turned to his own lengthy career in the Senate, where he represented Delaware from 1973 to 2009.

"I was in a caucus with James O. Eastland," he told the crowd. "He never called me boy, he always called me son."

Biden said Wednesday "the point I'm making is you don't have to agree. You don't have to like the people in terms of their views but you just simply make the case and you beat them."

When asked if he should apologize, Biden insisted Booker should apologize because "he knows better ... there's not a racist bone in my body."

And at a fundraiser at Tim Shriver's home on Wednesday, Biden said he and Shriver's uncle, the late Sen. Ted Kennedy, "put up with the likes of like Jim Eastland and Hermy Talmadge and all those segregationists and all of that."

"And the fact of the matter is that we were able to do it because we were able to win-- we were able to beat them on everything they stood for," Biden said.

Eastland, the influential chair of the Senate Judiciary Committee, was the longest-serving Democrat in the chamber when Biden arrived in Washington. He was also one of the civil rights movement's most militant opponents in Congress and an avowed white supremacist. Earlier this year, CNN reported that Biden had sought and received Eastland's support for legislation aimed at stopping the busing of students between schools to increase diversity.

In his remarks Tuesday, Biden also referenced the segregationist Georgia Sen. Herman Talmadge, another Democrat, whom he called "one of the meanest guys I ever knew," before praising a bygone era of comity.

"At least there was some civility," Biden said. "We got things done. We didn't agree on much of anything. We got things done. We got it finished. But today, you look at the other side and you're the enemy. Not the opposition, the enemy. We don't talk to each other anymore."

Biden's primary opponents were quick to attack him Wednesday. After Biden said Booker should apologize to him, Booker said he was "raised to speak truth to power" and he will "never apologize for that."

Booker acknowledged "we all say things we regret or didn't come out right," but said "I don't know why he needs this lesson" why he should not have made those comments.

"He should have the sensitivity to know this is time to be an ally, to be a healer," Booker said.

In his statement earlier Wednesday, Booker said "you don't joke about calling black men 'boys.' Men like James O. Eastland used words like that, and the racist policies that accompanied them, to perpetuate white supremacy and strip black Americans of our very humanity."

He went on to say that Biden's "relationships with proud segregationists are not the model for how we make America a safer and more inclusive place for black people and for everyone. I have to tell Vice President Biden, as someone I respect, that he is wrong for using his relationships with Eastland and Talmadge as examples of how to bring our country together."

He also called upon Biden to apologize for the comments.

Later Wednesday, Sens. Elizabeth Warren, Kamala Harris and Bernie Sanders commented on Biden's remarks.

"I'm not here to criticize other Democrats but it's never ok to celebrate segregationists. Never," Warren said on Capitol Hill. Harris told reporters that Biden's remark "concerns me deeply. If those men had their way I would not be in the United States Senate and on this elevator right now." Sanders reiterated Booker's call for an apology:

I agree with Cory Booker. This is especially true at a time when the Trump administration is trying to divide us up with its racist appeals. https://t.co/VyVcG6srQM — Bernie Sanders (@BernieSanders) June 19, 2019

Mayor Bill de Blasio, who's currently polling near the bottom of the two dozen candidates running for president, posted a tweet with a photo of his biracial family.

"It's 2019 & @JoeBiden is longing for the good old days of 'civility' typified by James Eastland. Eastland thought my multiracial family should be illegal & that whites were entitled to 'the pursuit of dead n*ggers,'" the New York mayor wrote. "It's past time for apologies or evolution from @JoeBiden. He repeatedly demonstrates that he is out of step with the values of the modern Democratic Party."

However, it's not clear that the quote he attributes to Eastland was in fact uttered by the Mississippi senator. Martin Luther King, Jr. biographer Stephen Oates pointed out that although several people, including noted Lyndon Johnson biographer Robert Caro, mistakenly claimed that Eastland had said these words, the statement was in fact "printed on a handbill circulated" at an Eastland rally.

The criticism from Biden's rivals prompted Symone Sanders, a senior adviser on the campaign, to issued a five-part defense of his remarks on Twitter Wednesday afternoon.

"@JoeBiden did not praise a segregationist. That is a disingenuous take. He basically said sometimes in Congress, one has to work with terrible or down right racist folks to get things done. And then went on to say when you can't work with them, work around them," Sanders said. She added that Biden "has been an ally in the fight for civil rights for years."

.@JoeBiden did not praise a segregationist. That is a disingenuous take. He basically said sometimes in Congress, one has to work with terrible or down right racist folks to get things done. And then went on to say when you can't work with them, work around them. — Symone D. Sanders (@SymoneDSanders) June 19, 2019

Biden's comments were also criticized by some political observers. "There is no punchline here, no emoji or funny meme to soften the harm of your words," Connie Schultz, a journalist and the wife of Ohio Democratic Sen. Sherrod Brown, tweeted. "That segregationist never called you 'boy' because you are white. If you want to boast about your relationship with a racist, you are not who we need to succeed the racist in the White House."

While Talmadge and Eastland, like Biden, were Democrats, they were more aligned with Dixiecrats, the lawmakers from the Deep South who opposed civil rights. Northeastern and Western Democrats in the late 19th century were more aligned with moderate Northeastern Republicans, and it was this coalition that passed civil rights legislation in the 1960s.

Bo Erickson, Zachary Hudak and Alan He contributed to this report.