Rep. Alexandria Ocasio-Cortez said Thursday that Sen. Cory Booker (D-NJ) need not apologize for criticizing Vice President Joe Biden for praising the “civility” of Segregationists.

“For the record, Cory Booker does *not* owe Joe Biden an apology for pointing out that waxing nostalgic about working with segregationists is insensitive,” Ocasio-Cortez wrote on Twitter. “‘He knows better?’ Really? What is ‘better?’ To stay quiet about it?”

At a New York fundraiser Tuesday, Biden pointed to two segregationist senators, James Eastland (D-MS) and Herman Talmadge (D-GA), to argue that Washington functioned more smoothly a generation ago than under today’s “broken” hyperpartisanship.

“We didn’t agree on much of anything,” Biden said of the two men, adding that Talmadge was “one of the meanest guys [he] ever knew” and that Eastland called him “son,” though not “boy,” a reference to the racist way many whites addressed black men at the time.

Yet even in that Senate, Biden said, “At least there was some civility. We got things done.”

The former vice president’s rivals for the 2020 nomination, including the two major black candidates in the race, Sens. Cory Booker (D-NJ) and Kamala Harris (D-CA), roundly criticized Biden’s comments. Yet, Biden did not back down Wednesday and was particularly defiant in the face of criticism from Booker, who said the former vice president should apologize.

In response, Biden said Booker should apologize because the senator “should know better” than to question Biden’s commitment to civil rights.

“There’s not a racist bone in my body,” Biden said. “I’ve been involved in civil rights my whole career.”

Ocasio-Cortez’s defense of Booker came after she slammed Biden for touting his past working relationship with segregationists in an interview.

“If you ignore racism and if you don’t address issues of race with racists, then everything is fine, right?” Ocasio-Cortez told Politico on Wednesday. “That’s how you work with segregationists: By not confronting the racism and their institutionalization of second-class citizenship and a lack of fully recognizing African Americans.”

Amid an outcry from White House hopefuls and progressives on Capitol Hill, House Speaker Nancy Pelosi (D-CA) did not condemn Biden, and instead, praised him as genuine.

During her weekly briefing, Pelosi said:

I think that authenticity is the most important characteristic that candidates have to convey to the American people, and Joe Biden is authentic. He has lived his life, he considers certain things a resource, that he has worked across the aisle, that’s what he was saying. That’s not what this election is about. … This election is about how we connect with the American people, addressing their kitchen table needs. For us to spend time on an issue like this, which is important, but it’s not central to what the election is about, what the election is about is the financial stability and well-being of Americans working families.

The controversy is becoming one of the most intense disputes of the primary, showing the hazards for Biden as he tries to turn his decades of Washington experience into an advantage. Instead, he is infuriating Democrats who say he is out of step with the diverse party of the 21st century and potentially undermining his argument that he is the most electable candidate to take on President Donald Trump.

The Associated Press contributed to this report.