Sen. Cory Booker, D-N.J., expressed solidarity with former Housing and Urban Development Secretary Julián Castro for his controversial attack against former Vice President and 2020 frontrunner Joe Biden.

"I think we are at a tough point right now, because there’s a lot of people concerned about Joe Biden’s ability to carry the ball all the way across the end line without fumbling," Booker said when asked about Castro's remarks following the debate. "And I think that Castro had really legitimate concerns about can he be someone in a long grueling campaign… and has every right to call out.”

"Do you think that Biden did a better job tonight?" CNN anchor Erin Burnett asked. "Do you think that he showed that he could take the ball over the line?"

"I think there were a lot of moments where a number of us were looking on the stage when he tends to go on sometimes," Booker responded. "At one point, he was talking about communities like mine listening to record players. I don't remember the last time I saw a record player... But there are definitely moments where you listen to Joe Biden and you just wonder...”

BIDEN MOCKED FOR ENCOURAGING KIDS TO LISTEN TO 'THE RECORD PLAYER' AT DEBATE

"Senator, are you saying that he's just too old to be president?" CNN chief political correspondent Dana Bash reacted.

"No, I'm definitely not saying that because I've listened to Joe Biden over the years and often felt like there were times that he is going on or meandering in his speech," Booker said. "I want someone that can excite and energize and call us to a campaign like we saw back in '08, in '12 where we saw record turnouts and somebody that can speak to the fullness of the Democratic Party. If I believed Joe Biden was that person, I wouldn't be sitting here."

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During a fiery exchange, Castro took a shot at Biden’s memory, accusing him of contradicting himself about whether Americans would have to buy into a public health care option under his plan or if they would be automatically enrolled.

“I can’t believe that you said two minutes ago that they had to buy in, and now you’re saying they don’t have to buy in,” Castro said. “You’re forgetting that!”