Joe Biden is pleading for party unity after a week of harsh attacks from his presidential rivals.

“Here’s the deal — whomever the Democratic nominee is, we have to stay together,” he said at a South Carolina event on Friday night, where 20 other Dem candidates also converged.

“You all know in your gut this election is more important than any one you’ve ever been involved in,” he said in a 2-minute speech. “Not because any one of us are running, but because of the man who occupies that office.”

Biden’s campaign has been in damage-control mode since Tuesday night, when he nostalgically praised his own work with segregationist Senate Democrats in the 1970s.

“We didn’t agree on much of anything, but at least there was some civility,” Biden said of his relationship with Sen. James Eastland — adding that Eastland “never called me ‘boy,’ he always called me ‘son.'”

Sen. Cory Booker (D-New Jersey) demanded an apology from Biden for using the derogatory term once used by whites toward African-American men.

“You don’t joke about calling black men ‘boys,’” Booker said.

Biden has refused to issue a mea culpa.

Booker and the other Democratic candidates did not mention the controversy from the stage on Friday — but 21 of them were scheduled to speak Saturday at the South Carolina Democratic Party Convention.