In his first interview since leaving the White House, President Biden said it “wouldn’t have mattered” if he had dropped out of the 2024 campaign earlier.

In a wide-ranging interview with BBC Radio 4, Mr. Biden made the admission after being asked by journalist Nick Robinson for his thoughts on his decision to pull himself out of contention just four months before Election Day.

“Did you leave too late? Should you have withdrawn earlier? Given someone else a chance?” Mr. Robinson asked.

“I don’t think it would have mattered. We left at a time when we had a good candidate,” Mr. Biden said, referring to Vice President Harris. “She was fully funded.”

Mr. Biden also explained why he believes it would have been the wrong move to leave the race any sooner. “What we had set out to do, no one thought we could do and [we had] become so successful with our agenda, it was hard to say, ‘I’m going to stop now,’” he said.

“I meant what I said when I started. I think I’m prepared to hand this to the next generation, the transition government, but things moved so quickly that it made it difficult to walk away,” Mr. Biden said.

The former president also took the opportunity to go after his successor, saying that President Trump’s conduct since returning to the White House was “beneath” the presidency.

During the interview, Mr. Biden called out Mr. Trump for his desire to make Canada the 51st state, take control of the Panama Canal and Greenland, as well as rename the Gulf of Mexico to the Gulf of America.

“What the hell’s going on here? What president ever talks like that? That’s not who we are,” Mr. Biden said. “We’re about freedom, democracy, opportunity, not about confiscation.”

He also took issue with the contentious Oval Office meeting with Vice President Vance and President Zelensky in February.

“I found it sort of beneath America in the way that took place,” he said, adding that a peace deal brokered by America would be a “modern-day appeasement” since Ukraine would have to give up occupied land to Russia.

“Europe is going to lose confidence in the certainty of America and the leadership of America,” Mr. Biden said. “Other nations will be left wondering, ‘Well, what do I do now? Can I rely on the United States? Are they going to be there?’”