After Biden’s poor debate performance, Democratic leaders have firmly rejected calls to choose a younger candidate for the Nov. 5 election. Meanwhile, Biden, 81, also discussed the issue with family members at the presidential retreat at Camp David on June 30.

The New York Times, citing people familiar with the situation, reported that Mr. Biden’s family is urging him to stay in the race and fight on. Some members of his family have expressed frustration with the way his staff prepared for the May 27 debate.

Calls for Biden to drop out have continued to grow since May 27. A CBS poll after the debate found that the number of Democrats who believe Biden should not run increased by 10 percentage points, from 36% in February to 46%.

"The unfortunate truth is that Mr. Biden should withdraw from the race for the good of the country... Retirement is now necessary for President Biden," the Atlanta Journal-Constitution said in an editorial on June 30.

Democratic leaders have dismissed this. Georgia Democratic Senator Raphael Warnock, one of the Democrats considered a possible Biden replacement, responded: "Absolutely not. I support Joe Biden, and it is our job to make sure he gets there in November."

House Democratic leader Hakeem Jeffries, who could become speaker next year if his party can take control of the House in November, acknowledged that Mr Biden had suffered a defeat, but that it was “just preparation for a comeback”.

Senator Chris Coons, a leading surrogate for Mr Biden, said Mr Biden needed to stay in the race to defeat Mr Trump. "I think he's the only Democrat who can beat Donald Trump."

Although Democratic leaders have expressed no desire to replace Mr. Biden, it is still up to the US President to decide whether he wants to end his re-election bid.

Representative Jamie Raskin, a prominent Democrat in Congress, said there were “very honest and serious” conversations going on within the party. “Whether he’s the nominee or someone else is the nominee, he’s going to be the keynote speaker at our convention. He’s going to be the person we rally around moving forward,” he said.

Earlier in the debate with former President Donald Trump on June 27, Mr. Biden, with a hoarse voice, gave a shaky, hesitant performance, in which he stammered several times. Some Democrats said this performance could be a factor in his elimination.

Hoai Phuong (according to Reuters)