The publication writes that the problem is Biden's unconvincing performance during the debate, his regular reservations, weak voice, and inability to articulate his party's position on major issues.

"Parties exist to win. A man who was on stage with Trump can't win. Fear of Trump suppressed criticism of Biden. Now that same fear will fuel calls for his removal as a candidate", a senior Biden staff official said.

A group of House Democrats said they watched the debate together, and one, who spoke on condition of anonymity, acknowledged it was a "disaster" for Biden. The spokesman said the panel was discussing the need for a new presidential nominee.

Mark Buell, a prominent donor to Biden and the Democratic Party, said after the debate that the president should seriously consider whether he was the best person for the nomination. "Do we have time to put someone else in there?"

He added that he's not calling for Biden to step aside just yet, but "the Democratic leadership has an obligation to go to the White House and clearly show what America thinks because democracy is at stake here, and we're all nervous".

California Governor Gavin Newsom, one of those mentioned as a possible replacement for Biden besides Vice President Kamala Harris, brushed off talk of switching candidates.

"I would never turn my back on President Biden's record. I would never turn my back on President Biden, and I don't know any Democrat in my party who would do that, especially after tonight", he told reporters after the debate.

Andrew Young, who is running in the 2020 Democratic primary, wrote in X even before the debate ended, "Guys, the Democrats should nominate someone else — before it's too late".

Some Democrats say it's too late, noting that Biden is a proud, stubborn man who has long insisted that he is best equipped to defeat Trump and won't listen to anyone but perhaps his wife, Jill Biden.

• According to a CNN poll, after the debate between Joe Biden and Donald Trump, 5% of observers changed their minds about whom to vote for.
  Trump was named the winner of the debate by 67% of viewers, Biden by 33%.