On Wednesday, some Democrats who had privately called on him to quit the race reversed themselves in public, as the Congressional Black Caucus and Left-wing congresswoman Alexandria Ocasio-Cortez weighed in behind the president.
Many House Democrats appeared resigned to him remaining on the ticket after a meeting in which they privately discussed concerns over his candidacy.
The former speaker’s intervention is likely to reinvigorate efforts to persuade Mr Biden to stand aside for a younger replacement, after a disastrous debate performance against Donald Trump in which he repeatedly lost his train of thought.
Mrs Pelosi, 84, said that the president and his party should focus on the Nato conference this week before coming to a decision on Mr Biden’s future.
The president is due to hold a press conference on Thursday evening in which his responses will be closely monitored for the slurring and moments of confusion that punctuated the debate.
Hold off
“Let’s just hold off,” Mrs Pelosi urged on MSNBC, adding: “Whatever you’re thinking, either tell somebody privately, but you don’t have to put that out on the table until we see how we go this week.”
Nate Silver, the prominent analyst and pollster, said that Mrs Pelosi’s remarks on “Biden’s favourite show” were “as close as possible to saying he should drop out without saying it outright”, noting that the odds promptly jumped on Mr Biden quitting the race.
Mrs Pelosi is often cited as one of few key Democrats who could influence Mr Biden’s decision-making, alongside the Obamas and his close family.
It came after Senator Michael Bennet (D-CO) warned Republicans could take the White House, the House and the Senate in a “landslide” win if Mr Biden stayed in the race.
Electing Donald Trump again
“It’s critically important for us to come to grips with what we face, if together, we put this country on the path of electing Donald Trump again,” he told CNN.
On Thursday, Congressman Ritchie Torres (D-NY) said that Democrats needed to consider the “down-ballot effect of whomever we nominate”.
“Blindness is not bliss,” he said, “amid the terrifying threat of a Trump presidency.”
Mr Biden’s presence on the ballot could turn New York into a “battleground” state, data shows.
‘New York is now a battleground state’
The president’s lead in the state, which he carried by 23 points in 2020, has narrowed to just 8.9 per cent, according to polling aggregator FiveThirtyEight.
Mark Levine, the Democratic leader of Manhattan borough, told Politico that while New York had been deep blue for decades, the data made him “truly believe we’re a battleground state now”.
Nationally, Mr Biden’s support has dropped from around 47 per cent on June 27, the day of the presidential debate, to 44 per cent, in what the Cook Political Report termed the most dramatic “polling shift of the year”.
Congressman LLoyd Doggett (D-TX), the first Democrat to call on Mr Biden to stand down, said that the former speaker’s comments were “keeping the situation very open, very fluid”.
“I don’t think it moves members, but I think it compromises the goal to solidify support for Biden/move forward,” a senior Democratic aide told the news website Semafor.
In the immediate aftermath of the debate, Mrs Pelosi said it was a “legitimate question” to ask if Mr Biden had a “condition” that caused his stuttering performance.