US President Joe Biden speaks as he meets with national union leaders at the American Federation of Labor and Congress of Industrial Organizations (AFL-CIO)  headquarters in Washington, DC, on July 10, 2024.
US President Joe Biden speaks as he meets with national union leaders at the American Federation of Labor and Congress of Industrial Organizations (AFL-CIO) headquarters in Washington, DC, on July 10, 2024. AFP

A Democratic senator on Wednesday called on US President Joe Biden to ditch his reelection bid, capping a brutal day that saw mounting pressure from high-profile actor and donor George Clooney and party heavyweight Nancy Pelosi.

As the 81-year-old tried to show his leadership credentials at a NATO summit in Washington, domestic calls have been growing for Biden to quit following his disastrous debate performance against Republican challenger Donald Trump.

At least eight House Democrats have openly called on Biden to not seek reelection, but Peter Welch became the first in the Senate to explicitly do so as concerns rise over his age and fitness.

"For the good of the country, I'm calling on President Biden to withdraw from the race," the Vermont senator said in an opinion piece in the Washington Post.

News outlet Axios reported Wednesday that Senate Majority Leader Chuck Schumer had also privately signaled to donors that he was open to replacing Biden on the Democratic ticket.

However, in a statement shared by his office Wednesday evening, Schumer said "I support President Biden and remain committed to ensuring Donald Trump is defeated in November."

Biden has been trying to stem a growing tide of Democrats saying that he cannot win in November, but a steady drip of public revolt is squashing efforts to turn the page on the crisis.

Hollywood star Clooney penned a devastating editorial in the New York Times Wednesday just three weeks after co-hosting a huge fundraiser in Los Angeles that raised nearly $30 million for Biden.

"It's devastating to say it, but the Joe Biden I was with three weeks ago at the fundraiser was not the Joe 'big F-ing deal' Biden of 2010," wrote Clooney.

"He wasn't even the Joe Biden of 2020. He was the same man we all witnessed at the debate."

Clooney said that Biden would lose the presidential election, and Democrats would also lose both chambers of Congress.

In response to Clooney's editorial, the Biden campaign pointed to the president's statements on Monday saying he was committed to running again in November.

Biden has blamed jet lag and a cold for his performance in the June 27 television debate with Trump.

Media-shy for much of his presidency, he will also give a fresh interview to broadcaster NBC on Monday as he seeks to convince voters.

Former House speaker Pelosi, 86, was lukewarm on his candidacy Wednesday, telling MSNBC "it's up to the president to decide if he is going to run."

"We're all encouraging him to make that decision because the time is running short," she said, despite Biden's repeated pledges last week to stay in the race.

Pelosi said Biden should delay any final decision until after NATO's 75th anniversary summit in Washington, which ends on Thursday with what will be a closely watched press conference by the president.

Trump, who has been relatively quiet since the debate fallout, scolded Pelosi on his Truth Social platform as a "cognitive mess" after her remarks.

He also called Clooney a "fake movie actor" and said he "should get out of politics and go back to television."

Fellow NATO leaders appeared to rally round Biden as he greeted them on arrival.

French President Emmanuel Macron, himself under pressure after calling an inconclusive snap election, gave the older man a hug and a firm handshake on the podium.

Biden, who gave a forceful speech pledging new air defenses for Ukraine as the summit opened on Tuesday, got through his opening remarks with only a couple of verbal stumbles.

But his every move from now until November will now be watched for evidence of age-related frailty or ill health.

Republicans also turned the screw with the House Oversight Committee, which the party controls, issuing subpoenas for three top White House aides to testify about Biden's health.