Biden shores up support but doubts remain among some Democrats

President Joe Biden won much-needed support from senior Democrats and gave a confident NATO summit speech Tuesday, but doubts over his age and fitness continued to dog his reelection bid.

The top Democrat in the House of Representatives, Hakeem Jeffries, held meetings with members about whether to ditch Biden as their 2024 candidate following his disastrous debate performance against Donald Trump.

Biden meanwhile tried to prove he still has what it takes on the world stage, addressing NATO leaders in Washington, DC for the alliance's 75th anniversary in a closely-watched speech.

Reading from a teleprompter, Biden spoke forcefully about the "moment in history", making almost none of the verbal stumbles that made the June 27 debate so painful for his supporters to watch.

After days in which his fate hung in the balance, Biden has looked to move on and the party meetings on Tuesday were a pivotal moment.

An initial meeting with lawmakers who fear their seats could be at risk in November was "intense," one member told US media, with another saying the mood was "pretty much unanimous" that Biden should step down.

But in the party's full caucus meeting later Tuesday there were signs that Biden has firmed up support, with several lawmakers walking past rows of reporters and declaring their allegiance to the president.

Jerry Nadler, the ranking Democrat on the House Judiciary Committee, backed Biden despite having reportedly said at the weekend that he should step aside.

"He said he's going to remain in, he's our candidate, and we're all going to support him -- hopefully we're all going to support him," Nadler told reporters.

Even though the endorsements weren't all enthusiastic, there appeared to be grudging acceptance that Biden is not going anywhere, at least for now.

The White House has tried to insist through a series of increasingly heated press briefings that the matter is settled and the party is united.

"We do want to turn the page," Biden's spokeswoman Karine Jean-Pierre said Tuesday. "We want to get to the other side of this."

- 'Step down' -

Most top Democrats -- such as Senate Majority Leader Chuck Schumer, who reiterated Tuesday that "I'm with Joe" -- have rallied behind Biden, even as the party remains divided over a dismal debate performance watched by some 51 million Americans.

Stubborn resistance remained Tuesday, with New Jersey congresswoman Mikie Sherrill becoming the seventh Democratic lawmaker to openly call on Biden to not seek reelection.

Republicans in Congress have largely stood back and enjoyed the Democratic implosion, although Trump pulled no punches as he brought up the crisis at his first rally in 11 days at his Doral golf resort in Miami.

"They want Crooked Joe out of the race. It's a shame the way they're treating him. But don't feel sorry for him. He's a very bad guy," Trump told supporters as he embarked on 75 minutes of invective mainly targeting his election rival.

Concerns about Biden's health have upended the party less than four months before the vote.

Biden stepped up his fightback this week, saying he would stay in the race and daring Democratic critics to challenge him at the party convention in August.

The oldest-ever US president has dismissed his debate performance, in which he stumbled over words and stood with mouth agape, as a "bad night" caused by a cold and jetlag from arduous foreign travel.

Biden's personal doctor said Monday the president was seen by a specialist in Parkinson's disease purely as part of normal neurological examinations during his annual medical.

Biden's attempted relaunch has however failed to convince The New York Times.

In a scathing editorial, it said Democrats "need to tell him that he is embarrassing himself and endangering his legacy."