Nancy Pelosi, Hakeem Jeffries, Chuck Schumer and Adam Schiff are about as influential as you can get within the Democratic party.

Whilst not all of them have publicly called for Mr Biden to step down, the fact theyre not denying reports of private conversations is notable.

Ms Pelosi in particular is a battle-scarred politician who plays a good game of 3D chess.

She doesnt want to be accused of disloyalty to the president she admires but equally doesnt want to be seen as complicit if Democrats suffer huge losses under Mr Biden in Novembers election.

The New York Times reported that Mr Schumer was shown data from a top Democratic fundraising committee that alarmed him “ the president is trailing behind in the must-win states of Pennsylvania, Michigan and Wisconsin.

Many analysts believe Mr Bidens path to victory lies through this area of the country. Theres also some evidence that Nevada, Georgia and Arizona could be slipping away.

President Biden himself has revised his view on what it would take for him to bow to the growing pressure.

He has gone from stating only the Lord Almighty could make him stand down, to telling BET (Black Entertainment Television) that he would re-evaluate his campaign if his doctor diagnosed him with a medical condition.

Then he announced he had Covid.

While hes had the illness before, the latest infection has exacerbated the ongoing concerns about his age, health and fragility.

To now get general malaise, as the doctors put it, is not a great look for a leader many Americans already worry is past it.

The attempted assassination of Donald Trump appeared to have quelled the Democratic rebellion a week ago, but perhaps the reality is its compounded it.

Politics isnt just about the strength of policies. Its about projecting physical strength as a leader.

Many Republicans here at the RNC said to me they are happy for Mr Biden to stay in the race because they believe he is no competition for Trump. And polls aside, their confidence is not unfounded.

Contrast yesterdays video of a fragile President Biden walking slowly down Air Force One with images of a death-defying Trump pumping his fist shouting Fight! Fight! Fight!.

Ultimately, the decision to stand down has to come from Mr Bide. He is dismissive of polls, pointing to Trumps election 2016 victory, his own in 2020 and most recent midterm elections that were supposed to be a disaster for his party.

There are also Democrats who are still fully behind the president and consider him to still be sharp.

But with the Democratic National Convention a month away when the nomination is sealed, it feels as if the clock has again reset and is ticking. (BBC)