Jill Biden has insisted her husband’s lacklustre debate performance against Donald Trump should not “define the four years he’s been president”, in a cover interview with American Vogue.

The first lady spoke to the magazine from the secluded presidential retreat of Camp David on Sunday – where her family had gathered following Thursday’s disastrous debate, in which her husband repeatedly froze and stumbled over his answers which were at times incomprehensible.

“We will not let those 90 minutes define the four years he’s been president. We will continue to fight”, Mrs Biden said.

‌Democrat donors have turned on the first lady over her failure to advise her husband to pull out of the 2024 presidential race.

“Lots of people are blaming his wife…for not telling him [to step aside],” one told the New York Post.

The Vogue interview was conducted ahead of the CNN debate but the publication followed up with Mrs Biden via phone on Sunday.

Hunter Biden is also said to be one of the strongest voices urging his father to resist the mounting pressure to stand aside.

The New York Times reported that Hunter, 54, is desperate for his father’s awkward display in front of 50 million American viewers on Thursday not to become his legacy, according to a source informed by the ongoing family discussions.

The ageing president’s oldest child is currently facing his own battles, following his federal gun conviction earlier this month and a trial set for September over tax evasion charges.

Mr Biden’s close relatives are said to be accepting of how poorly he performed against former president Donald Trump – but have expressed frustration with the aides that prepared him for the event.

Another person privy to the discussions told The New York Times “the entire family is united”, adding that there was no talk of Mr Biden backing out.

The 81-year-old president has previously said he would never run a political campaign without the backing of his family.

Further sources said Mr Biden was upset by the criticism but was completely committed to staying in the race. In private conversations, he has reportedly asked his aides and allies about what they are hearing amongst the Democrat camp.