USSC Non-Resident Fellow Lester Munson talks to ABC Darwin about what it would take for President Joe Biden to step down and who could persuade him to do so.

"Right now it looks like the first lady (Dr Jill Biden) is kind of guarding the palace as it were and controlling who gets access and who is talking to the president," said Munson.

"And she appears, at least from the outside, to be very interested in him continuing to be a candidate. So this is a real parlour game here in Washington right now, who talks to the president, how do they do it, can they persuade him, because that's what has to happen for him to be swapped out as the Democrats' nominee."