Could US President Biden quit? It's happened before

Analysis: Could US President Joe Biden refuse to run for another term?

It's the question few people were asking at the start of the week, but after a widely panned debate performance on Friday, it's become a hot topic of conversation.

American politics are so deeply polarised it's hard to find consensus on anything, but it seems there is almost universal agreement that Biden, 81, failed to perform and severely ramped up concerns about his age.

The pundits were scathing, and not just in conservative circles - The New York Times called for Biden to step aside in a staff editorial, writing "the greatest public service Mr Biden can now perform is to announce that he will not continue to run for re-election". The Atlantic blared in a headline, "Time To Go, Joe." Influential columnist Thomas Friedman began his column by saying, "I watched the Biden-Trump debate alone in a Lisbon hotel room, and it made me weep."

People act as if changing horses this close to Election Day could never happen. But it's happened before in American politics, although not recently, and never quite so close to an election.

There's even a little precedent in New Zealand - remember that Jacinda Ardern became the Labour Party leader less than two months before the 2017 election.

The complicated rules of US politics mean that at this point, Biden will have to actually step aside in order to release his pledged delegates before the late August nominating convention.

The last US president eligible to run again, but who chose not to, was Lyndon B. Johnson in 1968, who, facing health woes and rising opposition to the Vietnam war, stunned America with his announcement in March 1968.

A chaotic Democratic race and famously violent Chicago convention ended with Vice President Hubert Humphrey being picked, but losing to Republican Richard Nixon in November.

But the American presidency is a powerful drug, no matter what the party - every single president has had to have a powerful ego and only a few have ever refused to run for a second term when they were eligible.

President Calvin Coolidge, a man of few words, famously signed off with a one-sentence typewritten statement handed to reporters: "I do not choose to run for president in 1928."

Biden would do well to consider two unfortunate historic comparisons - Franklin D. Roosevelt, who won a record four presidential elections, and died at just 63 in 1945 only a few months after winning that fourth term.

And infamously, President Woodrow Wilson had a massive stroke during his second term in 1919, and historians now generally recognise that he was dangerously incapacitated and unable to fulfill the duties of his office afterwards.

The 25th Amendment to the US Constitution, finally passed in 1967, aims to prevent future uncertainties if a president should become incapable.

The days when conventions were suspenseful

Before the tightly choreographed modern media spectacle of televised American political conventions really took off in the 1950s, nominees often would not be certain until the convention itself.

Since the current primary system - where each state votes on possible nominees - was bedded in during the 1970s, there has been very little last-minute drama on who the candidates would be. Occasionally a 'dark horse' like Jimmy Carter or Barack Obama rises up during the primary process, but conventions have largely been unsurprising for years.

It's now been generations since many Americans saw a contested convention.

Once upon a time American politics had the stereotype of the smoke-filled room where party bosses - all white, all male, of course - would coronate a nominee, instead of letting the public be part of the process.

If Biden quits and the process is open to potential nominees like Vice President Kamala Harris, California Governor Gavin Newsom and Michigan Governor Gretchen Whitmer, you could have long, drawn-out ballots as the convention delegates vote over and over to achieve a majority.

One could argue this could give some much-needed excitement to the moribund US political process, but it could also end in nasty gridlock.

For instance, in 1924, Congressman John W. Davis took 103 ballots and 17 days to win the Democratic party's nomination. Spoiler alert - he never became President Davis, either.

Long ballots and convention battles also resulted in some of America's least memorable presidents - names like Warren Harding, Franklin Pierce or William Howard Taft.

It's a fool's game trying to predict what might happen in American politics these days. But it will be very hard for Biden to erase the stain of a dismal debate performance, and time is running out before August's nominating convention in Chicago.

While the headlines are calling for Biden's gracious exit, it's entirely possible that a whole new kind of chaos could erupt if the doors are thrown wide open. And at the moment, the choice over what happens next is in Biden's hands.