Now a week out from the United States general election and with many indicators pointing to a Biden victory, the question has come into sharper focus.

Its answer would shed light on the future of vice-presidential candidate Kamala Harris and just how big a role she would play in a Biden administration.

Mr Biden has not revealed what he would do in 2024, but he has said he views himself as a “transitional candidate” and his campaign as a “bridge” to a new generation of Democratic leaders.

Politically, it would put him at a disadvantage in Washington if he signalled he was only planning on being around for one term, rendering him a “lame duck” president.

But four years is a long time in politics, and by 2024, Mr Biden will be 82.

If he wins next week, he will already be the oldest president in US history at 78 years of age.

Would Joe Biden run again?
The US 60 Minutes program ran interviews with the presidential and vice-presidential candidates this week and Mr Biden was asked about his age and the role of his VP candidate.

“Why do you think Senator Harris would be ready to step in and become commander-in-chief were something to happen to you?” interviewer Norah O’Donnell asked.

“Number one, her values. Number two, she’s smart as a devil. Number three, she has a backbone like a ramrod. Number four, she is really principled,” Mr Biden responded.

He then praised Senator Harris’s experience as attorney-general of California, signalling the role prepared her to run the White House if she had to.

“She has had significant experience in the largest state in the union, running the justice department that is only second in size to the United States Justice Department,” Mr Biden said.

“Obviously, you know, I hope that never becomes a question.”

Betsy Fischer Martin, executive director of the Women in Politics Institute at American University, said there were “too many variables” to know who might run in 2024.

“But there’s no doubt that this process of picking a vice-president was significant, especially when you’re an older nominee,” she said.

“He really wanted to have someone in that position that he felt would be ready to govern at any point.”

Democratic future ‘is not an older white male’

Should the Biden-Harris ticket win next week, Senator Harris would become the first female vice-president. And in doing so, she would put women within one move of the Oval Office for the first time.

She would also become the highest office holder of any black woman in American history.

Professor Martin said Senator Harris’s selection as the VP candidate was “the anointing of the future of the party”.

“If they win next week … she would most definitely be the figurehead of the future of the party and the future election, whether that’s in 2024, or 2028,” Professor Martin said.

“The future of the party is not an older white male. The future of the party is female, is diverse, is all of the things that stands for.”

Political commentator and Democratic strategist Patti Solis Doyle told a panel Senator Harris had to “demonstrate that she could be president of the United States” during last month’s vice-presidential debate.

“And boy did she do that in my opinion. There were just no questions whatsoever,” she said.

How do Biden and Harris compare politically?

While Senator Harris’s election to the office of the vice-president would be a huge win for the representation of women and people of colour, in some corners of the Democratic Party she may not be seen as progressive enough.

She is less conservative than Mr Biden, running to the left of him in the primaries, but she may face challenges to her nomination if she is handed the mantle in 2024.

GovTrack ranks her as the most liberal senator, but her record as a criminal prosecutor may not sit well with all Democrats.

According to Professor Martin, Senator Harris is very much considered a moderate.

In terms of what kind of VP she would be, in her 60 Minutes interview, Senator Harris said she had signed up to “Joe’s plan”.

“I would not have joined the ticket if I didn’t support what Joe was proposing,” she said.

“What I will do, and what Joe wants me to do — this was part of our deal — I will always share with him my lived experience as it related to every issue that we confront and I promised Joe that I will give him that perspective and always be honest with him,” she said.

“It is the perspective of a woman who grew up as a black child in America, who was also a prosecutor, who also has a mother who arrived here at the age of 19 from India.”

Ms Solis Doyle, who worked on the Obama-Biden campaign in 2012, said Senator Harris would be “in the room”.

“I fully expect Kamala Harris to be a partner because that’s what I know Joe Biden is looking for in a vice-president, having done the job for eight years,” she said on the Brunswick Group panel.

“Someone that he could govern with, someone who can be … the last person in the room and give him the soundest advice.”

What a one-term pledge could mean for Democrats

David Smith from the United States Studies Centre said just how progressive the agenda of a Biden administration turned out to be would come into play if Senator Harris was to run in 2024.

“It would certainly cause quite a bit of chaos within the Democratic Party because Kamala wouldn’t get the nomination automatically by any means,” he said.

In that situation, an incumbent vice-president would have to fight to win the Democratic Party’s nomination for the presidency.

“There would be a competitive primary and she would be the Biden-backed candidate, but there would certainly be challenges from the left as well — unless Biden’s legislative agenda turns out to be very progressive, and that would allow Harris to run as progressive,” Mr Smith said.

Professor Martin agreed, saying: “If they feel the issues that are important to them haven’t been addressed in any meaningful capacity, then I think you’ll see somebody running from that wing of the party.”

In an interview last week, Vermont senator Bernie Sanders was asked if he would mount a challenge to Mr Biden or Senator Harris in 2024, if any administration they formed did not move to the left.

Senator Sanders did not rule it out.

“To answer your question, am I prepared to support primary challenges all across this country to those members of Congress Democrats who are not prepared to move toward a progressive agenda? You’re damn right I am,” he said.

Does all of this get a woman closer to being sworn in on January 20, 2025?
For Senator Harris to become president in 2025, a series of events have to take place.

First and foremost, the Biden-Harris ticket has to win next week.

Then in four years, Mr Biden has to signal he’s moving out of the way and endorse Senator Harris.

Then she would have to survive any challenges from inside her own party to secure the nomination and then defeat Trump’s Republican replacement in the general election in November, 2024.

So, the road is not an easy one and it depends on a lot more than the events of next week.

But that is just one scenario, involving one possible female candidate from one party.

Republicans may well have women as part of their 2024 primary pack too.

Former Republican governor and UN ambassador Nikki Haley sparked speculation she was sizing up a run at the presidency in 2024 at the party’s national convention.

Analysis at the time said Ms Haley’s speech to the party faithful “showcased a more compassionate brand of Republicanism” as she spoke about being elected as Georgia’s “first minority and first female governor”.

“I think there’s no doubt that she is positioning herself and doing all the right things so that if there is a 2024 opportunity, she would be front and centre in that,” Professor Martin said.

And the question has to be asked: does that mean the day with two women candidates at the top of major party tickets could be in sight?

“We could certainly see a situation where we have two women as the nominees,” Professor Martin said.

Opposition to Senator Harris running at the top of the ticket has already begun.

In The Villages, Florida last week, Mr Trump once again had an anti-socialist message, this time linking it to the Democratic VP candidate.

“We’re not supposed to have a socialist — look we’re not going to be a socialist nation. We’re not going to have a socialist president, especially a female socialist president, we’re not going to have it, we’re not going to put up with it,” he said.

He made similar comments at the Republican National Convention.

During the 60 Minutes interview Senator Harris was asked if she would bring socialist policies to a Biden White House.

She laughed at the suggestion.

“I am not going to be confined to Donald Trump’s definition of who I am [or who] anybody else is,” she said.