Former US Vice-President Kamala Harris has expressed concern that she did not ask Joe Biden to pull out of the race for the White House.

In an interview with the BBC for Sunday with Laura Kuenssberg, she said: I do reflect on whether I should have had a conversation with him, urging him not to run for re-election.

After months of speculation about his health and mental acuity, President Biden ended his re-election bid in July 2024 after a disastrous performance in a debate against Donald Trump a few weeks earlier.

Harris, who stepped in as the Democratic nominee but lost to Trump, has revealed in her book about her three-month campaign that she did not discuss her concerns over Biden's ability with him, nor did the then 81-year-old raise the issue with her.

In the book, 107 Days, the former vice-president wrote that Biden's decision to run again was a choice that shouldn't have been left to an individual's ego, an individual's ambition. She mentioned that perhaps she should have raised it with him.

In this interview she told the BBC that she still ponders whether she should have acted differently and talked to him about it. I do reflect on whether I should have had a conversation with him, urging him not to run, she said, questioning whether it was grace or recklessness that stopped her from speaking up.

Her worry, she added, was not Biden's capacity to be commander-in-chief but about whether he would endure the demands of a challenging campaign to stay in the White House.

When pressed on why there is a distinction, she explained that there is a significant difference between running for the office and conducting the duties of being president. Running against Trump posed even more demands, she said.

Harris raised concerns about Biden's energy and endurance necessary for the campaign, stating, especially running against the now current president.

She found it difficult to voice her concerns, fearing that she would be seen as promoting her political ambitions by confronting Biden about his health.

Discussions on whether more people around Biden should have questioned his decision to run again have become a significant topic of conversation.

Additionally, allegations arose in Original Sin by Jake Tapper and Alex Thompson, claiming that Biden's close associates concealed his physical deterioration. However, Biden's aides have dismissed these claims, asserting that while visible changes occurred with age, they found no evidence indicating mental incapacity affecting his job performance.

In a recent interview shortly after leaving the White House, Biden mentioned that it would not have made a difference even had he left the race earlier.

As she promotes her book, Harris also indicated that it is possible for her to run for the White House again, asserting that she is not finished with public service.