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, revealed in her book about her three-month campaign that she did not discuss with President Biden her concerns over his ability. Nor did the then 81-year-old raise the issue with her.

In her 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 wrote 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 a conversation with him, urging him not to run. She questioned whether it was grace or recklessness that stopped her from speaking up.

Her worry, she added, was not Biden's capacity to do the job of commander in chief but about whether he would meet the demands of a gruelling election campaign to stay in the White House.

When pressed on why there is a distinction, she said there was a serious difference between running for the office and conducting the duties of being president. She expressed particular concern about Biden's stamina in running against Trump.

Harris acknowledged the difficulty in voicing her concerns, fearing accusations of promoting her own political interests.

The topic of who in Biden's inner circle could have challenged his decision to run has gained traction in political discussions, with some experts suggesting there may have been a cover-up regarding his health.

Now, Harris, promoting her new book, hinted it's possible she could run for president again, stating she's not done with public service and ruling out a gubernatorial run in California.