Donald Trump has admitted he did not win the 2020 election.

“I didn’t win the election,” he said.

The admission came in a video interview with a panel of historians convened by Julian Zelizer, a Princeton professor and editor of The Presidency of Donald Trump: A First Historical Assessment. The interview was published on Monday by the Atlantic.

Describing his attempts to make South Korea pay more for US military assistance, Trump said Moon Jae-in, the South Korean president, was among the “happiest” world leaders after the 2020 US election put Joe Biden in the White House.

“By not winning the election,” Trump said, “he was the happiest man – I would say, in order, China was – no, Iran was the happiest.

“[Moon] was going to pay $5bn, $5bn a year. But when I didn’t win the election, he had to be the happiest – I would rate, probably, South Korea third- or fourth-happiest.”

Trump also said “the election was rigged and lost”.

Trump’s refusal to accept defeat by Biden provoked attempts to overturn results in key states in court – the vast majority of such cases ending in defeat – and the deadly attack on the US Capitol on 6 January 2021.

Trump was impeached a second time, for inciting an insurrection, and acquitted a second time after enough Senate Republicans stayed loyal.

Trump thus remains free to run for the White House again in 2024, which he has repeatedly hinted he will do.

Writing for the Atlantic, Zelizer said Trump “was the one who had decided to reach out to a group of professional historians so that we produced ‘an accurate book’”.

The former president called the historians assembled by Zelizer “a tremendous group of people, and I think rather than being critical I’d like to have you hear me out, which is what we’re doing now, and I appreciate it”.

Trump, Zelizer wrote, “seemed to want the approval of historians, without any understanding of how historians gather evidence or render judgments”.

Zelizer also pointed out that shortly after the session with the historians, Trump announced he would give no more interviews for books about his time in office.

“It seems to me that meeting with authors of the ridiculous number of books being written about my very successful administration, or me, is a total waste of time,” Trump said in a statement, in July 2021.

“These writers are often bad people who write whatever comes to their mind or fits their agenda. It has nothing to do with facts or reality.”