Why can't Trump accept his defeat?

With his defeat in the US presidential election, Donald Trump finds himself fighting against being tagged with a label he frequently applies to rivals but which runs completely counter to his own brand: "loser."

The Republican is pursuing legal action in several battleground states, though his lawyers have so far failed to substantiate claims of fraud and observers see the possibility of the courts overturning the result of the vote as vanishingly small.

Yet according to scholars and mental health professionals, the same authoritarian qualities that defined Trump's rise to power and his presidency make it almost impossible for him to digest a graceful concession to Democratic President-elect Joe Biden.

This, they warn, could make the post-election, pre-inauguration period a particularly unstable time for the country.

Ruth Ben-Ghiat, a professor of history at New York University, told AFP that Trump had tried to establish an "authoritarian model of the presidency" based on "arrogance, brutality, and the idea that he must be defended from his enemies."

"It's easier to claim the whole election was a fraud than admit that his policies turned his people against him in numbers sufficient to ensure his defeat" added the author of the forthcoming book: "Strongmen: Mussolini to the Present."

Having claimed victimhood at the hands of ignoble forces that coalesced against him, "we can expect him to continue in this vein and delay the public humiliation of a concession speech," she said.

"We should be watchful of what he might do over the next months in a vindictive spirit," she argued.

That conclusion was shared by John Gartner, a Baltimore-based psychologist who is among a growing number of mental health professionals who have publicly warned that Trump is a "malignant narcissist."

People who have this personality type -- first coined by famed psychoanalyst Erich Fromm to explain "the quintessence of evil" -- exhibit narcissism, antisocial personality disorder, paranoia, and sadism.

Gartner said he was worried that Trump may attempt to pursue a "Nero decree" or "scorched Earth" strategy as a means to deal with his loss.

But he added he was hopeful that given the stinging loss, the president would start to lose his grip on some of his followers.

'Nobody to bail him out' -

For Mary Trump, the president's niece and one of his most strident critics, her uncle's decision to declare himself the winner of the election and accuse his rival of cheating spoke of his desperation at circumstances he wasn't accustomed to.

"Donald has never been in this place before where there's nobody to bail him out, there's nobody to buy him out," the clinical psychologist, who wrote a memoir on her uncle over the summer, told MSNBC.

In her book, she argued that the president is a product of his "sociopath" father Fred Trump, who created an abusive and traumatic home life.

Trump has built his public persona on the idea of being a winner -- first in the rough-and-tumble world of New York real estate, and later on the show "The Apprentice," where he pitched the mythology of his business acumen, despite his numerous corporate bankruptcies.

He's also sought to contrast his record as a big business boss with the life-choices of his rivals. In 2015, he famously dubbed the late senator John McCain a "loser" and said of the Vietnam veteran and prisoner-of-war, "I like people who weren't captured."

Just weeks before the election, meanwhile, Trump told supporters in Georgia that Biden was the "worst candidate in the history of presidential politics."

"Could you imagine if I lose?" he mused, before adding: "Maybe I'll have to leave the country?"

Lawrence Douglas, author of "Will He Go? Trump and the Looming Election Meltdown in 2020," argued there are prudential reasons why remaining in high office is beneficial.

In addition to being hundreds of millions of dollars in debt, he is facing defamation cases by women who have accused him of sexual misconduct and even potential criminal charges stemming from his business practices -- with his immunity ending when he is no longer president.

But beyond that, Trump's refusal to concede helps keep his connection alive with his base, said Douglas. "In defeat, his brand will remain irresistible to his supporters."