Former president Donald Trump believed in a conspiracy theory so ardently it may have cost him the election, a new book has claimed.
Wall Street Journal reporter Michael Bender wrote in his forthcoming book 'Frankly, We Did Win This Election': The Inside Story of How Trump Lost, the former president believed Joe Biden would secretly drop out of the race.
According to the book, Trump told his advisers he believed the current president would be replaced so held off early attacks on him.
The book claimed Trump said the Democrats would "realise [Biden is] old, and they're going to give it to somebody else. They're going to give it to Hillary [Clinton], or they're going to give it to Michelle Obama".
Bender wrote Trump held on to the theory despite a person in his circle trying to douse the belief.
The journalist claimed it was part of the reason Trump "held off on heavy spending against Biden".
The book claims the theory emerged from former Clinton White House adviser Dick Morris, who reportedly told Trump Biden was "too old and too prone to gaffes to be the nominee".
Trump was worried focusing firepower on Biden would be wasted effort, with an early attack on candidate Elizabeth Warren backfiring.
"The president, meanwhile, had often complained that his early attack on Warren had damaged her presidential bid, which he regretted because he viewed her as an easier opponent than Biden," Bender wrote.
"Now he worried that a heavy blitz of attack ads would hasten the secret plot being hatched by Democrats, and his mind raced with who they might select in Biden's place."
Campaign pollster had tried to debunk wild theory
An excerpt from the book, obtained by Vanity Fair, said Trump campaign pollster Tony Fabrizio tried to debunk the theory in a campaign memo.
"I know there is some concern (which I strenuously disagree with) that if we go after Biden too soon, we can collapse him, and the Dems will replace him at their convention. I know POTUS tends to share this opinion," the memo said, according to Bender.
The journalist said Fabrizio outlined Biden however, had the delegate math as a result of the Democratic Primaries and no significant challenger.
"Biden would have enough delegates to secure the nomination in just three weeks, Fabrizio explained, and it would be mathematically impossible to steal it in four weeks," Bender wrote.
Bender's book is due to be released on August 10.
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