Trump bought into conspiracy theory that Democrats would sabotage Biden, replace him with Hillary Clinton or Michelle Obama as presidential nominee, book says

• Trump believed that Biden would be sabotaged and replaced as the 2020 Democratic nominee.
• Trump firmly believed in a conspiracy theory that Hillary Clinton or Michelle Obama would take over.
• The Wall Street Journal's Michael Bender reports on the episode in his upcoming book.
• See more stories on Insider's business page.

Former President Donald Trump believed a conspiracy theory that leaders in the Democratic Party would sabotage now-President Joe Biden at the 2020 convention and replace him with Hillary Clinton or Michelle Obama, according to a forthcoming book by Wall Street Journal reporter Michael Bender.

The latest nugget from the book, titled "Frankly, We Did Win This Election: The Inside Story of How Trump Lost," was published on Monday in Vanity Fair.

As late as April 2020, when all of Biden's rivals had dropped out of the race, Trump bought into the falsehood that Democratic officials would replace Biden, who Trump referred to as "mentally retarded," with Clinton or Obama, Bender wrote.

The idea, he wrote, apparently originated from former Clinton White House advisor Dick Morris who was informally advising Trump at the time.

Trump theorized that Democrats would "realize [Biden is] old, and they're going to give it to somebody else. They're going to give it to Hillary, or they're going to give it to Michelle Obama."

The conspiracy, according to Bender, led Trump to hold back on going after Biden because he was afraid that early and sustained attacks from the Trump camp could weaken Biden so much that Democrats would replace him with another candidate.

Eventually, Trump's former top pollster Tony Fabrizio had to talk the former president down from the idea in a memo spelling out how the mechanics of the nomination process would preclude Biden's last-minute replacement.

"The pollster aimed to debunk the theory by outlining the remaining Democratic primaries, in which Biden had no significant challenger, and the delegate math to secure the nomination," Bender wrote. "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."