Exclusive: Read the private email Obama sent his former doc after he questioned Biden's cognitive health

Former President Barack Obama reprimanded his own former White House physician for criticizing Joe Biden's cognitive health on the 2020 presidential campaign trail, according to a forthcoming book.

In his memoir "Holding the Line: A Lifetime of Defending Democracy and American Values," Rep. Ronny Jackson, R-Texas, writes about a stern email from Obama for then-presidential candidate Biden’s "crazy statements and concerning mental gaffes" — a criticism he was uniquely qualified to make having served as the White House physician to Presidents George W. Bush, Obama and Donald Trump.

"Biden was on TV again, making crazy statements and concerning mental gaffes; he didn’t know what state he was in or what office he was campaigning for," Jackson recalls of the 2020 campaign season. "He apparently thought at one point that he was running for the Senate and later couldn’t remember what state he was campaigning in. This had been going on for months and was getting worse."

For years, the media had accused Trump of being mentally unwell, and in 2018 many commentators mocked Jackson for saying that a cognitive evaluation Trump had taken showed he was in "excellent" mental shape and "had absolutely no cognitive or mental issues whatsoever."