Former CNN editor-at-large Chris Cillizza admitted that there's "ample evidence" of former President Joe Biden's aides covering up his cognitive decline during his administration in an email to FOX News Digital.

"I think there is now ample evidence that there was a cover-up on Joe Biden’s actual physical and mental condition by his aides in the White House. There’s been a ton of reporting on it… too much, I think, to dismiss it," Cillizza wrote.

Cillizza, who now has his own Substack blog, specified that he doesn't believe the press was part of the alleged cover-up.

"Instead, I think the Biden team made it really hard to ask questions about his health — they shamed you, said you didn’t like him, etc.," Cillizza said, claiming that reporters, including himself, "let that be that" and said he doesn't believe President Donald Trump's team would receive the same treatment.

Cillizza claimed that some reporters took the Biden's administration's word as they were more "inclined to believe a Democratic president" or "someone who hadn't said 30,000 false or misleading things while in office."

Biden's team reportedly debated over whether to make him take a cognitive test in February 2024 amid concerns about his mental awareness and age, according to a new book. New York Times reporter Tyler Pager, Wall Street Journal reporter Josh Dawsey and Washington Post reporter Isaac Arnsdoft wrote the book titled 2024: How Trump Retook the White House and the Democrats Lost America, which is set to be released in July and shares details about the 2024 presidential election.

The book reportedly includes Biden's top aides deciding not to have him complete a cognitive test during the final months of his presidency to suppress concerns about his age, despite being confident that he would pass the test.

“At the same time, Mr. Biden’s longtime doctor, Kevin O’Connor, had told aides he would not take the 81-year-old president’s political standing into consideration when treating him,” the New York Times reported, citing the upcoming book.

The debate over the cognitive test took place just weeks before former President Biden's physical exam and several months before his disastrous performance against Trump in the first presidential debate. Special Council Robert Hur's report about Biden's mishandling of classified documents, which described the then-president as “a sympathetic, well-meaning, elderly man with a poor memory," was released during the same month that the aides debated having him undergo a cognitive test.

The book also reportedly included a heated phone conversation between former Biden chief of staff Ron Klain and David Axelrod, who previously served as an aide to former President Barack Obama and frequently appears on CNN. Axelrod was quoted as saying, “The stark reality is the president would be closer to 90 than 80 at the end of a second term, and that would be a major issue," during a June 2022 New York Times report, which "prompted an angry call to Mr. Axelrod from Ron Klain, then Mr. Biden’s chief of staff," according to the upcoming book.

“There’s no Obama out there, Axe,” Klain said during the call, according to the New York Times. “Who’s going to do it if he doesn’t do it?”

Biden announced his decision to end his re-election campaign in July 2024, eventually being replaced by then-Vice President Kamala Harris, who was defeated by Trump in the November election.

The Herd with Colin Cowherd