Karine Jean-Pierre leaves Democratic Party, details Biden’s exit in new book

WATCH: Biden answers question about mental decline

Former President Joe Biden spoke at a Memorial Day service in Delaware, marking his first public remarks since announcing he was diagnosed with prostate cancer. After the event, Biden answered questions from reporters - including a question on his mental decline.

NEW YORK - Former White House press secretary Karine Jean-Pierre is out with a new book, set to be released this fall.

She promises a close look at President Biden's decision not to run for reelection and calls for thinking beyond the two-party system.

RELATED: Joe Biden diagnosed with 'aggressive form' of prostate cancer

But one of the book's biggest revelations ahead of its release is that Jean-Pierre herself has switched her affiliation to independent after working in two Democratic administrations, according to Legacy Lit, a Hachette Book Group imprint that will publish "Independent: A Look Inside a Broken White House, Outside the Party Lines" on Oct. 21.

What they're saying:

"Until January 20, I was responsible for speaking on behalf of the President of the United States," Jean-Pierre, the first Black woman and openly gay person to hold the position of White House press secretary, said in a statement released Wednesday.

Former White House press secretary Karine Jean-Pierre speaking during a news conference in the Brady Press Briefing Room at the White House on January 13, 2025, in Washington, DC. (Photo by Andrew Harnik/Getty Images)

"At noon on that day, I became a private citizen who, like all Americans and many of our allies around the world, had to contend with what was to come next for our country. I determined that the danger we face as a country requires freeing ourselves of boxes. We need to be willing to exercise the ability to think creatively and plan strategically."

Who is Karine Jean-Pierre?

The backstory:

Jean-Pierre, 50, succeeded Jen Psaki as press secretary in 2022 after previously serving as deputy press secretary and also working as a senior adviser during Biden's victorious 2020 campaign. During President Barack Obama's first term, she was a regional political director.

RELATED: Biden's team considered wheelchair amid health concerns: New book

Jean-Pierre was criticized at times for being evasive about Biden's physical condition. Wednesday's announcement from Legacy Lit says that she will take readers "through the three weeks that led to Biden’s abandoning his bid for a second term and the betrayal by the Democratic Party that led to his decision."

New book alleges Biden aides covered up mental decline

A new book by CNN's Jake Tapper and Axios reporter Alex Thompson alleges aides to former President Joe Biden covered up his mental decline towards the end of his term.

"She presents clear arguments and provocative evidence as an insider about the importance of dismantling the torrent of disinformation and misinformation that has been rampant in recent elections and provides passionate insight for moving forward," the announcement said.

Big picture view:

Jean-Pierre's book could be one of the few by former White House press secretaries to make news. Scott McLellan, President George W. Bush's press secretary from 2003-2006, made headlines when he criticized Bush and other administration officials in the 2008 bestseller "What Happened."

Questions surround Biden's health

Dig deeper:

Concerns about former President Biden’s mental sharpness had been growing among conservatives even before the 2020 election. 

RELATED: Ex-Biden aide says former president was 'fatigued, befuddled, and disengaged' prior to June debate

These worries heightened in February 2024 when special counsel Robert Hur, investigating Biden’s handling of classified documents from his time as vice president, declined to recommend charges. In his report, Hur described Biden as "a sympathetic, well-meaning, elderly man with a poor memory."

Recordings show President Biden's memory lapses

In newly released audio from former President Joe Biden's interview with Special Counsel Robert Hur, the president appeared to have difficulty recalling significant events. These included the date of his son Beau's death and when he concluded his vice presidency.

Public anxiety over Biden’s mental fitness peaked in June 2024 during his debate with Republican presidential candidate Donald Trump. His lackluster performance alarmed not only critics but also longtime allies, many of whom began urging him to step aside for a younger Democratic leader.

Biden withdrew from the race at the end of July 2024, handing the nomination to former Vice President Kamala Harris, who had just over 100 days to mount a campaign. Ultimately, Trump and his running mate, JD Vance, won the election after securing key battleground states.

According to an upcoming book, Biden’s aides privately discussed the possibility of using a wheelchair for the president if he had been re-elected, due to his worsening physical condition in 2023 and 2024. The book, "Original Sin: President Biden’s Decline, Its Cover-Up, and His Disastrous Choice to Run Again," claims Biden’s unsteady gait had grown so concerning that internal conversations about a wheelchair took place—but officials delayed any such move until after the election.