Former President Joe Biden long faced White House concerns about not only his acuity but his longevity, according to a new book.

Aides to Vice President Kamala Harris constructed a “death-pool roster” of judges who could swear her in if he died, Jonathan Allen of NBC News and Amie Parnes of The Hill wrote in “Fight: Inside the Wildest Battle for the White House.”

According to excerpts shared by the Guardian on Thursday, former Harris communications director Jamal Simmons had planned for Biden’s possible demise to the point that the roster of judges was drawn up. In 2023 Democratic National Committee officials had already begun formulating contingencies for a Biden withdrawal from a reelection bid, the book claimed.

Simmons “never told the vice president about the death-pool roster before leaving her camp in January 2023 but he advised colleagues that he should be notified immediately if something happened to Biden, because he had worked out an entire communications strategy,” the authors wrote. “And he left the spreadsheet with another Harris aide.”

HuffPost reached out to Simmons for comment.

The book, due out April 1, also provided details about the aftermath of Biden’s doddering debate against Donald Trump that prompted the incumbent’s withdrawal from the race.

At a reception hosted by New Jersey Gov. Phil Murphy a few days after the debacle, Biden reportedly required florescent tape on the carpet ― “colorful bread crumbs showed the leader of the free world where to walk.”

“He knows to look for that,” one aide said, per the book.