When does the promotional tour for a book turn into a potential public-relations headache? That's the question raised by the blowback to "Original Sin," the behind-the-scenes look at Joe Biden's age-related infirmities,

Jake Tapper and Alex Thompson's book has already generated a national debate about whether the White House deceived the public about the president's cognitive state and how Biden's late exit from the race undermined the Democratic Party's chances of stopping Trump.