Biden aide hits back at book alleging cover-up of his 'deterioration'1 day ago Share Save Brandon Drenon BBC News, Washington DC Share SaveGetty ImagesJoe Biden's aides have hit back at a new book that accuses a White House inner circle of covering up the former US president's "physical deterioration" during his ill-fated re-election campaign. A spokesperson for Biden, 82, said "evidence of aging is not evidence of mental incapacity" and maintained the Democrat had been "a very effective president". The book, by CNN's Jake Tapper and Alex Thompson of Axios, is due to be released on 20 May. Biden abruptly ended his re-election campaign last July shortly after his disastrous debate performance against Donald Trump, a Republican. Not long after the incident, Clooney wrote an opinion piece in the New York Times calling on Biden to quit the race.