US President Joe Biden announced on Sunday that he is withdrawing from the race to be president for a second term. The announcement on his personal X account came after massive pressure from within his own Democratic Party not to put himself forward as the party’s official nominee. A television debate performance against his rival Donald Trump at the end of June, during which 81-year-old Biden struggled several times to give coherent answers or challenge falsehoods uttered by Trump, prompted nationwide concern about whether he was still mentally fit for office. The issue of Biden’s age has sin…