In a sense, Democrats ought to be relieved. After his calamitous presidential debate, Joe Biden delivered one of his most embarrassing gaffes on Thursday, when he introduced Volodymyr Zelensky as ‘President Putin’, and called Kamala Harris ‘Vice President Trump’.

These howlers – which could have been mistaken for hard-right disinformation – are incontrovertible evidence the Democrats need to remove Biden from the ticket.