On Friday, one of those biographers, David Maraniss, weighed in with a tweet: “Willl [sic] say this once only. David Garrow, author of new Obama bio, was vile, undercutting, ignoble competitor unlike any I’ve encountered.” The controversy comes as Obama himself starts to mould his post-presidential career. This week, he unveiled the conceptual design of his presidential library and museum in Chicago and released a video endorsing the centrist Emmanuel Macron in the French election. On Sunday, the 55-year-old will deliver his first major speech since leaving the White House when he receives a John F Kennedy Profile in Courage award in Boston. He has not, as yet, offered direct criticism of his successor, Donald Trump.