It’s been a sobering two weeks for fans of America’s septuagenarian president. Even before he took office, Joe Biden was telling the world ‘America is back’ — a refrain he repeatedly returned to both in official speeches and on his personal Twitter account. But as the scenes of Afghanistan’s rapid collapse have appeared on timelines and televisions across the West, such confident assertions have curiously disappeared from the rhetoric of the supposed ‘leader of the free world.