For all the widespread fear of a second Donald Trump presidency, the Biden White House could be forgiven for being more preoccupied by the spectre of Jimmy Carter and the baleful images of his last year in office.
Carter was the last Democratic president to serve only a first term, brought low by the searing drama of the Tehran embassy siege, when Iranian revolutionaries had overrun the US diplomatic compound and held 52 American personnel captive for more than a year, heaping international humiliation on a military superpower when the cold war was still at its height.
