The history of the left is littered with so-called ‘socialist’ leaders who have disappointed and betrayed their supporters. From Kier Hardie and Ken Livingstone through to Robert Mugabe and Joseph Stalin, the left constantly has to grapple with explaining the errors, compromises and sell-outs of left politicians. So how do we explain their transformations from sometimes inspiring left leaders to wayward and authoritarian rulers? Unfortunately, the answer will not be found in Robert Guédiguian’s new docu-drama, The last Mitterrand, which deals with that peculiarly French reformist figure François Mitterrand, who became the Fifth Republic’s first Socialist Party prime minister and dashed the hopes of millions of leftists by effectively joining rather than challenging the establishment.