The left-wing French Communist Party (PCF) proposed to the French Section of the Workers' International (SFIO, later formed the Socialist Party) to present a candidate with a common programme, but the SFIO refused. The Left was severely divided in this election. The PCF candidate was Jacques Duclos, one of the historical leaders of the party. The mayor of Marseille, Gaston Defferre, was the SFIO candidate and campaigned with Pierre Mendès France, who would have become Prime Minister had Defferre been elected to the Presidency. This candidacy was the first – and so far, only – dual "ticket" in a French presidential election. But Defferre's campaign was weakened by the decision of centrist interim President Alain Poher to run. As Chairman of the Senate, Poher had led the "no" campaign in the referendum. The success of the "no" campaign gave him the legitimacy to run for the Presidency and he rallied a large swathe of centre-right and centre-left voters.