Rome, April 18 - A leading Democratic Party (PD) MP called Thursday for a new presidential candidate who can unify the party membership. Simona Bonafe said leader Pier Luigi Bersani must quickly find a candidate that - unlike his previous choice, who failed Thursday amid controversy - can muster support from all the centre-left party's squabbling factions. "I hope he finds a figure that will bring together the Democratic Party," said Bonafe, a supporter of Bersani's increasingly vocal critic Matteo Renzi, the mayor of Florence who consistently polls higher than Bersani both as a possible PD leader and a potential premier. He spoke after Bersani's candidate for president, Franco Marini, failed to win the two-thirds majority needed in the first round of voting earlier in the day. Marini failed even though he had the support of ex-premier Silvio Berlusconi's centre-right People of Freedom (PdL) party as well as some PD members. However, many others in the centre-left PD were alienated by Bersani's choice, made in cooperation with Berlusconi, and instead have gravitated towards constitutional lawyer Stefano Rodota', an ex-Communist Constitutional lawyer. In the meantime, the PD told its parliamentarians and representatives from Italy's regional governments to cast a blank ballot in the second round of voting Thursday evening. At the same time Renzi - a rising star in the party - was set to meet Bersani and other PD leaders to discuss the party's next candidate.