(see related stories) Rome, April 18 - Silvio Berlusconi's centre-right People of Freedom (PdL) may cast blank papers in Thursday's second vote to elect the new Italian president. The PdL's Lower and Upper House lawmakers and regional representatives were told to back the centre-left Democratic Party's (PD) Franco Marini, the former Senate speaker, in the first ballot. But Marini failed to win the two-thirds majority needed after a rebellion within the PD. Berlusconi and PdL bigwigs are in a meeting to decide on their strategy, after the candidate they viewed as acceptable failed to win support from the party that proposed him. The PdL's ally, the regionalist Northern League, has said it will not take part in the second and third votes after it too backed Marini in the first round. The PD has already told its members to cast blank papers in the second of Thursday's two votes as it pauses for reflection. A two-thirds majority will be needed to elect a new head of state in Thursday's second vote and in an eventual third ballot on Friday. But a simple majority of 504 will suffice if the election goes to a fourth ballot, which would take place later on Friday. Marini obtained 521 votes in the first ballot, while the anti-establishment 5-Star Movement's candidate, former Communist party MP and ex privacy watchdog chief Stefano Rodota', was second with 240.