Former Democratic Party leader Pier Luigi Bersani casts his vote at the Chambers of Deputies in Rome January 30, 2015. Italian lawmakers failed to elect a new president in a first round of voting on Thursday, leaving Prime Minister Matteo Renzi hoping to push through his candidate only in a fourth round when the required threshold of votes is lower. REUTERS/Remo Casilli (ITALY - Tags: POLITICS ELECTIONS)

Former Democratic Party leader Pier Luigi Bersani casts his vote at the Chambers of Deputies in Rome January 29, 2015. The unity of Prime Minister Matteo Renzi's party and the strength of his alliance on reforms with opposition rival Silvio Berlusconi will be tested on Thursday with a parliamentary vote to choose a new president. REUTERS/Alessandro Bianchi (ITALY - Tags: POLITICS ELECTIONS)

Italy's Prime Minister Matteo Renzi (L) embraces former PD (Democratic party) leader Pier Luigi Bersani in the lower house of the parliament during a confidence vote in Rome February 25, 2014. Renzi won his first confidence vote in parliament, pledging to cut labour taxes, free up funds for investment in schools and pass wide institutional reforms to tackle Italy's economic malaise. REUTERS/Giampiero Sposito (ITALY - Tags: POLITICS)

Italy's Prime Minister Matteo Renzi claps as former PD (Democratic party) leader Pier Luigi Bersani enters the lower house of the parliament during a confidence vote in Rome February 25, 2014. Renzi won his first confidence vote in parliament, pledging to cut labour taxes, free up funds for investment in schools and pass wide institutional reforms to tackle Italy's economic malaise. REUTERS/Giampiero Sposito (ITALY - Tags: POLITICS)

Former PD (Democratic party) leader Pier Luigi Bersani (2nd L) is greeted by Italy's Prime Minister Matteo Renzi as he arrives for a confidence vote at the lower house of the parliament in Rome February 25, 2014. Renzi won his first confidence vote in parliament, pledging to cut labour taxes, free up funds for investment in schools and pass wide institutional reforms to tackle Italy's economic malaise. REUTERS/Giampiero Sposito (ITALY - Tags: POLITICS)

Roberta Lombardi (C), member of the 5-Star Movement, talks with upper house president Pietro Grasso (L) and his lower house counterpart Laura Boldrini during the third day of the presidential election in the lower house of the parliament in Rome April 20, 2013. Centre-left leader Pier Luigi Bersani announced his resignation on Friday after party rebels sabotaged two separate candidates he had backed for state president, deepening Italy's political chaos. REUTERS/Alessandro Bianchi ( ITALY - Tags: POLITICS ELECTIONS)

Roberta Lombardi, member of the 5-Star Movement, casts her ballot during the third day of the presidential election in the lower house of the parliament in Rome April 20, 2013. Centre-left leader Pier Luigi Bersani announced his resignation on Friday after party rebels sabotaged two separate candidates he had backed for state president, deepening Italy's political chaos. REUTERS/Alessandro Bianchi ( ITALY - Tags: POLITICS ELECTIONS)

Vito Crimi, head of the 5-Star Movement group at the upper house, gestures during the third day of the presidential election in the lower house of the parliament in Rome April 20, 2013. Centre-left leader Pier Luigi Bersani announced his resignation on Friday after party rebels sabotaged two separate candidates he had backed for state president, deepening Italy's political chaos. REUTERS/Alessandro Bianchi ( ITALY - Tags: POLITICS ELECTIONS)

Italy's Prime Minister Mario Monti (L) stands next to Northern League secretary Roberto Maroni (R) at the upper house during the third day of the presidential election in the lower house of the parliament in Rome April 20, 2013. Centre-left leader Pier Luigi Bersani announced his resignation on Friday after party rebels sabotaged two separate candidates he had backed for state president, deepening Italy's political chaos. REUTERS/Alessandro Bianchi ( ITALY - Tags: POLITICS ELECTIONS)

A digital panel is pictured during the third day of the presidential election in the lower house of the parliament in Rome April 20, 2013. Centre-left leader Pier Luigi Bersani announced his resignation on Friday after party rebels sabotaged two separate candidates he had backed for state president, deepening Italy's political chaos. The panel reads, "Pierluigi Bersani didn't answer" REUTERS/Alessandro Bianchi ( ITALY - Tags: POLITICS ELECTIONS)

A member of the parliament holds his ballot during the third day of the presidential election in the lower house of the parliament in Rome April 20, 2013. Centre-left leader Pier Luigi Bersani announced his resignation on Friday after party rebels sabotaged two separate candidates he had backed for state president, deepening Italy's political chaos. REUTERS/Alessandro Bianchi ( ITALY - Tags: POLITICS ELECTIONS)

Vito Crimi, head of the 5-Star Movement group at the upper house, waves during the third day of the presidential election in the lower house of the parliament in Rome April 20, 2013. Centre-left leader Pier Luigi Bersani announced his resignation on Friday after party rebels sabotaged two separate candidates he had backed for state president, deepening Italy's political chaos. REUTERS/Alessandro Bianchi ( ITALY - Tags: POLITICS ELECTIONS)

An overhead view during the third day of the presidential election in the lower house of the parliament in Rome April 20, 2013. Centre-left leader Pier Luigi Bersani announced his resignation on Friday after party rebels sabotaged two separate candidates he had backed for state president, deepening Italy's political chaos. REUTERS/Alessandro Bianchi ( ITALY - Tags: POLITICS ELECTIONS)

A parliament assistant checks the ballot box during the third day of the presidential election in the lower house of the parliament in Rome April 20, 2013. Centre-left leader Pier Luigi Bersani announced his resignation on Friday after party rebels sabotaged two separate candidates he had backed for state president, deepening Italy's political chaos. REUTERS/Alessandro Bianchi ( ITALY - Tags: POLITICS ELECTIONS)

An overhead view during the third day of the presidential election in the lower house of the parliament in Rome April 20, 2013. Centre-left leader Pier Luigi Bersani announced his resignation on Friday after party rebels sabotaged two separate candidates he had backed for state president, deepening Italy's political chaos. REUTERS/Alessandro Bianchi ( ITALY - Tags: POLITICS ELECTIONS)

Ballot boxes are seen during the third day of the presidential election in the lower house of the parliament in Rome April 20, 2013. Centre-left leader Pier Luigi Bersani announced his resignation on Friday after party rebels sabotaged two separate candidates he had backed for state president, deepening Italy's political chaos. REUTERS/Alessandro Bianchi ( ITALY - Tags: POLITICS ELECTIONS)

Democratic Party (PD) leader Pier Luigi Bersani holds his ballot during the second day for the presidential election in the lower house of the parliament in Rome April 19, 2013. Italy's centre-left backed former Prime Minister Romano Prodi as candidate for president on Friday, setting up a battle with the centre-right alliance of Silvio Berlusconi and increasing the likelihood of a snap election within weeks.The election of the next head of state to succeed President Giorgio Napolitano, whose term ends on May 15, is crucial to ending a two-month stalemate since a parliamentary poll in February which left no party able to form a government. REUTERS/Max Rossi (ITALY - Tags: POLITICS ELECTIONS)

A parliamentary checks the online vote count during the presidential elections in the lower house of the parliament in Rome April 18, 2013. Italy's divided parliament begins voting for a new state president on Thursday, with former Senate Speaker Franco Marini the main candidate in a ballot that will severely strain the unity of the centre-left alliance led by Pier Luigi Bersani. The vote for a successor to President Giorgio Napolitano, whose term ends on May 15, will be a crucial step towards resolving the stalemate since the inconclusive election in February left no party with enough support to form a government. REUTERS/Tony Gentile (ITALY - Tags: POLITICS ELECTIONS)

A ballot box is opened for votes to be counted during the presidential election in the lower house of the parliament in Rome April 18, 2013. Italy's divided parliament begins voting for a new state president on Thursday, with former Senate Speaker Franco Marini the main candidate in a ballot that will severely strain the unity of the centre-left alliance led by Pier Luigi Bersani. The vote for a successor to President Giorgio Napolitano, whose term ends on May 15, will be a crucial step towards resolving the stalemate since the inconclusive election in February left no party with enough support to form a government. REUTERS/Tony Gentile (ITALY - Tags: POLITICS ELECTIONS)

Lower house President Laura Boldrini (L) reads the ballots during the presidential election in the lower house of the parliament in Rome April 18, 2013. Italy's divided parliament begins voting for a new state president on Thursday, with former Senate Speaker Franco Marini the main candidate in a ballot that will severely strain the unity of the centre-left alliance led by Pier Luigi Bersani. The vote for a successor to President Giorgio Napolitano, whose term ends on May 15, will be a crucial step towards resolving the stalemate since the inconclusive election in February left no party with enough support to form a government. REUTERS/Tony Gentile (ITALY - Tags: POLITICS ELECTIONS)

A parliamentary assistant carries a ballot box at the end of the presidential election in the lower house of the parliament in Rome April 18, 2013. Italy's divided parliament begins voting for a new state president on Thursday, with former Senate Speaker Franco Marini the main candidate in a ballot that will severely strain the unity of the centre-left alliance led by Pier Luigi Bersani. The vote for a successor to President Giorgio Napolitano, whose term ends on May 15, will be a crucial step towards resolving the stalemate since the inconclusive election in February left no party with enough support to form a government. REUTERS/Tony Gentile (ITALY - Tags: POLITICS ELECTIONS)

PD (Democratic Party) leader Pierluigi Bersani (L) embraces PDL (People of freedom party) secretary Angelino Alfano during the presidential election in the lower house of the parliament in Rome April 18, 2013. Italy's divided parliament begins voting for a new state president on Thursday, with former Senate Speaker Franco Marini the main candidate in a ballot that will severely strain the unity of the centre-left alliance led by Pier Luigi Bersani. The vote for a successor to President Giorgio Napolitano, whose term ends on May 15, will be a crucial step towards resolving the stalemate since the inconclusive election in February left no party with enough support to form a government. REUTERS/Tony Gentile (ITALY - Tags: POLITICS ELECTIONS)

5-Star Movement group Roberta Lombardi casts her ballot during the presidential election in the lower house of the parliament in Rome April 18, 2013. Italy's divided parliament begins voting for a new state president on Thursday, with former Senate Speaker Franco Marini the main candidate in a ballot that will severely strain the unity of the centre-left alliance led by Pier Luigi Bersani. The vote for a successor to President Giorgio Napolitano, whose term ends on May 15, will be a crucial step towards resolving the stalemate since the inconclusive election in February left no party with enough support to form a government. REUTERS/Tony Gentile (ITALY - Tags: POLITICS ELECTIONS)

Italy's former Prime Minister Silvio Berlusconi (L) shakes hands with upper house President Pietro Grasso during the presidential election in the lower house of the parliament in Rome April 18, 2013. Italy's divided parliament begins voting for a new state president on Thursday, with former Senate Speaker Franco Marini the main candidate in a ballot that will severely strain the unity of the centre-left alliance led by Pier Luigi Bersani. The vote for a successor to President Giorgio Napolitano, whose term ends on May 15, will be a crucial step towards resolving the stalemate since the inconclusive election in February left no party with enough support to form a government. REUTERS/Tony Gentile (ITALY - Tags: POLITICS ELECTIONS)

Italy's former Prime Minister Silvio Berlusconi (2nd R) shakes hands with the lower house President Laura Boldrini during presidential election in the lower house of the parliament in Rome April 18, 2013. Italy's divided parliament begins voting for a new state president on Thursday, with former Senate Speaker Franco Marini the main candidate in a ballot that will severely strain the unity of the centre-left alliance led by Pier Luigi Bersani. The vote for a successor to President Giorgio Napolitano, whose term ends on May 15, will be a crucial step towards resolving the stalemate since the inconclusive election in February left no party with enough support to form a government. REUTERS/Tony Gentile (ITALY - Tags: POLITICS ELECTIONS)

The lower house of the parliament is seen during the presidential election in Rome April 18, 2013. Italy's divided parliament begins voting for a new state president on Thursday, with former Senate Speaker Franco Marini the main candidate in a ballot that will severely strain the unity of the centre-left alliance led by Pier Luigi Bersani. The vote for a successor to President Giorgio Napolitano, whose term ends on May 15, will be a crucial step towards resolving the stalemate since the inconclusive election in February left no party with enough support to form a government. REUTERS/Tony Gentile (ITALY - Tags: POLITICS ELECTIONS)

PD (Democratic Party) leader Pierluigi Bersani (2nd L) smiles during the presidential election in the lower house of the parliament in Rome April 18, 2013. Italy's divided parliament begins voting for a new state president on Thursday, with former Senate Speaker Franco Marini the main candidate in a ballot that will severely strain the unity of the centre-left alliance led by Pier Luigi Bersani. The vote for a successor to President Giorgio Napolitano, whose term ends on May 15, will be a crucial step towards resolving the stalemate since the inconclusive election in February left no party with enough support to form a government. REUTERS/Tony Gentile (ITALY - Tags: POLITICS ELECTIONS)

PD (Democratic Party) leader Pierluigi Bersani holds his ballot during the presidential election in the lower house of the parliament in Rome April 18, 2013. Italy's divided parliament begins voting for a new state president on Thursday, with former Senate Speaker Franco Marini the main candidate in a ballot that will severely strain the unity of the centre-left alliance led by Pier Luigi Bersani. The vote for a successor to President Giorgio Napolitano, whose term ends on May 15, will be a crucial step towards resolving the stalemate since the inconclusive election in February left no party with enough support to form a government. REUTERS/Tony Gentile (ITALY - Tags: POLITICS ELECTIONS)

PD (Democratic Party) leader Pierluigi Bersani holds his ballot during the presidential election in the lower house of the parliament in Rome April 18, 2013. Italy's divided parliament begins voting for a new state president on Thursday, with former Senate Speaker Franco Marini the main candidate in a ballot that will severely strain the unity of the centre-left alliance led by Pier Luigi Bersani. The vote for a successor to President Giorgio Napolitano, whose term ends on May 15, will be a crucial step towards resolving the stalemate since the inconclusive election in February left no party with enough support to form a government. REUTERS/Tony Gentile (ITALY - Tags: POLITICS ELECTIONS)

PD (Democratic Party) leader Pierluigi Bersani (R) embraces PDL (People of freedom party) secretary Angelino Alfano during the presidential election in the lower house of the parliament in Rome April 18, 2013. Italy's divided parliament begins voting for a new state president on Thursday, with former Senate Speaker Franco Marini the main candidate in a ballot that will severely strain the unity of the centre-left alliance led by Pier Luigi Bersani. The vote for a successor to President Giorgio Napolitano, whose term ends on May 15, will be a crucial step towards resolving the stalemate since the inconclusive election in February left no party with enough support to form a government. REUTERS/Tony Gentile (ITALY - Tags: POLITICS ELECTIONS)

PD (Democratic Party) leader Pierluigi Bersani (L) embraces PDL (People of freedom party) secretary Angelino Alfano during the presidential election in the lower house of the parliament in Rome April 18, 2013. Italy's divided parliament begins voting for a new state president on Thursday, with former Senate Speaker Franco Marini the main candidate in a ballot that will severely strain the unity of the centre-left alliance led by Pier Luigi Bersani. The vote for a successor to President Giorgio Napolitano, whose term ends on May 15, will be a crucial step towards resolving the stalemate since the inconclusive election in February left no party with enough support to form a government. REUTERS/Tony Gentile (ITALY - Tags: POLITICS ELECTIONS)

Italy's former Prime Minister Silvio Berlusconi (R) attends the presidential election in the lower house of the parliament in Rome April 18, 2013. Italy's divided parliament begins voting for a new state president on Thursday, with former Senate Speaker Franco Marini the main candidate in a ballot that will severely strain the unity of the centre-left alliance led by Pier Luigi Bersani. The vote for a successor to President Giorgio Napolitano, whose term ends on May 15, will be a crucial step towards resolving the stalemate since the inconclusive election in February left no party with enough support to form a government. REUTERS/Tony Gentile (ITALY - Tags: POLITICS ELECTIONS)

PD (Democratic Party) leader Pierluigi Bersani casts his ballot during the presidential election in the lower house of the parliament in Rome April 18, 2013. Italy's divided parliament begins voting for a new state president on Thursday, with former Senate Speaker Franco Marini the main candidate in a ballot that will severely strain the unity of the centre-left alliance led by Pier Luigi Bersani. The vote for a successor to President Giorgio Napolitano, whose term ends on May 15, will be a crucial step towards resolving the stalemate since the inconclusive election in February left no party with enough support to form a government. REUTERS/Tony Gentile (ITALY - Tags: POLITICS ELECTIONS)

Italy's former Prime Minister Silvio Berlusconi enters the polling booths during the presidential election in the lower house of the parliament in Rome April 18, 2013. Italy's divided parliament begins voting for a new state president on Thursday, with former Senate Speaker Franco Marini the main candidate in a ballot that will severely strain the unity of the centre-left alliance led by Pier Luigi Bersani. The vote for a successor to President Giorgio Napolitano, whose term ends on May 15, will be a crucial step towards resolving the stalemate since the inconclusive election in February left no party with enough support to form a government. REUTERS/Tony Gentile (ITALY - Tags: POLITICS ELECTIONS)

Italy's former Prime Minister Silvio Berlusconi casts his ballot during the presidential election in the lower house of the parliament in Rome April 18, 2013. Italy's divided parliament begins voting for a new state president on Thursday, with former Senate Speaker Franco Marini the main candidate in a ballot that will severely strain the unity of the centre-left alliance led by Pier Luigi Bersani. The vote for a successor to President Giorgio Napolitano, whose term ends on May 15, will be a crucial step towards resolving the stalemate since the inconclusive election in February left no party with enough support to form a government. REUTERS/Tony Gentile (ITALY - Tags: POLITICS ELECTIONS)

A member of parliament casts his ballot during the presidential election in the lower house of the parliament in Rome April 18, 2013. Italy's divided parliament begins voting for a new state president on Thursday, with former Senate Speaker Franco Marini the main candidate in a ballot that will severely strain the unity of the centre-left alliance led by Pier Luigi Bersani. The vote for a successor to President Giorgio Napolitano, whose term ends on May 15, will be a crucial step towards resolving the stalemate since the inconclusive election in February left no party with enough support to form a government. REUTERS/Tony Gentile (ITALY - Tags: POLITICS ELECTIONS)

Alessandra Mussolini, the granddaughter of Italian wartime dictator Benito Mussolini, casts her ballot during the presidential election in the lower house of the parliament in Rome April 18, 2013. Italy's divided parliament begins voting for a new state president on Thursday, with former Senate Speaker Franco Marini the main candidate in a ballot that will severely strain the unity of the centre-left alliance led by Pier Luigi Bersani. The vote for a successor to President Giorgio Napolitano, whose term ends on May 15, will be a crucial step towards resolving the stalemate since the inconclusive election in February left no party with enough support to form a government. REUTERS/Tony Gentile (ITALY - Tags: POLITICS ELECTIONS)

PD (Democratic Party) leader Angela Finocchiaro casts her ballot during the presidential election in the lower house of the parliament in Rome April 18, 2013. Italy's divided parliament begins voting for a new state president on Thursday, with former Senate Speaker Franco Marini the main candidate in a ballot that will severely strain the unity of the centre-left alliance led by Pier Luigi Bersani. The vote for a successor to President Giorgio Napolitano, whose term ends on May 15, will be a crucial step towards resolving the stalemate since the inconclusive election in February left no party with enough support to form a government. REUTERS/Tony Gentile (ITALY - Tags: POLITICS ELECTIONS)

Upper house President Pietro Grasso (L) and his lower house counterpart Laura Boldrini look on during the presidential election in the lower house of the parliament in Rome April 18, 2013. Italy's divided parliament begins voting for a new state president on Thursday, with former Senate Speaker Franco Marini the main candidate in a ballot that will severely strain the unity of the centre-left alliance led by Pier Luigi Bersani. The vote for a successor to President Giorgio Napolitano, whose term ends on May 15, will be a crucial step towards resolving the stalemate since the inconclusive election in February left no party with enough support to form a government. REUTERS/Tony Gentile (ITALY - Tags: POLITICS ELECTIONS)

Vito Crimi, head of the 5-Star Movement group at the upper house, casts his ballot during the presidential election in the lower house of the parliament in Rome April 18, 2013. Italy's divided parliament begins voting for a new state president on Thursday, with former Senate Speaker Franco Marini the main candidate in a ballot that will severely strain the unity of the centre-left alliance led by Pier Luigi Bersani. The vote for a successor to President Giorgio Napolitano, whose term ends on May 15, will be a crucial step towards resolving the stalemate since the inconclusive election in February left no party with enough support to form a government. REUTERS/Tony Gentile (ITALY - Tags: POLITICS ELECTIONS)

A member of parliament casts his ballot during the presidential election in the lower house of the parliament in Rome April 18, 2013. Italy's divided parliament begins voting for a new state president on Thursday, with former Senate Speaker Franco Marini the main candidate in a ballot that will severely strain the unity of the centre-left alliance led by Pier Luigi Bersani. The vote for a successor to President Giorgio Napolitano, whose term ends on May 15, will be a crucial step towards resolving the stalemate since the inconclusive election in February left no party with enough support to form a government. REUTERS/Tony Gentile (ITALY - Tags: POLITICS ELECTIONS)

Italian Prime Minister Mario Monti holds his ballot during the presidential election in the lower house of the parliament in Rome April 18, 2013. Italy's divided parliament begins voting for a new state president on Thursday, with former Senate Speaker Franco Marini the main candidate in a ballot that will severely strain the unity of the centre-left alliance led by Pier Luigi Bersani. The vote for a successor to President Giorgio Napolitano, whose term ends on May 15, will be a crucial step towards resolving the stalemate since the inconclusive election in February left no party with enough support to form a government. REUTERS/Tony Gentile (ITALY - Tags: POLITICS ELECTIONS)

Italian Prime Minister Mario Monti casts his ballot during the presidential election in the lower house of the parliament in Rome April 18, 2013. Italy's divided parliament begins voting for a new state president on Thursday, with former Senate Speaker Franco Marini the main candidate in a ballot that will severely strain the unity of the centre-left alliance led by Pier Luigi Bersani. The vote for a successor to President Giorgio Napolitano, whose term ends on May 15, will be a crucial step towards resolving the stalemate since the inconclusive election in February left no party with enough support to form a government. REUTERS/Tony Gentile (ITALY - Tags: POLITICS ELECTIONS)

The lower house of the parliament is seen before the start of the vote for the new president in Rome April 18, 2013. Italy's divided parliament begins voting for a new state president today, with former Senate Speaker Franco Marini the main candidate in a ballot that will severely strain the unity of the centre-left alliance led by Pier Luigi Bersani. The vote for a successor to President Giorgio Napolitano, whose term ends on May 15, will be a crucial step towards resolving the stalemate since the inconclusive election in February left no party with enough support to form a government. REUTERS/Tony Gentile (ITALY - Tags: POLITICS ELECTIONS)

Ballot boxes for the Italian presidential election are seen in the lower house of the parliament in Rome April 18, 2013. Italy's divided parliament begins voting for a new state president today, with former Senate Speaker Franco Marini the main candidate in a ballot that will severely strain the unity of the centre-left alliance led by Pier Luigi Bersani. The vote for a successor to President Giorgio Napolitano, whose term ends on May 15, will be a crucial step towards resolving the stalemate since the inconclusive election in February left no party with enough support to form a government. REUTERS/Tony Gentile (ITALY - Tags: POLITICS ELECTIONS)

Democratic Party (PD) and centre-left leader Pier Luigi Bersani's deputy Enrico Letta speaks with the media after meeting Italy's President Giorgio Napolitano at Quirinale Palace in Rome March 29, 2013. Italy remained in political deadlock on Friday after a new round of talks led by Napolitano failed to break the stalemate created by elections last month that left no group able to form a government alone. REUTERS/Remo Casilli (ITALY - Tags: POLITICS)

Democratic Party (PD) and centre-left leader Pier Luigi Bersani's deputy Enrico Letta speaks with the media after meeting Italy's President Giorgio Napolitano at Quirinale Palace in Rome March 29, 2013. Italy remained in political deadlock on Friday after a new round of talks led by Napolitano failed to break the stalemate created by elections last month that left no group able to form a government alone. REUTERS/Remo Casilli (ITALY - Tags: POLITICS)

Italy's Northern League secretary Roberto Maroni (C) talks during a news conference, in front of former Italian Prime Minister Silvio Berlusconi (R), following a meeting with Italian President Giorgio Napolitano at Quirinale Palace in Rome March 29, 2013. Berlusconi said on Friday he was ready to support a coalition government with centre-left leader Pier Luigi Bersani but rejected another technocrat administration like the outgoing one led by Mario Monti. REUTERS/Stefano Rellandini(ITALY - Tags: POLITICS ELECTIONS BUSINESS)

Italian centre-left leader Pier Luigi Bersani speaks after meeting with Italian President Giorgio Napolitano at Quirinale palace in Rome March 21, 2013. Italian centre-left leader Pier Luigi Bersani on Thursday appealed to all the parties in parliament to be responsible and back a new government that can pass the reforms the country needs. REUTERS/Remo Casilli (ITALY - Tags: POLITICS)

Italian centre-left leader Pier Luigi Bersani speaks after meeting with Italian President Giorgio Napolitano at Quirinale palace in Rome March 21, 2013. Italian centre-left leader Pier Luigi Bersani on Thursday appealed to all the parties in parliament to be responsible and back a new government that can pass the reforms the country needs. REUTERS/Remo Casilli (ITALY - Tags: POLITICS)

Italian centre-left leader Pier Luigi Bersani speaks after meeting with Italian President Giorgio Napolitano at Quirinale palace in Rome March 21, 2013. Italian centre-left leader Pier Luigi Bersani on Thursday appealed to all the parties in parliament to be responsible and back a new government that can pass the reforms the country needs. REUTERS/Remo Casilli (ITALY - Tags: POLITICS)

Italian centre-left leader Pier Luigi Bersani leaves after meeting with Italian President Giorgio Napolitano at Quirinale palace in Rome March 21, 2013. Italian centre-left leader Pier Luigi Bersani on Thursday appealed to all the parties in parliament to be responsible and back a new government that can pass the reforms the country needs. REUTERS/Remo Casilli (ITALY - Tags: POLITICS)

Italian PD (Democratic Party) leader Pier Luigi Bersani leaves at the end of a news conference in Rome February 26, 2013. Italy's stunned political parties looked for a way forward on Tuesday after an election that gave none of them a parliamentary majority, posing the threat of prolonged instability and European financial crisis. The results, notably by the dramatic surge of the anti-establishment 5-Star Movement of comic Beppe Grillo, left the centre-left bloc with a majority in the lower house but without the numbers to control the powerful upper chamber, the Senate. REUTERS/Tony Gentile (ITALY - Tags: POLITICS ELECTIONS BUSINESS)

Italian PD (Democratic Party) leader Pier Luigi Bersani speaks during a news conference in Rome February 26, 2013. Italy's stunned political parties looked for a way forward on Tuesday after an election that gave none of them a parliamentary majority, posing the threat of prolonged instability and European financial crisis. The results, notably by the dramatic surge of the anti-establishment 5-Star Movement of comic Beppe Grillo, left the centre-left bloc with a majority in the lower house but without the numbers to control the powerful upper chamber, the Senate. REUTERS/Tony Gentile (ITALY - Tags: POLITICS ELECTIONS BUSINESS)

Italian PD (Democratic Party) leader Pier Luigi Bersani reacts during a news conference in Rome February 26, 2013. Italy's stunned political parties looked for a way forward on Tuesday after an election that gave none of them a parliamentary majority, posing the threat of prolonged instability and European financial crisis. The results, notably by the dramatic surge of the anti-establishment 5-Star Movement of comic Beppe Grillo, left the centre-left bloc with a majority in the lower house but without the numbers to control the powerful upper chamber, the Senate. REUTERS/Tony Gentile (ITALY - Tags: POLITICS ELECTIONS)

Italian PD (Democratic Party) leader Pier Luigi Bersani reacts during a news conference in Rome February 26, 2013. Italy's stunned political parties looked for a way forward on Tuesday after an election that gave none of them a parliamentary majority, posing the threat of prolonged instability and European financial crisis. The results, notably by the dramatic surge of the anti-establishment 5-Star Movement of comic Beppe Grillo, left the centre-left bloc with a majority in the lower house but without the numbers to control the powerful upper chamber, the Senate. REUTERS/Tony Gentile (ITALY - Tags: POLITICS ELECTIONS TPX IMAGES OF THE DAY)

Italian PD (Democratic Party) leader Pier Luigi Bersani speaks during a news conference in Rome February 26, 2013. Italy's stunned political parties looked for a way forward on Tuesday after an election that gave none of them a parliamentary majority, posing the threat of prolonged instability and European financial crisis. The results, notably by the dramatic surge of the anti-establishment 5-Star Movement of comic Beppe Grillo, left the centre-left bloc with a majority in the lower house but without the numbers to control the powerful upper chamber, the Senate. REUTERS/Tony Gentile (ITALY - Tags: POLITICS ELECTIONS)

Italian PD (Democratic Party) leader Pier Luigi Bersani speaks during a news conference in Rome February 26, 2013. Italy's stunned political parties looked for a way forward on Tuesday after an election that gave none of them a parliamentary majority, posing the threat of prolonged instability and European financial crisis. The results, notably by the dramatic surge of the anti-establishment 5-Star Movement of comic Beppe Grillo, left the centre-left bloc with a majority in the lower house but without the numbers to control the powerful upper chamber, the Senate. REUTERS/Tony Gentile (ITALY - Tags: POLITICS ELECTIONS)

Italian PD (Democratic Party) leader Pier Luigi Bersani speaks during a news conference in Rome February 26, 2013. Italy's stunned political parties looked for a way forward on Tuesday after an election that gave none of them a parliamentary majority, posing the threat of prolonged instability and European financial crisis. The results, notably by the dramatic surge of the anti-establishment 5-Star Movement of comic Beppe Grillo, left the centre-left bloc with a majority in the lower house but without the numbers to control the powerful upper chamber, the Senate. REUTERS/Tony Gentile (ITALY - Tags: POLITICS ELECTIONS HEADSHOT)

Italian PD (Democratic Party) leader Pier Luigi Bersani speaks during a news conference in Rome February 26, 2013. Italy's stunned political parties looked for a way forward on Tuesday after an election that gave none of them a parliamentary majority, posing the threat of prolonged instability and European financial crisis. The results, notably by the dramatic surge of the anti-establishment 5-Star Movement of comic Beppe Grillo, left the centre-left bloc with a majority in the lower house but without the numbers to control the powerful upper chamber, the Senate. REUTERS/Tony Gentile (ITALY - Tags: POLITICS ELECTIONS)