Italy’s political deadlock deepened over the selection of the next president, raising the threat of snap elections after Democratic Party lawmakers refused orders to back a compromise candidate.

Party head Pier Luigi Bersani signaled he will abandon his nominee, Franco Marini, after his allies rebelled over the choice, leading to two failed ballots yesterday. Voting resumes Friday at 10 a.m. in Rome.

“This challenge of keeping the party together is clearly growing more acute,” said Peter Ceretti, a Eurasia Group analyst in New York. “If a consensus candidate can’t be elected politically things become much more uncertain.”

The political wrangling spilled into the streets outside of Rome’s Chamber of Deputies where protesters denounced Bersani for embracing his traditional rival, Silvio Berlusconi, in the bid to install Marini as a first step to a possible coalition government. Inside the lower house of parliament, backbenchers from the Democratic Party, or PD, openly flouted their marching orders.

“Marini was a big mistake on the part of Bersani’s,” said Gemma Scarselli, a 38-year-old public administration employee and a PD voter, as she protested outside the Chamber. “An alliance with Berlusconi is a step backwards that I personally did not appreciate.”

Fourth Round

Secret ballots are cast one by one in a process that typically allows for only two votes a day. The threshold of a simple majority will be imposed from the fourth round, meaning that the initial vote Friday morning will be the final one with a two-thirds requirement.

The Italian parliament has been reduced to near-paralysis by an inconclusive general election in February and Bersani’s inability to entice rivals into backing his bid to replace Prime Minister Mario Monti’s caretaker government. The presidential election gave the 61-year-old former communist an opportunity to find common ground with adversaries and set the stage for a government deal. The Democratic Party revolt weakens his hand.

Berlusconi, a three-time premier and head of the second- biggest contingent of lawmakers, said late Thursday at a rally in Udine he would push for snap elections in June if lawmakers are unable to form a strong government. Officials of his party mocked Bersani, whose leads the largest coalition in parliament, for not exacting discipline.

A ‘Tragedy’

“The PD isn’t a party, it’s a tragedy,” Maurizio Gasparri, a senator and former communication’s minister under Berlusconi, said to reporters.

The yield on Italian 10-year bonds rose 1 basis point to 4.26 percent Thursday, widening the difference between yields on similar maturity German bunds 1 basis point to 3.03 percent.

The next head of state, who will succeed President Giorgio Napolitano, 87, will become the key figure in the effort to resolve the political impasse. The president appoints the prime minister and, when stalemates prove intractable, dissolves parliament and calls new elections.

Marini, an ex-Senate speaker from the PD, was the top vote getter in the first round yesterday with 521 votes, more than twice that of former lawmaker Stefano Rodota, the candidate of Beppe Grillo’s Five Star Movement. The PD and Berlusconi’s People of Liberty party cast blank ballots in the second round when it became obvious Marini wouldn’t get the 672 votes needed for a two-thirds majority.

The PD and People of Liberty, or PDL, were thrown together by the emergence of Grillo, an ex-comic and anti-corruption crusader who won a blocking minority in the February elections. Five Star, which refused to support Bersani’s bid for the premiership last month, campaigned against political scandals and says its aim is to sweep established lawmakers from power.