By Steve Scherer and Francesca Piscioneri
ROME (Reuters) - Italy's president began talks with political leaders on Thursday to seek a way out of the political crisis caused by the resignation of Prime Minister Matteo Renzi.
Sergio Mattarella, a 75-year-old former constitutional court judge, must decide if someone can lead Italy to elections scheduled for 2018, or whether an interim government should serve until a snap vote can be held in spring.
Renzi tendered his resignation on Wednesday after a bruising defeat in a referendum on which he had staked his political future.
Mattarella's first consultations were with the leaders of both houses of parliament, and neither commented afterwards.
Mattarella, a former Christian Democrat, also met with his more interventioniest predecessor, 91-year-old Giorgio Napolitano, who asked Renzi to form a government in 2014. Napolitano also did not comment.
Meetings will expand to parliamentary parties on Friday and wrap up on Saturday evening.
The process is a familiar one in Italy, which has a notorious history of government collapses, but it is the first since the Sicilian Mattarella took office last year after a career in politics which began after the mafia assassinated his politician brother in 1980.
Mattarella could wait until Monday to make his decision known, a source close to the president said. Renzi has ruled out -- for the moment -- staying on as a caretaker, a parliamentary source said.
Most parties, including Renzi's Democratic Party (PD) which holds the most seats in parliament, appear to favor an early vote, which would add Italy to a list of major European countries - including France, Germany and the Netherlands - facing a national ballot in 2017.
So far markets have taken Italy's political turmoil in their stride. Even Banca Monte dei Paschi di Siena, which looks likely to require government intervention to survive, saw its shares close up more than 4 percent on Thursday after it asked the European Central Bank for a three-week extension to its rescue plan.
On Tuesday, Mattarella unexpectedly dictated two conditions that delay any vote until spring: the Constitutional Court must rule on the lower house's current voting law, a decision not expected before a Jan. 24.
Subsequently parliament must draft new election rules for both houses, Mattarella indicated. Considering 45 days for campaigning are set aside by law, it would be difficult to hold an election before April.
The consultations allow Mattarella to test parliamentary waters, but Renzi's majority - and his input as leader of the PD - are key to what happens next.
On Wednesday, Renzi said the PD would only participate in a government intended to last until 2018 if it was backed by the main forces in parliament, a prospect most of them have already ruled out. Otherwise, early elections should be held as soon as possible, he said.
The rightist Northern League and anti-establishment 5-Star Movement renewed calls for immediate elections on Thursday.
Because of the strong push for an early vote, Mattarella is widely expected to ask a member of Renzi's cabinet, or a politician from his Democratic Party, to put together an interim government.
(Additional reporting by Antonella Cinelli. Editing by Robin Pomeroy and Richard Lough)