By Allyn Fisher-Ilan
JERUSALEM (Reuters) - Former Israeli justice minister Tzipi Livni and the center-left parliamentary opposition leader formed a joint election ticket on Wednesday that polls show could pose a serious challenge to Prime Minister Benjamin Netanyahu in March.
After months of infighting over Israel's handling of stalled U.S.-sponsored peace talks with the Palestinians, the 2015 state budget and nationalist legislation, Netanyahu last week fired Livni from his cabinet, in effect ending the conservative governing coalition in favor of an early election.
"I am here to create the force-multiplier that will change the government in the State of Israel," Livni told a televised news conference alongside Isaac Herzog of the Labour party.
Polls have predicted Netanyahu's rightist Likud party winning the vote called for March 17, with around 22 of parliament's 120 seats. Running separately, Labour and Livni's centrist Hatnuah party were seen trailing Likud.
But a Dec. 4 survey by the Globes newspaper and a Dec. 7 poll by the parliamentary television channel found that a joint Herzog-Livni list would edge the incumbent with 23 or 24 seats.
Herzog told reporters that, should they form the next government, he would serve as prime minister for the first half of the term and would rotate the role to Livni for the second.
"In the last election, two years ago, the centrist camp did not manage to stick together," Herzog said. "I promised to myself the day I was elected to head the Labour party that this time it will not happen - not on my watch."
He pledged to roll back Israel's international isolation over the Palestinian deadlock and nationalist policies and bring "security instead of fear, dialogue instead of hatred".
Some commentators doubted whether the alliance would work. Livni, originally a Likud member, has switched parties three times since 2005 and failed three times to secure the premiership.
Her latest move is to a party seen more as left-leaning than centrist in a country where hawkish sentiment seems dominant as regional security threats have proliferated.
"Extremists have taken over all the good prospects - all the good prospects of the Likud, which was once my home," Livni said. "They are turning our country into an isolated, boxed-in country, and an alienating one - even for its own citizens."
Despite the threatening unity bid by his competitors, Netanyahu won a boost from inside his own party on Wednesday when Likud's decision-making central committee endorsed his call to move up a leadership contest to Dec. 31.
Likud's plans to vote for a prime ministerial candidate had been scheduled for Jan. 6. Netanyahu hopes an earlier contest will keep an ex cabinet minister, Gideon Sa'ar, seen as a serious potential rival, out of the race. Netanyahu would then face off against two less-popular politicians.
Some 65 percent of Likud committee members passed Netanyahu's motion in a secret ballot, a party spokeswoman said after the ballots were counted late on Wednesday night.
(Writing by Dan Williams; Editing by Mark Heinrich and David Gregorio)