Israeli Prime Minister Benjamin Netanyahu's ruling Likud party on Monday approved an electoral pact with the ultranationalist Yisrael Beitenu, overcoming internal opposition within Likud.
Opponents of the temporary alliance for the January general election failed in their bid to have the matter decided by secret ballot and the motion passed by an overwhelming show of hands, an AFP correspondent said.
"In the face of the security and financial challenges we need unity and responsibility," Netanyahu told members of the Likud's governing central committee convened in Tel Aviv to vote on his proposal for a partnership with the far-right party headed by Foreign Minister Avigdor Lieberman.
"At this time, it's essential that national camp unites forces. That's why I asked Lieberman to run with the Likud," he said.
Netanyahu stressed that his party would remain independent, and "continue our way in preserving our security, heritage, economy."
Likud holds 27 of the 120 seats in the outgoing Knesset, or parliament, while Lieberman's Yisrael Beitenu has 15 seats.
Polls predict that working as a team will give them at least as many members in the next parliament and probably more.
Internal opposition to the plan was led by Public Services Minister Michael Eitan, who called it "a mistake that will undermine Likud" -- but his bid to have it put to a secret ballot failed to garner support from the needed 10 percent of the delegates.
As the party faithful were herded on Monday evening through tight security at a conference centre in northern Tel Aviv, Eitan and a number of aides were seen scrambling to obtain the necessary signatures.
Even those strongly against the merger were hesitant about visibly defying Netanyahu, who looks set to be easily re-elected as premier in January.
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"I'm opposed to the deal with Lieberman, but don't want to embarrass Netanyahu by voting against him," a Likud official told AFP, speaking on condition of anonymity.
"With a heavy heart, I'll vote in favour."
Yehuda Glick, who is hoping to win a spot on the parliamentary candidates' list as Likud's representative for West Bank settlements, said the merger was "an excellent idea."
"It's time to unite fragments of parties -- you can't have a party for every fragment of an idea," said the US-born Knesset hopeful.
"The Likud is a broad home with room for lots of ideas. That's why I joined." US political guru Arthur Finkelstein, who was involved in drafting the proposal, said a joint list would give them at least the 42 seats they collectively hold, with the likelihood of an additional two or three.
But several surveys suggested the joint list would not pick up many more seats, and could even drop.
A poll published on Monday in the Maariv daily predicted the alliance would get 43 seats, with the opposition Labour party coming a distant second with 20.
Another survey broadcast on Sunday evening by commercial TV station Channel 2 gave the partnership 42 seats, with 23 for Labour.
And a third survey released on Sunday night by private broadcaster Channel 10 gave only 35 seats to the so-called "Bieberman" alliance -- a fusion of Lieberman and 'Bibi' Netanyahu -- with Labour picking up 23.
Pollsters see the main opposition Kadima party, the largest faction in parliament with 28 seats, plunging into oblivion, with Maariv giving it only four seats in the next Knesset.