The Knesset passed into law on Monday a bill conditioning any retreat from territories Israel considers to be under its sovereignty upon the holding of a popular referendum.

The bill, proposed by House Committee chairman Yariv Levin (Likud ), sets downs the rules for such a referendum, which would be required in the case of an Israeli pullback from the Golan Heights or East Jerusalem, though not in the West Bank, which has not been annexed to Israel. It comes as an amendment to the existing referendums law.

The bill passed with 65 MKs approving, 33 opposing, with the rest absent or abstaining.

"This is a bill of the utmost national importance for retaining the unity of the people," MK Levin said prior to the vote

"The bill expresses the need to ensure that any fateful, irreversible decision on giving up parts of the homeland on which the state's sovereignty has been enacted, will no longer be done through wheeling and dealing and recruiting parliamentary support through other issues, as has happened sadly in the past."

Last December, 68 MKs, including Labor chairman Ehud Barak and Likud minister Dan Meridor, supported the bill. Twenty-two MKs, including opposition chair Tzipi Livni, opposed it. Barak claimed at the time that he was opposed to the bill, but that if Meretz would make the vote into a confidence vote on the government, Labor would have to vote in favor.

He said at the time that the bill was unnecessary because it places unnecessary constraints on the prime minister, should he decide to negotiate with Syria, and that the constitutional implications of such a referendum meant the subject was better left for a Basic Law applying to other areas as well.

Voicing her objection to the bill, opposition leader Livni said earlier Monday that Netanyahu was attempting to pass on the decision of whether or not to relinquish land as part of a future peace deal since he is too weak to make that decision himself.

Referring to the upcoming vote, Livni said that her party, Kadima, would vote against the bill, saying that the issue at hand was essential, one which has "nothing to do with who wants or doesn't want to give up portions of Israel."

"Those are the kind of decisions taken by a leadership which understands the gravity of the issues at hand, from all sides," Livni said, adding she felt Netanyahu was "a weak prime minister" who was comfortable with passing on responsibility.

The Kadima leader added that any decision of the kind the bill discussed "would be tied to considerations that are not always made public, and then the public is expected to understand everything."

"It has nothing to do with right-wing or left-wing but on decision making in a democracy, where there is only one referendum and that's a general election," Livni said, adding that the premier "should say the same things both before and after those elections."