JERUSALEM — Israel's parliament passed a bill Monday that could complicate peace efforts with the Palestinians and Syria by making it very difficult for any government to make territorial withdrawals.

The bill requires a two-thirds Knesset majority to cede land in east Jerusalem to the Palestinians or in the Golan Heights to Syria. Failing that, either withdrawal would become subject to a referendum, and polls show winning public approval would be an uphill battle.

The bill — which passed by a 65-33 majority — will have little impact in the short term, since neither deal seems imminent. But it reflects growing jitters by hard-liners in parliament — especially over U.S. efforts to forge a peace agreement between Israel and the Palestinians.

Prime Minister Benjamin Netanyahu's own position seems influenced by his need to appease his voter base while preventing the collapse of the peace process — which would anger the Israeli center, alienate America and risk new violence. On Monday, he voted along with the hard-liners.

"Any peace agreement requires national agreement and the bill promises that," he said in a statement. "The Israeli public is involved, aware and responsible and I trust that when the day comes it will support a peace agreement that answers the national interests and security needs of the state of Israel."

The Palestinian government in the West Bank, which refuses to negotiate without a freeze on new Jewish construction in the West Bank and east Jerusalem, condemned the bill.

"With the passage of this bill, the Israeli leadership, yet again, is making a mockery of international law," said Palestinian negotiator Saeb Erekat. "Ending the occupation of our land is not and cannot be dependent on any sort of referendum."

There was no comment from Syria, which lost the Golan Heights to Israel in the 1967 war and wants it all back as the price for peace. Talk of withdrawal is hugely unpopular in Israel, where the heights, which overlook northern Israel, are considered a strategic asset.

With the Syrian negotiations stalled for years, the more acute issue appeared to be east Jerusalem — which Israel also seized in 1967 and which the Palestinians want for their capital.

Israel swiftly annexed the Arab core of the city and has surrounded it with a series of communities to solidify its control. Israelis tend to view these as mere Jewish neighborhoods of the capital — while Palestinians liken them to the West Bank settlements they revile.

Israeli governments over the years have wrestled with how to meet Palestinian demands, which would mean giving up control of one of the world's most coveted historical areas — Jerusalem's Old City — within a stone's throw from Israel's centers of government. Now, the referendum bill would make it even more difficult.

By requiring a two-thirds majority, the law raises the bar for passage. It would also mean that only a rightist government — one that could depend on opposition support — could ever reach such a deal.

Rightist-authored peace deals are less likely but not without precedent: Israel's historic 1979 peace agreement with Egypt was passed in parliament by a 95-18 margin, sponsored by the nationalist government of Menachem Begin.

More recently, the interim Oslo peace accords between Israel and the Palestinians in the 1990s, reached by the center-left government of Yitzhak Rabin, passed by the slimmest of majorities.

Going to the Israeli public if the parliament vote should fail could be equally difficult.

"Israel has gone back to having a majority of people who view peace as a dangerous trap that the Arabs ... are laying at the feet of weak politicians," wrote respected columnist Akiva Eldar in the Haaretz daily.

Polls tend to show most Israelis oppose ceding the Old City, where Judaism's holiest site shares the same hilltop compound as the Al-Aqsa mosque, the third-holiest site in Islam — both a short walk from a focal point of Christianity at the Church of the Holy Sepulcher.

"There is no doubt that this is a dramatic piece of legislation for the people of Israel and the state of Israel," the bill's sponsor, Yariv Levin of Netanyahu's Likud Party, said before the deliberations began. "The law determines that peace must be made between peoples and not just between leaders."

That Netanyahu allowed a junior member of the coalition to push through so critical a bill probably reflects his own ambivalence toward President Barack Obama's peace push — and the peace enterprise in general.