Israel's prime minister, Ariel Sharon, meets President Bush in Washington this week, hoping to win support for his plan to unilaterally pull out of Palestinian areas. He hopes U.S. support will help win him domestic support for the plan, as well.
His meeting with President Bush, set for Wednesday at the White House, effectively marks the start of a mini-election campaign for Mr. Sharon, which could decide whether he will remain Israel's prime minister.
Mr. Sharon is banking on a big commitment from Mr. Bush to help him win enough votes in his ruling Likud party, whose 200,000 members vote in a referendum on his unilateral plan in early May.
Under the Sharon plan, Israel would unilaterally withdraw troops and Jewish settlements from the Gaza Strip. Four settlements in the West Bank would also be dismantled.
If Mr. Sharon wins the Likud referendum, the plan would swiftly be put to his cabinet and then to the Israeli parliament for approval.
But Mr. Sharon's decision to turn to the U.S. president for support on what others see as a domestic matter has angered some in the Israeli Cabinet.
"With all due respect, you cannot go and negotiate [the fate of Israel] in the United States of America," said Benny Elon, tourism minister. "It is a sin, it is Zionist Jewish sin of uprooting Jews in Eretz [the Land of] Israel without the authorization of the government."
Mr. Elon says he and other members of his National Union faction will pull out of the government, if Mr. Sharon's plan is implemented.
But others, such as Yuval Steinitz, the head of the Israeli parliamentary foreign affairs and defense committee, and himself a member of the Likud Party, disagree.
"Personally, I think that unilateral disengagement in Gaza alone should be taken, even if we cannot annex Jewish settlements in the West Bank," he said.
Such statements of support have pleased Mr. Sharon, but a number of Israeli observers agree that a lot still hinges on the outcome of the White House talks.
When the two leaders finish their discussions, they are meant to have exchanged letters, setting out the details of Mr. Sharon's plan and what Mr. Bush can be expected to provide in terms of support.
The contents of Mr. Bush's letter have been the subject of strong speculation in Israel, suggesting that Mr. Sharon had high expectations ahead of the summit in Washington.
Some observers in Israel consider the document the biggest event since the so-called "Balfour Declaration," when the then British foreign secretary, Arthur James Balfour, offered Zionists a state in their biblical homeland in 1917.
What Mr. Sharon is demanding is that Mr. Bush follow in this tradition by promising that Israel can include within its boundaries the large settlement blocs in the West Bank, and reject the Palestinians' long-standing claim for their refugees to return to areas that are now part of the Jewish state.
The Palestinian foreign minister, Nabil Shaath, says such a move is entirely unacceptable to the Palestinian leadership.
He says, even if Israel leaves Gaza, the Palestinians will not give up their long-standing demand for statehood, including the right of return for refugees.
"Nothing that will pre-empt permanent settlement [of the Israeli-Palestinian conflict], neither on borders, nor refugees, nor anything, this will not be accepted, unless it is part of the [international] road map [peace plan], and it should be coordinated with the Palestinians," he said.
Faced with such strong opposition, some observers believe, Mr. Sharon is aiming too high, at a time when he is running into political troubles, and Mr. Bush is preoccupied with problems elsewhere.
In Israel, Mr. Sharon is facing the possibility of a criminal indictment, following a police investigation into bribery allegations.
And Mr. Bush's Middle East foreign policy is under scrutiny because of the recent uprising against the U.S.-led coalition in Iraq.
As a result, the depth of Mr. Bush's commitment to Israel is facing a major test on Wednesday. Mr. Sharon is betting that Mr. Bush will back him, more than even some in his own party expect.
The Israeli leader believes that too much is at stake for a defeat of his plan at the Likud referendum, which could see Mr. Sharon lose his grip on power, and introduce a new element of instability into the region.
Mr. Sharon, perhaps more than any other leader in Israel's history, has decided to place a key strategy and his own political survival in the hands of the president of the United States.