US President George W Bush has backed Israeli Prime Minister Ariel Sharon's "disengagement plan" with some significant shifts in Washington's policy in Israel's favour, although he has tried to allay some Palestinian fears. BBC News Online's Martin Asser looks at the key issues.
What has President Bush agreed to?
Mr Bush has welcomed the essence of the Sharon plan which intends to pull out of the Gaza Strip and parts of the West Bank.
Israel will dismantle all its settlements in Gaza and some in the West Bank and pull its military back throughout the occupied territories.
Mr Bush also went further than any previous US president in recognising Israel's settlements in the West Bank and countering the claim that millions of Palestinian refugees have the right of return to their homes in what is now Israel.
The president justified this departure from long-established policy positions based on UN resolutions by saying that Israeli and Palestinian negotiators have reached the same conclusions in past peace talks.
How exactly has US policy shifted?
Because of "new realties on the ground, including already existing major Israeli populations centres", the president said a full withdrawal from land captured by Israeli in 1967 was now "unrealistic".
Past US administrations have said Israeli settlement activity which led to establishing these population centres - illegal under international law - was incompatible with peacemaking.
FUTURE SETTLEMENT BLOCS
Settlement block populations:
Maale Adumim - 30,000
Ariel - 18,000
Kiryat Arba - 4,000
Hebron enclave - 500
Givat Zeev - 10,000
Gush Etzion - 30,000
As for the Palestinian refugees, Mr Bush said a "just, fair and realistic" way to end their five decades in exile was for them to settle in a future Palestinian state, not in Israel.
These positions pre-empt the international peace plan known as the roadmap, which stipulates negotiations to decide all the so-called final status issues - refugees and settlements, as well as permanent borders and the status of Jerusalem.
There was another subtle departure from the roadmap text - Mr Bush said Israeli commitments included "progress towards a freeze on settlement activity".
The roadmap text actually states Israel must freeze "all settlement activity (including natural growth of settlements)".
Was there anything for the Palestinians?
Palestinians are reeling from Mr Bush's denials of their strongly-held negotiating positions - complete Israeli withdrawal from the West Bank and Gaza, the illegality of settlements and right of return of refugees under UN resolution 194.
Their leaders are indicating that the US can no longer be held to be an honest broker.
They can only console themselves with the fact that Mr Bush insisted the barrier Israel is building in the West Bank should be a temporary security measure, not the basis of a permanent political boundary.
He also spoke at length in support of Palestinian aspirations to gain statehood, calling for "a viable, contiguous, sovereign and independent" state.
But he did not address Mr Sharon's recent assertion that "in the unilateral plan, there is no Palestinian state".
All this will do little to mitigate the fact that President Bush has endorsed a plan which if implemented effectively settles all of Israel's issues, and hardly any of the Palestinians', without the need for further negotiations.
Where does it leave Mr Sharon?
Surely even the Israeli leader's most optimistic fans cannot have hoped for a better result from his trip to Washington.
But the disengagement plan - whose success could yet determine the survival of Mr Sharon's government - has still got to clear some hurdles before it is implemented.
Firstly, on 2 May, the 200,000-strong rank and file of the ruling Likud party get to vote on it, with some leading party members having pledged to oppose the plan.
If Mr Sharon wins, the plan will be presented to the cabinet and then parliament.
He will probably have to rebuild the government in the face of resignations from entrenched pro-settlement coalition members.
Shimon Peres, the Israeli Labour party leader, has already said he will back the disengagement plan in parliament, and may join a national unity government should Mr Sharon need to form one.
But Mr Bush's enthusiastic endorsement will boost the plan's chances considerably.
This is something Mr Sharon badly needs after facing increased discontent about his performance and the possibility of being indicted over a bribery scandal.
What happens if the disengagement plan is implemented?
The hope for Israelis is that the problem of suicide bombing will diminish considerably, without their having to wait for a Palestinian leadership to emerge with whom the Israeli government can resolve the conflict.
Hundreds of thousands of Palestinians, meanwhile, will escape from a crushing military occupation. Although the Israeli army will maintain its capability to invade from new positions encircling the territory they withdraw from.
The danger is that the new arrangement will become crystallised without any further progress towards further Israeli-Palestinian peacemaking, let alone moves to end the wider Arab-Israeli conflict.
Gaza would become a single Palestinian entity, but without controlling its own land or sea borders or airspace.
Palestinians in the West Bank might be enclosed in several cantons divided by the six settlement blocs that Mr Sharon has said he will hold onto.
Hebron might remain a serious flashpoint, with three Jewish settlements in the heart of the southern West Bank's largest Palestinian town.
The status of Jerusalem would be almost impossible for Palestinians to put back on the negotiating agenda as the city would be separated from the West Bank on three sides by the Givat Zeev, Gush Etzion and Maale Adumim settlements.
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