The expression "chaos in the Middle East" is an overworked cliché, but it accurately describes the impact that Ariel Sharon's stroke will have on Israeli politics and the future of the region in general.

There is a consensus growing in Israel that his condition is so grave that he will not be able to return to politics, assuming he even survives the stroke that he has suffered. The Sharon era is over.

Mr Sharon has dominated the Israeli political scene since he came to power five years ago and his removal will cause a huge power vacuum and a political implosion.

His recently formed party Kadima had until yesterday been expected to win a landslide in the March 28 elections. Now the race is wide open.

Ehud Olmert, the Deputy Prime Minister who defected with Mr Sharon from the Likud Party last year, has been appointed caretaker prime minister, a post he can occupy for 100 days. He is a political lightweight compared to Mr Sharon.

To win the party's support and make a convincing showing in the elections he will have to transform himself in the eyes of the Israeli public.

First he has to win the party's leadership race. He will be up against Tzipi Livni, the Justice Minister, General Shaul Mofaz, the Defence Minister, and possibly Shimon Peres, the former Labour Party leader, who joined Kadima late last year.

Then he will have to turn a one-man party, created by Mr Sharon, into a political movement that can take on the established parties like Likud and Labour. He has to achieve this all in two months, an impossible task.

Mr Sharon's removal is a gift for Benjamin Netanyahu, the Likud leader, whose party faced a humiliating defeat in the March 28 polls. As the most experienced of the Israeli leaders left in the field he can expect to see his fortunes improve, particularly if the Israeli public grows concerned about the violence and chaos among the Palestinians.

President Bush, Western leaders and some moderate Arab figures had been counting on Mr Sharon to win the election and move to the next stage of what he termed "painful compromises". It was widely expected that following on from last summer's withdrawal of Israeli forces and Jewish settlements from the Gaza Strip, he planned to unveil a similar partial pullout from some areas of the West Bank.

Mr Sharon would almost certainly have aimed to complete his controversial separation wall as well. While this would have fallen far short of Palestinian demands and could have reinforced Israel's claims to some areas of the occupied West Bank, it would nonetheless would have moved the process forward.

Progress on the Israeli-Palestinian track is regarded as crucial for American efforts to prove to the Arabs and the Islamic world that it is serious about bringing peace to the Middle East and promoting democracy. Without a strong, pragmatic leader in Israel that task will be very difficult, if not impossible.

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