Donald Macintyre: Era of uncertainty to begin for Israel and Middle East

Ariel Sharon's capacity to make Israeli politics unpredictable was proved two months ago when he became perhaps the first elected head of government to form his own breakaway party.

But nothing could be more unpredictable than what will follow if the career of the man who has dominated Israel for five long years is now over. His absence will throw up even more imponderables than his presence ever did. And nowhere more so than on the question of a lasting peace with the Palestinians. Before Mr Sharon's second stroke, conventional wisdom had already began to form about the Israeli general election on 28 March. It was that by sheer force of his personality - and with very little yet clear about his future programme - his new party, Kadima, would become the single biggest in the Knesset, making him virtually unchallengeable as a third-term Prime Minister.

Labour, under Amir Peretz, a new leader committed to substantive negotiations with the Palestinians, would be a runner up and - perhaps - a coalition partner. And the man who had become in some ways Mr Sharon's bitterest rival, Benjamin Netanyahu, would come a respectable third, perhaps forming a vigorous right-wing opposition. Without Mr Sharon, those assumptions are all shattered. Kadima has some substantive figures; Ehud Olmert, ex-officio the current Prime Minister, and Justice Minister Tzipi Livni are two of them. But it will have an uphill struggle to convince the electorate that Kadima's appeal was as anything more than as a personal vehicle for Ariel Sharon - and that without the old man it will be an empty shell.

This in turn indicates that come 28 March the electorate may paradoxically face a clearer choice than it has almost ever done before; between an energetic Labour leader committed to reversing inequalities within Israeli society and to a just peace with the Palestinians, and to a Likud one whose opposition to Gaza disengagement suggests he has never given up on the dream of a greater Israel.

Mr Netanyahu has the advantage, in a country which richly rewards experience over youth, of having been Prime Minister before; Mr Peretz that of going with what looks like the grain of mainstream Israeli opinion in seeing the destructiveness of the occupation for Israelis as well as Palestinians. And Mr Peretz can point out that it was Mr Sharon, and not Mr Netanyahu, who took the bold step of dismantling settlements.

This is a crisis, perhaps an overdue and necessary one, for Israeli public opinion. The polls suggested that the electorate was happy to leave Ariel Sharon extraordinary leeway in deciding the big questions for it. It was preparing to vote for him while knowing extraordinarily little about what he was actually preparing as his next step after Gaza disengagement. Arik, they thought, has Israel's best interests at heart; he would take care of them. Now they have to decide for themselves.

If Mr Sharon does not sufficiently recover to fight the elections, Kadima will certainly claim his mantle and try to maintain the supremacy he bequeathed it. But the voters are unlikely to be as indulgent to its new leaders; what it really intends to do about the Palestinians will have to be stated more clearly. It may just be that a clear and historic choice between negotiation and conflict is finally at hand. It may well not happen, of course; but it is just possible that the Sharon legacy will be to give the most interesting Labour leader since Yitzhak Rabin a chance to lead his country.