The obsessive asking of the question, "Who is Ariel Sharon?" is justified. Not since David Ben-Gurion has there been an Israeli prime minister who held so much political power. Not since David Ben-Gurion has there been an Israeli prime minister who faced such fateful decisions. Not since David Ben-Gurion has there been only one person upon whom the fate of the Jewish state depends the way the fate of the Jewish state now depends on the lone figure of Ariel Sharon.

There's another good reason for the worldwide obsession with the prime minister's personality: Never has Israel had a leader like Sharon, whose very personality contains such a profound ideological contradiction. Never has there been a leader who belongs so emotionally and ideologically to both the right-wing camp and the left-wing camp, but in effect to neither. And never has there been a prime minister here who has surrounded himself with such a thick fog regarding his essential worldview, a prime minister who, on the eve of a dramatic historic decision, makes it so difficult to see where he truly is heading: Is he Golda or Rabin? Is he Shamir or de Gaulle?

To remove any doubts, he's not de Gaulle, nor will he become de Gaulle. He would never even consider being de Gaulle. Ariel Sharon will not go back to the 1967 borders, nor even approach the 1967 borders. He won't dismantle the settlement enterprise, nor will he bring home 200,000 Israeli pied noirs.

Nor will Ariel Sharon end the Israeli-Palestinian conflict. It's highly doubtful whether he'll even sign a peace treaty. As a man of historical continuity and organic development, Sharon won't turn his back on his own biography. He will not uproot all that he planted. He will try to move toward the maximum possible conciliation without rejecting his past and without permanently divorcing all that came from him.

He is also not Shamir. Those who tend to minimize the importance of the new terms of discourse Sharon has been using since Passover eve, or dismiss the value of the historic decision he pushed through the government this week - are wrong and misleading. The prime minister did indeed cross the Rubicon; he means to do something.

Therefore, the Ariel Sharon of 2003 is not the Yitzhak Shamir of 1991. He is not juggling words just to gain time. He is not staging hollow political revues just to satisfy the man in the White House. Sharon indeed thinks that the occupation - yes, the occupation - is leading nowhere. Sharon indeed has reached the conclusion that it is impossible to continue ruling Nablus and Jenin. So, ultimately he will retreat. He will do so in the coming two years. If his health does not betray him and if his political base does not collapse beneath him, Sharon indeed will divide the Land of Israel in the coming two years.

So where should he be placed on the map? Where does he fit on the left-right axis? The answer is clear: Sharon is now belatedly taking up his place in the mainstream of the historic Labor movement. Left of Golda Meir. Right of Abba Eban and Pinchas Sapir. Very close to where Yigal Allon once stood.

And truthfully, Sharon after the Al-Aqsa Intifada is even closer to Allon after the Six-Day War: a determined hawk and man of the Greater Land of Israel who discovers the demographic and political reality. A tough security-minded man, an experienced military commander, who understands that if Israel wants to live, it must give up the densely populated areas of Judea, Samaria and Gaza.

So, where is Sharon heading? To a beefed-up Allon plan. In conversations with close associates, he has spoken more than once about a Palestinian state in two-thirds of the West Bank (in the west), with a tenth annexed to Israel, and a fifth (in the east) remaining in Israel's hands for a generation, for security purposes.

Unrealistic? It could be. But even a plan like that requires uprooting dozens of settlements. And Sharon can definitely claim that as long as the Palestinians are demanding the right of return, Israel is allowed to demand the Allon Plan. As long as the Palestinians refuse to accept that Israel's case is the same as France's, Israel has the right to claim the northern beaches of Algeria.

The problem is that Sharon's Allon vision does not suit the road map. The ambitious international plan leads to an unequivocally Gaullist solution: Israel's complete departure from the territories even before the Palestinians agree to give up the right of return. Therefore, Sharon's vision and the road map are on a dangerous collision course right now.

Ariel Sharon did a brave thing this week. He proved he has the potential for historical greatness. But now he doesn't have a minute to waste. In a very short time, he must translate his hidden worldview to an open Israeli plan that will finally define Israel's position, its expectations of the relationship between it and Palestine and the border between them. He must place the idea of a Jewish, democratic state at the center of the road map. If Sharon doesn't do it, if he doesn't take the political initiative into his own hands, he could yet find himself steamrolled by the iron wheels of the process that he himself sent on its way this week.