Israeli Prime Minister Ariel Sharon is facing the toughest challenge of his long and storied military and political career: the forced evacuation of the remaining Jewish settlers from the Gaza Strip and a few enclaves in the northern West Bank.

After two years of decision-making and preparations, Israel's military and police forces will be ordered to direct — or drag — the reluctant settlers to waiting buses, en route to their new life outside Gaza.

For Israel's right wing, Sharon's "disengagement" amounts to heresy, a destruction of Zionism and a security folly. For the left, it offers a chance to consolidate Israel's democracy and its Jewish majority, albeit on a smaller slice of Middle East territory. The less-ideological centrists will be happy to get rid of the Gaza nightmare, even if "the day after" is blurred in uncertainty.

It is no small irony that it is Sharon, of all people, who carries out the task of leaving Gaza. My generation of Israelis grew to treat him as a reckless user of force, who launched an adventurous, but morally and politically wrong, invasion of Lebanon in 1982. In his many Cabinet roles, he was always the patron of the settlement enterprise, using the settlers' religious fervor to realize his concept of topographic superiority over the Palestinians.

His about-face in Gaza has left his erstwhile allies devastated, vowing to destroy him, while winning him the admiration of his liberal former critics. Foreign leaders such as Egypt's Hosni Mubarak and France's Jacques Chirac, who had castigated Sharon for his brutal tactics in breaking the four-year Palestinian intifada, are now praising his "courage."

No previous Israeli government, even the most dovish one, has ever dared to remove any settlement in the West Bank or Gaza, parts of the pre-1948-mandate Palestine. Under the Oslo peace deal with Yasser Arafat, all settlements were to remain in place until "final status" arrived, meaning until all the other thorny issues were resolved.

But Oslo failed, and Sharon, who had fiercely opposed the 1993 agreement, is now taking it from there, and further than any of his predecessors.

Why Sharon? There are two explanations: the nature of Sharon's political philosophy and his public persona.

At the heart of Sharon's strategy lies a conviction in unilateralism. It fits his psyche and his deep distrust of Arabs. "My mother told me, 'Never believe them,' " he said recently.

Upon taking office as prime minister, Sharon feared an internationally imposed resolution of the Palestinian-Israeli conflict, one that would require Israeli withdrawal from east Jerusalem and virtually all of the West Bank. To pre-empt it, he avoided negotiations with Arafat, whom he viewed as a hopeless terrorist. To Sharon, peace talks equaled a "corral" leading Israel to the slaughterhouse.

When Mahmoud Abbas took the reins of the Palestinian Authority following Arafat's death last November, Sharon praised his moderation but dismissed him as a peace partner. For Sharon, acting unilaterally leaves the initiative in Israel's hands and avoids the corral. He had also learned the lesson of his hapless predecessor, Ehud Barak, who withdrew Israeli forces from Lebanon but failed miserably at negotiations with Syria and Arafat. As long as Sharon refused to negotiate, he could avoid a similar failure.

So after an initial hesitation, Sharon launched the project of his lifetime, drawing Israel's border with the Palestinians in two segments — the security barrier in the West Bank (which leaves about 10 percent of the West Bank's land on its western, Israeli side) and the pre-1967 "green line" in Gaza.

Although Sharon still denies the territorial implication of the barrier route — it is not a border but a means of ensuring Israel safety, he says — it is clear to most Israelis (and everyone else) that what looks and behaves like a border will eventually become one, even though this implies the future evacuation of more Israeli settlements on its "other" side.

But Sharon's unilateralism is only part of the explanation behind disengagement. His leadership image is no less important. Sharon is a unique combination among Israeli leaders: He possesses an unrivaled military record and unmatched political shrewdness, based upon a sharp, instinctive knowledge of human desires and weaknesses.

His predecessors since Oslo had one quality or the other, but not both. Yitzhak Rabin and Barak were glorious generals but got lost in party politics. Shimon Peres is Israel's — and perhaps the entire world's — eldest politician, but he has never worn a uniform. Benjamin Netanyahu lacks the warrior credentials and proved too inexperienced in politics while in power. Only Sharon has the long history of striking hard against Israel's Arab adversaries and the unmatched ability to manipulate his fellow politicians.

These skills were destined to bring him finally to the threshold of the Gaza withdrawal, past endless political hurdles. And they have also brought Israel to a threshold as well, perhaps the most important in recent history. We'll soon have a better idea if Sharon's destiny includes making it successfully to the other side.

Aluf Benn is the diplomatic editor of the Israeli newspaper Haaretz. This commentary was written for The Los Angeles Times.