As a young member of Israel's parliament in 1978, Ehud Olmert had the opportunity to vote in favor of the historic Camp David peace accords, which returned the Sinai Peninsula to Egypt and brought Israel peace with its most powerful enemy. Olmert voted against it.

"I voted against Menachem Begin," Olmert, now Israel's finance minister, said this week. "I told him it was a historic mistake, how dangerous it would be, and so on and so on. Now I am sorry he is not alive for me to be able to publicly recognize his wisdom and my mistake. He was right and I was wrong. Thank God we pulled out of the Sinai."

In two days, the Israeli military will begin the first evacuation of Jewish settlements since the Sinai pullout, abandoning 21 settlements in the Gaza Strip and the network of military installations that protected them for nearly four decades. This time, Israel will not receive anything in return for the land it is leaving. Olmert has been one of the plan's most vocal supporters.

The unilateral decision to leave Gaza, pushed for more than a year by Prime Minister Ariel Sharon at great political expense, has left Israeli society at odds over the future character and shape of the Jewish state.

After Israel captured the West Bank and Gaza in the 1967 Middle East war, Israeli Jews moved to settle the newly occupied territories. From about 5,000 in the late 1960s, the number of Jewish settlers in the West Bank and Gaza has grown to about 258,000 today, not including those who live in East Jerusalem neighborhoods that Israel annexed following the war.

But over the past year or so, the dream of settling the territories has collided with Israel's demographic challenge -- how to survive as a democratic Jewish homeland -- convincing most Israelis that the state must give up land to protect its Jewish majority. At the same time, the violent Palestinian uprising that began in September 2000 was claiming thousands of Israeli and Palestinian lives.

Sharon, an architect of the settler movement, has long supported the notion of a Greater Israel stretching from the Jordan River to the Mediterranean Sea. But he has scaled back those territorial ambitions. Even though disengagement amounts to the first time outside the framework of peace negotiations that Israel will withdraw from what many Jews consider part of the Land of Israel described in the Bible, Sharon has cast it as a step toward creating a state that has more defensible boundaries with fewer Arabs inside them.

A recent poll conducted by Tel Aviv University showed that 57 percent of Israelis support the plan, a majority that has remained relatively constant throughout the tumultuous debate.

The same poll showed that 36 percent of the population opposes Sharon's plan to evacuate Gaza and four small West Bank settlements. Many of the opponents are from a younger generation, energized by a summer of protest, who have become the foot soldiers of a more politically assertive religious minority.

Whether the evacuation unfolds smoothly will probably determine Israel's immediate course on matters of peace with the Palestinians, the role of settlers in Israeli society and the outcome of general elections that must be held by November 2006.

"If this is done properly, there are a lot of options open to us," said Eyval Giladi, Sharon's director of strategic planning. "If we fail, there will be a lot fewer."

A Demographic Race

For nearly 40 years, Gaza has proved to be a difficult place to defend and an even harder one to leave. The government initially encouraged Israelis to move into its dunes for strategic reasons -- to create a bulwark against an Egyptian invasion and divide the Palestinian population. The settlers, a mix of religious and economically motivated Israelis, developed farms and greenhouses, staffed by cheap Palestinian labor.

In 1994, under the terms of the Oslo accords, Israel handed the Palestinians political control over roughly 80 percent of Gaza's territory. But the Israeli army and the Jewish settlements remained. Today, about 8,500 Jewish settlers live among 1.3 million Palestinians in Gaza, an imbalance that has proved costly in lives and money to sustain.

Under international pressure to make progress toward peace, Sharon proposed the unilateral withdrawal from Gaza in part to avoid negotiating with Palestinian leader Yasser Arafat. After Arafat died in November, the election of Mahmoud Abbas to succeed him as president of the Palestinian Authority brought a cease-fire agreement with Israel.

But coordination remains tenuous, giving radical Palestinian groups such as the Islamic Resistance Movement, known as Hamas, an opening to claim that the Israeli withdrawal is a result of their rocket attacks and suicide bombings. Hamas is sponsoring a contest for the best mural depicting the Israeli evacuation as a victory for the group.

According to population projections, the number of Arabs living between the Jordan River and the Mediterranean Sea will surpass the number of Jewish residents, who now total roughly 5.2 million, by the end of the decade.

Israeli political leaders worry that, unless a two-state solution to the conflict can be reached by that point, the 3.5 million Arabs living under Israeli military law in the West Bank and Gaza will give up the goal of having their own nation. Instead, they could demand the right to vote inside Israel, where 1.3 million Arab citizens already live, forcing Israelis to choose between the state's Jewish character and democracy.

"Among the Israelis, there has been a shift in thinking," said Ali Jarbawi, a Palestinian professor at Beir Zeit University near Ramallah. "Now, instead of land for peace, it is land for time."

The key players in the demographic race could be seen here last week at the Western Wall in Jerusalem's Old City, where more than 70,000 people gathered to protest disengagement by chanting prayers of lamentation and forgiveness. Young couples flooded into the plaza, pushing scores of baby strollers. One religious settler held a baby in one arm and a prayer book in the other, his M-4 rifle slung over his shoulder.

"The prime minister has changed and the situation has changed," said Shimon Peres, the deputy prime minister, who has been Sharon's friend since the two were active in Israel's pre-state security organizations. "Zionism was built on geography, but it lives on demography."

As leader of the Labor Party, Peres joined Sharon's Likud-led government largely to protect the disengagement plan. But the unusual political alliance, built on generational rather than partisan lines, may shatter once the election season begins after the evacuation.

"What to do next on the West Bank has been a silent discussion until now," Peres said. "Once we are out of Gaza, it will become an open debate, maybe even the central debate in the next election."

Building a Coalition

Amiel Ungar lives in the hilltop settlement of Tekoa in the southern West Bank, in a stucco home where he moved 26 years ago from New York. He has raised five sons there on the barren edge of the Judean Desert, the rocky heart of what religious Zionists believe is the Promised Land.

Ungar, a lecturer at Ariel College in the West Bank, said religious settlers like himself have played an important role in mainstream Israeli life for years. They do obligatory military service, unlike members of the ultra-Orthodox community, and are prominent in the army's professional officers corps.

"We simply won't be lectured to by people who preach democracy, but this European-style democracy that believes it knows better than the people," said Ungar, 57.

Israel's religious Zionist movement holds a range of opinions on the terms of any future peace agreement with the Palestinians. Ungar said the movement's mainstream consensus is that the Palestinians should accept the Israeli presence in the territories or else move to Jordan or Egypt. Disengagement, he said, rewards Palestinian militancy.

Many Israelis believe the settlement movement is an obstacle to peace, an impression reinforced during recent months of resistance to the evacuation plan. Many secular Israelis, especially those on its coastal plain, argue that the government created the problem by pampering the settlers for years.

"They have long been the spoiled child in the family," said Kobi Niv, a screenwriter and teacher at Tel Aviv University. "Now, suddenly, the father -- and he's truly their father -- has said, 'Enough.' "

In the coming months, Ungar said, the religious Zionist movement will begin building a new electoral coalition. It will reach out to disaffected Likud members, residents of Israel's poorest cities, Russian immigrants and secular war veterans who still believe in a Greater Israel.

"The entire generation, the boys and girls of summer 2005, are going to demand a change," Ungar said. "The government has made a decision. A future government may be able to rectify that decision."

The New Generation

Many of those boys and girls have gathered in Neve Dekalim, the largest settlement in Gaza. They have turned the community square into a kind of joyless festival, a party counting down the end of the community.

The Palestinian "solution for peace is that we all should die," said Avivit Partush, 24, who arrived from her home near Tel Aviv to join the disengagement opponents. "There are many states where they can live. We are surrounded by countries that are their countries."

Partush and a few friends, all of them religious, are running a nonprofit snack bar from a derelict van. They have received donations to support the holdouts and sell their sandwiches for less than 50 cents each. Hagai Swisa, 25, left the Israeli army after five years because he would not participate in the disengagement operation. Now, a week later, he is helping feed the demonstrators after sneaking through the military cordon around Gaza to get inside.

"We're willing to take one step more than our parents," Swisa said.

Just down the road, along a strip of beach behind a tall metal fence, are the hard-core holdouts of Shiryat Hayam. Hundreds of settlers have gathered there in recent weeks. The army predicts that it might be one of the few places where the evacuation turns violent. It is easy to see why.

A group of children, some not even teenagers, stand at the gate into the camp. They wave some cars through, tell others to turn around, even though the Israeli soldier has given permission to pass.

"You can run them over for all I care," a harried Israeli soldier said one recent afternoon.

"The soldier means nothing to us," one angry teenager inside the camp said. "He has no authority here."

A Jewish resident of the Nissanit settlement in Gaza walks through her empty house. The walls are painted with slogans against the disengagement plan.