In the tan hills a few miles east of Jerusalem, construction cranes dangle over a string of red-roofed neighborhoods that make up the largest Jewish settlement in the West Bank. It is here that Prime Minister Ariel Sharon is reengaging with his electoral base following Israel's efficient but divisive exit from the Gaza Strip.

Enjoying a moment of international sympathy, Sharon's government is moving swiftly to capitalize on its unilateral withdrawal and ongoing demolition of 25 Jewish settlements. The government's efforts are focused largely in the West Bank, land of far more religious and strategic importance to Israel than the remote slice of coastline it has left behind.

A little more than 31,000 Israelis live in Maale Adumim, a suburban settlement built on land captured by Israel in the 1967 Middle East war. Israeli officials say it will grow to more than 50,000 people and eventually touch the edge of East Jerusalem, even though the U.S. government and Palestinian leaders have said that such growth would severely complicate efforts to establish a viable Palestinian state.

Last week, as the world watched settlers being hauled from their homes in Gaza, government officials ordered the confiscation of 400 acres of West Bank land for a barrier that will separate Maale Adumim from Palestinian-populated territory. Just east of the main settlement, where construction plans had been frozen because of U.S. opposition, Israel will soon break ground on a new police headquarters serving the entire West Bank.

"I hope Israel is not going to use the fact it has done something right in withdrawing from Gaza in order to do a lot wrong regarding settlement activities, the wall and other matters," said Saeb Erekat, the chief Palestinian negotiator. "I hope they will use this to stay the course and to return to negotiations."

The fate of these hilltops in the coming months will likely determine whether Israel's withdrawal from Gaza refreshes the peace process or generates new friction.

Palestinian officials say the move to begin construction in new sections of Maale Adumim risks squandering the goodwill Israel generated by uprooting settlements for the first time on land designated to be part of a future Palestinian state.

Gaza has become the proving ground for that nascent state, and building a viable economy and political culture there will depend in large part on the nature of its connection to the more prosperous West Bank.

But Palestinian officials say Israel's plans around Jerusalem, a city both sides claim as their capital, will make nation-building far more difficult.

Sharon, seeking to shore up his tattered political base before next year's elections, is acting on assurances he received last year from President Bush after presenting him with his plan to evacuate all 21 Jewish settlements in Gaza and four in the West Bank.

The April 2004 letter from Bush has become a cornerstone of Israeli efforts to seek additional U.S. aid, propose borders beyond the demarcation between Israel and the territories, and build within West Bank settlement blocs such as Maale Adumim.

"In this case, the Palestinians are not giving the quid pro quo" for the Gaza pullout, said Dore Gold, an adviser to Sharon. "This time, the quid pro quo comes from the United States."

The father of the settlement movement, Sharon has received international praise for removing communities he once pushed to build, but he faces the difficult task of mending fences at home. With elections likely next spring, Sharon's quick return to high-profile settlement construction around Jerusalem was a widely expected attempt to win back his alienated followers.

"I know everyone saw the pictures coming out of Israel as we took this courageous step," said Gideon Meir, a senior Foreign Ministry official. "I think we need some time now to be among ourselves. What will happen now with the Sharon government needs international backing and help."

Israeli officials say the goal now is to return to the U.S.-backed peace process known as the "road map." Following the Gaza evacuation, Israeli officials and the Bush administration have placed the onus on the Palestinians, saying they must now show they can govern impoverished, isolated Gaza and control its armed groups.

To do so, Mahmoud Abbas, the Palestinian Authority president, will need help of his own to build an economy capable of sustaining Gaza's 1.3 million residents and to improve the position of his mainstream Fatah political movement before Jan. 25 parliamentary elections.

"We're going to be out of there really soon, and so here comes the challenge" for Abbas, said Eyval Giladi, Sharon's director of strategic planning. Giladi, who was Sharon's point man on disengagement, praised Abbas for ensuring that the evacuation took place largely free of Palestinian fire. He said Israel would do what it could to support him.

"The incentive is there, the conditions are there, the international support is there," Giladi said. "But someone must take the lead and manage the situation."

Abbas's greatest political challenge comes from the Islamic Resistance Movement, or Hamas, which has portrayed Israel's withdrawal from Gaza as a victory for its armed wing. But Abbas has decided not to disarm Hamas or Islamic Jihad, a smaller radical group.

Michael Tarazi, a legal adviser to the Palestinian Authority, said a previous effort to disarm Hamas after the 1993 Oslo peace accords was "wildly popular" among many Palestinians who believed it was an essential part of a working peace process.

But Tarazi said Hamas's armed strategy has grown in popularity during the uprising that began in 2000, while moderate Palestinians who favor negotiations have insufficient support to move against radical groups.

"No one believes the process is working anymore," Tarazi said. "What do we get out of disarming Hamas? The right to negotiate?"

Using Bush's April 2004 letter to Sharon as a guide, Israeli officials are seeking a $2 billion aid package from the United States to help defray the costs of the evacuation and develop the Israeli regions of Negev and Galilee.

More important for peace prospects, however, is the letter's acknowledgment that Israel would be allowed to keep "existing major Israeli population centers" in the West Bank in any final agreement with the Palestinians. Israeli officials cite the letter to justify construction in Maale Adumim, where plans call for 3,500 houses and apartments to be built in the next phase. The new housing units will accommodate 15,000 new residents, nearly twice the number of settlers cleared from Gaza.

According to Israel's Interior Ministry, the population of Jewish settlements in the West Bank has grown by 11,700 over the past year, and a report issued last week by the Palestine Liberation Organization's Negotiations Affairs Department asserted that the new construction will "mean the end of the two-state solution."

"Israel's strategy continues unabated, and that strategy is simple: to take as much Palestinian land as possible with as few Palestinians as possible," Tarazi said. "Once you understand that, you understand everything that is happening on the ground."

Gold, a former ambassador to the United Nations who heads the Jerusalem Center for Public Affairs, worries that the attention being paid to the evacuation of Jewish settlements is overshadowing Israel's security requirements. Bush's letter acknowledged Israel's right to "secure, defensible borders," and Gold's policy institute recently published a report suggesting such boundaries might reach as far east as the Jordan Valley given the uncertainty in Iraq, Iran and Jordan.

"Israel withdrew lock, stock and barrel from Gaza, and that withdrawal cannot be replicated in the West Bank," Gold said. "I do not think the viability of a Palestinian state depends on its size. Just look at Bahrain and Singapore."

A Bedouin shepherd walks with his sheep past the Israeli settlement of Maale Adumim, the West Bank's largest settlement, not far from Jerusalem.Palestinian workers pour concrete for a new building in Maale Adumim.A view of a strategic hilltop in the West Bank where Israel plans to build a police station on land linking the Maale Adumim settlement to Jerusalem.