The latest phone call came from a journalist in Denmark. Why, he asked, has Israeli settlement in the West Bank continued despite peace negotiations with the Palestinians?

As a historian of settlements, I'm used to this question. Outgoing Prime Minister Ehud Olmert insists that Israel's future depends on a two-state solution. Building new homes in settlements only makes it more difficult to withdraw. When President Bush convened the Annapolis conference last November, there was media buzz about a settlement freeze. Olmert said that every request to build from within the government required his approval. Yet in the past year, construction has increased -- despite Olmert's talk, despite Bush's supposed commitment to his 2003 "road map" plan with its freeze on settlement.

Nearly a thousand housing units are being built in Maale Adumim, according to Peace Now's Settlement Watch project. At Givat Zeev, another of the settlements ringing Jerusalem, a 750-unit project was approved this year. The government has asked for bids on building nearly 350 homes in Beitar Illit, also near Jerusalem. Meanwhile, hundreds of homes have been added at settlements deep in the West Bank, with the government's acquiescence if not approval.

All this fits a historical pattern: Diplomatic initiatives accelerate settlement building in occupied territory. When the peace effort fades away, the red-roofed houses remain as a monument.

Maale Adumim, a hive of apartment buildings on the parched slope between Jerusalem and Jericho, is the most imposing example. Secret discussions about settling at the site began within the Israeli government in August 1974. At just that time, Secretary of State Henry Kissinger was mediating between Israel and Jordan on an interim peace agreement. Israeli Foreign Minister Yigal Allon proposed that Israel would withdraw from Jericho as a first step toward realizing his larger plan: Israel would also give up major Palestinian towns deeper in the West Bank.

But Allon wanted to keep much of the West Bank under Israeli rule -- including a ring of land surrounding Jerusalem and separating it from Jericho. By the fall of 1974, the Israeli-Jordanian contacts had failed. But Allon's political ally, settlement czar Yisrael Galili, pushed on with Maale Adumim. Building is easier than negotiating, and it is harder to stop.

The government's method of acquiring land for the settlement was audacious -- and, until now, well hidden. After a tenacious freedom-of-information legal battle, Israeli human rights activist Dror Etkes of the organization Yesh Din recently received data from the Israeli army's Civil Administration on West Bank land expropriations. In April 1975, Israel expropriated 11 square miles east of Jerusalem "for public use." In 1977, another square mile was taken.

On his laptop, Etkes showed me an aerial photo of the settlement today, superimposed on a map of the expropriation. Most of the built-up area of Maale Adumim lies inside the land that was confiscated.

This is a prima facie violation of international law. Under the 1907 Hague Convention, an occupying power may expropriate land only for the public use of the occupied population. Taking private West Bank land for Israeli use is therefore barred.

That's just one example of the historical pattern. In 1970, Israel and Egypt ended their "War of Attrition" under a cease-fire proposed by Secretary of State William Rogers. The next stage of the Rogers initiative was supposed to be peace talks. Fearing pressure to withdraw, the Israeli cabinet approved the first settlement in the Gaza Strip to stake Israel's claim to the territory. Diplomacy stalled, but settlement continued in Gaza.

The pattern repeated itself in 1998, when President Bill Clinton convened the Wye River summit to revive the Oslo process. The summit ended with an Israeli commitment to resume West Bank withdrawals and a Palestinian pledge to suppress terrorism. Neither promise was kept. But Ariel Sharon, then foreign minister, returned home and publicly advised settlers to "grab more hills, expand the territory. Everything that's grabbed will be in our hands. Everything we don't grab will be in their hands." That spurred establishment of the tiny settlements known as outposts that dot the West Bank.

Since Annapolis, hard-line settlers have continued building, hoping to block any pullback. The government, meanwhile, is building in the so-called settlement blocs -- settlements that it insists Israel must keep under any agreement. As in the past, it is writing its negotiating position in concrete on the hills. That includes more construction on the expropriated land at Maale Adumim.

As shortsighted as Olmert has been to allow this, the same is true of Bush. The president began a negotiating process but has invested little effort in pursuing it. The administration's objections to settlement expansion have been too faint. The new buildings are a monument to Bush's failure as well as Olmert's. They will make Israeli-Palestinian peace a more difficult challenge for the next president -- assuming the next president cares about pursuing peace.