Cost overruns, court rulings and a decline in violence have led Israel to slow construction of a barrier through and around the occupied West Bank, and many analysts predict the project, which is a deep source of contention between Israelis and Palestinians, will not be completed.

The last substantial work on the barrier, a network of fences and concrete walls flanked by a military patrol road, was finished in 2007. The construction underway now largely involves moving parts of it off Palestinian land in response to a series of Israeli Supreme Court rulings that found that the barrier had in some cases isolated families and sealed off villages from farmland to a degree that security concerns did not warrant.

A portion of the barrier in the sparsely populated southern West Bank remains unfinished, and the Israeli Defense Ministry said in a recent memo that "for budgetary and other considerations" it did not plan to complete the barrier around Maale Adumim, a major Jewish settlement east of Jerusalem.

That will leave as much as 40 percent of the barrier's 420-mile planned route unfinished. Even with the substantial gaps, Israeli military officials and politicians credit the barrier -- one of Israel's more controversial undertakings -- with a decline in suicide and other bombings originating from the West Bank. Palestinians refer to the barrier as the "apartheid wall," saying that it is an effort to fence them off and that it effectively places as much as 10 percent of West Bank territory on the Israeli side without negotiations.

Though Israel says it can easily dismantle or move the barrier once a final border is established, U.N. officials who monitor the project say they are dubious. Even as construction on the wall itself has slowed, work on an array of related infrastructure -- checkpoints, gates, special bypass roads -- continues in what they regard as an effort to institutionalize the barrier as part of the landscape.

"We sincerely hope things will change," Christopher Gunness, a spokesman for the U.N. Relief and Works Agency, said at the debut Wednesday of a short U.N. documentary on the barrier, narrated by Pink Floyd founder Roger Waters.

The barrier was started in 2002 amid a violent Palestinian uprising, and its route was ruled illegal by the International Court of Justice five years ago. Although it accepted Israel's right to defend itself, the court criticized the degree to which the barrier, rather than following the armistice line established after Israel's 1948 war of independence, meandered through the West Bank to encompass Jewish settlements while isolating Palestinian towns, separating farmers from their land and, in some cases, stranding Palestinians on the Israeli side of the wall.

The project, designed to separate most of the West Bank from Israel, in some ways put the two sides in even closer contact, spawning weekly protests that have led to several deaths and scores of injuries, and earning "the wall" its own place in the imagery of conflict.

The Israeli military staffs a network of gates and crossings within the barrier to give farmers access to their fields. Special roads and tunnels have been carved out so that the residents of Palestinian areas isolated by the wall can travel.

In the small town of Beit Ijza, the Gharib family's home is so close to the Jewish settlement of Givon that it is penned in on all sides by the barrier. Family members said that for a while they relied on a special video link to an Israeli military outpost to get buzzed into their home through an electronic gate, but eventually the Israel Defense Forces simply decided to leave the gate open.

"It's like a prison," said Mahmoud Gharib, 43.

On the Palestinian side of the barrier, the towering concrete slabs have become a populist canvas, decorated with murals, poetry, love notes, advertising and slogans promoting Palestinian statehood.

On the Israeli side, it is seen as more than a coincidence that suicide bombings declined as the barrier snaked its way through the West Bank. The last one was 18 months ago. Although Palestinian officials argue that their changing politics and commitment to security have played a more important role, polls show that the barrier is popular in Israel. Criticism, even from dovish Israelis who favor a Palestinian state, has been over the route, rather than the barrier itself.

Retired Israeli Col. Shaul Arieli, who has written a book on the barrier, said its existence may contribute to the eventual establishment of a Palestinian state.

"Israelis have internalized the idea of separation and the division of two states," he said. "Everything outside the barrier won't be part of Israel."

In a written statement, Defense Ministry spokesman Shlomo Dror said there has been no change in Israeli policy regarding the barrier's completion.

"The security fence has been mostly constructed, although some parts have not been completed because of different considerations -- budgetary, legal and other," Dror said.

Since 2007 the political dynamics around the barrier have shifted. That year, an Israeli government commission reviewing the military budget criticized the handling of the barrier's construction and its $2.5 billion cost. Much of the unfinished work involves "fingers" of the barrier around Jewish settlements deep in the West Bank, potentially controversial in a climate in which the Obama administration is trying to curb Israeli activity in the West Bank as a prelude to restarting peace talks.

That is little consolation in Maale Adumim, where debate over the barrier's route and completion shows that the project has gone beyond a simple matter of security and entered the fabric of daily life and politics.

Shlomo Lecker, an Israeli lawyer who opposed construction of the barrier here on behalf of Palestinian clients, said the route had less to do with security and more with securing "as much land as possible" for the settlement.

Maale Adumim Mayor Benny Kashriel said he has little doubt that "the route of the barrier will determine the future border between us and the future Palestinian state" -- despite official Israeli policy that the wall's route is irrelevant to final border negotiations. Of more practical concern, he said, is that, in the absence of the barrier, residents of Maale Adumim must pass through an Israeli border police checkpoint to enter Jerusalem -- the same checkpoint used by Palestinians who want to enter Israel.

"It's a daily nightmare for our residents," Kashriel said. "Sometimes it can take an hour and a half to get to work."