Security is the only justification for building a separation fence between the state of Israel and the West Bank - to protect the cities of Israel and its main roads from terrorists who freely cross the Green Line. Such a fence exists around Gaza and stops terrorists from entering Israel from the strip and practically nobody disputes its contribution to security.

A year ago, work began on the northern section of the fence, from Kafr Salem to Elkana, and now the central section, from Elkana to the outskirts of Jerusalem, awaits government approval. The fence planners have proposed several alternatives, with the shortest and cheapest closely following the Green Line, with some relatively modest topographic and demographic corrections, and the most ambitious plan encompassing the Trans-Samarian Highway and including the city of Ariel.

After the Aqaba summit, it became clear that U.S. President George W. Bush is opposed to the fence, particularly along its proposed route. British Prime Minister Tony Blair also leveled veiled criticism at the fence during the weekend. "We are interested in progress in the peace process that will render the fence's security arrangements unnecessary," he said.

These positions taken by the leaders of the U.S. and Britain take into account the vehement Palestinian opposition to the fence, but are mostly based on concern about political facts being made permanent by the fence. The Palestinians oppose the fence because of their substantive objection to their territory being fenced, and because there are cases where the twisting route encompasses settlers beyond the Green Line and harms farmlands, local water rights, the livelihood and the standards of living on the Arab residents of towns and villages along the fence.

The separation fence is a necessary security measure and that's how it should be regarded - and not as an instrument to annex parts of the West Bank to Israel. Therefore, the fence should follow the Green Line as closely as possible and certainly not extend deep into the West Bank so it can include a city like Ariel. If it does that, then it won't be a security fence but a fence meant to express the annexation ambitions of the settlers. Both from the security and economic aspects, such a fence would be very expensive and ineffective because it will be difficult to monitor its full length.

The settlers' pressure to extend the fence into the West Bank is one of the factors delaying the government's approval of the final route and Prime Minister Ariel Sharon, trapped between the contradictory pressures of the settlers and their opponents, meanwhile is delaying the construction project.

For the fence to fulfill its security purpose as quickly as possible and to remove international reservations about it such as those raised by Bush and Blair, the prime minister and his government should reject the demands to move the fence eastward and stick to its original purpose, along the Green Line.