THE SECURITY barrier that Israel began building across the West Bank this week won't deter Palestinian suicide bombers from embarking on their deadly missions. It will only delay them.

Any barricade can be breached, any border penetrated. And while the Israelis won't be using bricks and mortar to wall off their country from the enemy as did the Romans and the Chinese, the impetus behind these barbarous attacks defies physical containment. Palestinian terrorists are using deadly means to force an end to Israel's 35-year occupation of the West Bank and Gaza Strip. And they are a resourceful lot.

That said, yesterday's bus bombing in Jerusalem that killed 19 Israelis illustrates the reason why Prime Minister Ariel Sharon's government has embarked on construction of the security fence.

Israelis ask plainly: Are we not entitled to make it tougher for suicide bombers to enter Israel? The bomber, dispatched by the Islamic militant group Hamas, hailed from the West Bank town of Nablus, about an hour's drive from Jerusalem. Despite the tougher Israeli security measures in place, he got to his destination to detonate his package on a commuter bus.

Mr. Sharon defends the new security barrier -- a combination of chain-link fence, sophisticated electronic surveillance devices, trenches and increased military patrols with a $350 million price tag -- as yet another defensive measure in his war against terrorism. But, of course, the security fence has taken on greater import in this seemingly intractable conflict in which territory and borders are at the heart of the matter. Palestinian officials have decried the fence as the means by which a small, disjointed Palestinian state is created.

They are right to be concerned. With the Palestinian Authority in a shambles, its leader Yasser Arafat reviled and no political solution in sight, who's to say this fence won't become the basis for future borders?

The debates and disagreements about the fence point up once again the lack of a comprehensive strategy to end the bloodshed in the Middle East and to give the Palestinian people a chance to control their destiny in an independent state of their own.

President Bush is poised to deliver a new policy statement on the Middle East. Earlier this year, at the height of terrorist attacks in Israel, when suicide bombers were striking day after day, the president delivered a tough, cogent speech on his expectations for Israel, the Palestinians and their supporters in the Arab world.

Now he needs to offer up more than strong statements, more than a recitation of his oft-spoken beliefs. A substantive strategy to restore some sense of security to Israeli daily life and put Palestinians on the road to a state of their own must be in the offing. Because good fences will never make good neighbors on this stretch of desert. Not now, not ever.