Four and a half years after the outbreak of the second intifada, Israel and the Palestinian Authority have signed a cease-fire agreement in Sharm el Sheik, and the peace process appears to be reviving. The question, as ever, is whether the process will bring peace. Considering the fate of the “road map,” which disintegrated three months after being unveiled with great ceremony in June 2003, it’s hard not to feel a weary sense of déjà vu. In the days following the Sharm el Sheik summit, continued flare-ups on both sides underscored the fragility of the cease-fire.

And yet, the dynamic has changed considerably since 2003. At that time Israeli Prime Minister Ariel Sharon made no secret of his opposition to the road map. It was precisely to silence the growing anti-occupation clamor and kill the road map–to put it “in formaldehyde,” as a top adviser recently admitted–that Sharon made the fateful decision to remove all settlers from the Gaza Strip. He needs a cease-fire to avoid the impression that Israel is leaving under fire, as it did in southern Lebanon in 2000.

The Palestinians, for their part, are exhausted after four and a half years of living under siege. Mahmoud Abbas, the newly elected Palestinian Authority president after the death of Arafat, has stated unequivocally that the armed intifada has only damaged the liberation struggle. Though deeply mistrustful of Israeli intentions, Palestinians made clear in the January vote that they are willing to give Abbas’s path of negotiation a chance. Abbas is wagering that a cessation of Palestinian violence will compel Israel to re-enter serious negotiations toward a two-state solution to the conflict.

Despite its flamboyant rhetoric, the militant Islamist group Hamas–mauled by Israel’s assassination campaign and keenly grasping the shift in mood–has said it will observe the cease-fire. Hamas has an additional reason to lay down arms: This summer the organization will participate in the PA’s legislative elections for the first time; widely respected for its charitable work and lack of corruption, Hamas is expected to do well. This would mark a historic transformation, since the organization would be joining the PA power structure and would thus assume responsibility not only for governing but for implementing agreements with Israel.

That’s the good news. The bad news is the factors working to undermine the cease-fire. For one, Sharon has insisted that Abbas not merely enforce a cease-fire but also crush Hamas and its militant allies. This would spark a civil war that Abbas has no intention of provoking. The prisoner issue is another potential pitfall. Palestinians are insisting on the release of a significant percentage of the roughly 8,000 now being held, not just a few hundred token releases. Palestinians are also looking for an easing of the checkpoints and closures, which have suffocated economic life.

But the greatest weakness of the Sharm el Sheik agreement is that it fails to address the root of the conflict: the thirty-eight-year occupation. Even if Sharon succeeds in removing Gaza’s 8,000 settlers, there will still be some 400,000 in the West Bank and East Jerusalem. Sharon has made clear he has no intention of relinquishing those lands. Even as Sharon and Abbas were shaking hands in Sharm, Israel was rapidly expanding settlements in Greater Jerusalem and expropriating land elsewhere in the West Bank to extend the separation wall. If these trends continue, frustration will build once again among Palestinians, and Abbas will find it increasingly difficult to convince them that their basic rights can be achieved through negotiation rather than violence.

Constructive US intervention is desperately needed. Reviled in the Arab and Muslim worlds for its support of Israel’s occupation, the United States would benefit enormously from brokering a just peace, as George W. Bush will surely be told by foreign leaders during his upcoming European trip. It’s an improbable scenario, but without US pressure on Sharon, the cease-fire will go the way of the road map, and resentment toward Washington will grow.