ATRUCE between Israel and Hamas was to begin this morning in the Gaza Strip, ending daily barrages of rockets that have terrorized nearby Israeli towns as well as counterstrikes that have killed more than 350 Palestinians this year. In accepting the Egyptian-brokered deal, Israel embraced the least bad of the limited options it has for countering Hamas, which has been turning Gaza into a fortified base for advancing the cause of Islamist extremism in the region -- a cause it shares with Iran. For a while, Israeli civilians will be relieved from having to duck into bomb shelters, and Gazans will be better supplied with food and other essential goods. How long the peace lasts, and whether it does more good than harm, will depend on how well Israel and Hamas's moderate Palestinian rivals use the calm.

In political terms, Hamas is the immediate beneficiary of the deal -- one reason the government of Prime Minister Ehud Olmert was slow to agree to it. One year after it drove out the secular administration of President Mahmoud Abbas, the Islamist movement has consolidated control over Gaza and demonstrated that it can force Israel into acknowledging its authority. If a border crossing with Egypt is reopened, as the agreement contemplates, relatively normal life and commerce could resume in the territory. Mr. Abbas, who was already planning a visit to Gaza to discuss a rapprochement with Hamas's leadership, will now do so from a weaker position.

The strategy of both Israel and the United States has been to strengthen Mr. Abbas and his West Bank-based Palestinian Authority against Hamas, by matching a blockade of Gaza with measures to improve conditions in the West Bank and negotiations to create a Palestinian state. Unfortunately, little progress has been made on the second front -- though that is where the Bush administration has concentrated its effort. Israel has been reluctant to loosen its security grip on the West Bank and slow to dismantle even those Jewish settlements it has deemed illegal. While the peace negotiations have been conducted in secret since late last year, most public indications are that they have not advanced far.

At best, Mr. Olmert and Mr. Abbas would now press to complete a peace deal, so that the Palestinian president would have a tangible and attractive alternative to offer to Hamas's promise of endless "resistance" to the Jewish state. Some hope that an accord between the two Palestinian factions could give Mr. Abbas leeway to close the deal for statehood. Yet Mr. Olmert, who has been badly weakened by scandals, appears more interested in brokering a prisoner exchange with Hezbollah and in conducting long-shot peace talks with Lebanon and Syria than in making tough decisions about matters such as the future of Jerusalem. Both Israel and its Iranian-backed enemies are maneuvering for tactical advantage, trying to bolster their positions as they await a new U.S. president. They have not averted the major conflict that has threatened the region for the last couple of years -- only postponed it.