Israel has opted to launch a major attack on Hamas in Gaza. The idea appears to be to use heavy military force, primarily from the air, but with a limited objective: to weaken Hamas to a point where it returns to a cease-fire on conditions congenial to Israel. The opening conditions were favorable from Israel's standpoint: It achieved tactical surprise in launching a Sabbath attack while much of the world was busy with Christmas and New Year celebrations. The United States has been supportive and is in any case between administrations; Prime Minister Ehud Olmert's recent visit to Turkey gave Syria an incentive not to meddle; Egypt has shared Israel's frustration with Hamas and seemingly - through Foreign Minister Tzipi Livni's meeting with President Hosni Mubarak on the eve of the attack - gave its blessing. The Israeli political scene, both (Zionist) left and right, has been supportive, to the extent of setting aside the current election campaign.

Militarily, Israel ended up with little alternative but to respond to Hamas rocket attacks. Even Egyptian mediators between Israel and Hamas agreed that the latter had unilaterally broken a cease-fire. Hamas seemed to believe it could fire rockets at Israeli civilians with impunity, while arming and fortifying Gaza and flouting Egypt's invitation to negotiate a unity government with the Palestine Liberation Organization.

Yet the difficult part for Israel is to attack, achieve something, then get out. Minister of Defense Ehud Barak and military Chief of Staff Gabi Ashkenazi are clearly not anxious to get drawn into ambiguous ground warfare that could multiply Israeli losses and lead to a reoccupation of Gaza. Nor is the Israeli public or body politic interested in renewed, open-ended occupation of 1.5 million Palestinians in the territory, or even a portion thereof. On the other hand, the ghost of Israel's failed war against Hizbullah in 2006 hovers over this operation: It must end by strengthening Israel's deterrent profile against the militant Islamists.

At the end of the day, however, the operation only confirms that neither Israel nor anyone else has a long-term workable strategy for dealing with Hamas in Gaza. This is a militant organization that has taken over a piece of Palestinian territory but refuses to behave like a sovereign power and, ultimately, glories in the victimhood or martyrdom of its people. Terms like victory, defeat and peace negotiations are irrelevant here. At its best, operation "Cast Lead" (the Hebrew term relates to the current Hanukah holiday, besides sounding appropriate in military terms) will deliver a few more months of cease-fire and tenuous coexistence between Islamist Gaza and its surroundings. Indeed, the operation apparently doesn't aspire to achieve more than that.

And at its worst? The attack on Gaza could, particularly if it is prolonged over weeks as Barak threatens, inflame anti-Israeli and anti-Western sentiments throughout the Arab and Muslim worlds. Rioting could spread across the West Bank and among Palestinian citizens of Israel. Hizbullah could open a second front in the north, and terrorists could attack anywhere. Hamas rockets will almost certainly continue to rain down in an expanding circle around Gaza (Israeli military planners, learning from the Lebanon war, have cautioned that this operation cannot stamp out rocket fire militarily). Finally, Hamas could refuse to renew the cease-fire, despite its losses. The war in Gaza could become a major election issue in Israel. And it could end up as Barack Obama's first presidential crisis.

In the fog of war, alternative strategies look more distant than ever. Yet they are worth recalling. One is to open up the Gaza passages and cease inflicting ineffective collective punishment on 1.5 million Gazans, making clear that Israel's quarrel is only with the Hamas military and political leadership in Gaza and beyond. Once the military operation is over, and assuming Israel emerges from it in a position of strength, that would be the time to take such a step.

Another is to seek direct talks with Hamas, on the assumption that the movement is here to stay and cannot be ignored forever. This is not simple: Most (but not all) Hamas leaders don't want to talk to Israel; those who do have a limited and problematic agenda that does not include recognition of Israel or peace. Then too, Israel has to be careful not to undercut the leadership of Palestinian President Mahmoud Abbas, who does recognize Israel and does want peace. Still, this option must find a place on Israel's strategic agenda, if only in the form of informal, unofficial contacts.

Finally, if nothing else works and Israeli vulnerability to Hamas rockets expands in an increasingly broad radius around the Gaza Strip, Israel may indeed end up having to face the option it fears the most: reoccupation of all or part of Gaza, with the goal of militarily eliminating Hamas. The price would be heavy losses on both sides and an open-ended occupation without an exit strategy. Everyone would condemn Israel; nobody would volunteer to take Gaza off its hands. Hamas, for its part, is counting on Israeli reticence to invoke this option, which would set us and the Middle East back by 40 years.