For months now, the Palestinian terror group Hamas has been shelling Israeli cities with little in the way of an assertive response. But this weekend, which capped a week when at least 300 Hamas-fired rockets and mortars pounded southern Israel, the Israeli government has at last decided to retaliate.

“Operation Cast Iron” opened on Saturday with a carefully planned, perfectly coordinated, and devastating air strike against Hamas targets in Gaza. The strike, which involved more than 100 aircraft and occurred in two waves, destroyed dozens of military and police headquarters, training camps, and above-ground and underground weapons facilities. If Hamas estimates are to be believed, approximately 200 Palestinians have been killed. Of these, a great majority appear to have been terrorist combatants. Israel has also bombed the Islamic University in Gaza, and is now threatening a full-scale invasion.

The weekend offensive marks the third time in less than a decade that Israel has opened a war whose proximate cause is terrorist aggression but which was actually fostered by Israel’s own self-delusive policies. For instance, the second intifada, which broke out in September 2000, was made possible by Israel’s Oslo-era policy of inviting terrorist armies, including Hamas, to entrench itself in the West Bank and Gaza. By allowing Hamas to build up its political power base and military capabilities, Israel virtually guaranteed that it would be drawn into a future conflict in Gaza. A similar cycle of cause-and-effect underpinned the second Lebanon War, which broke out in July 2006. That conflict was made possible in large part by Israel’s May 2000 withdrawal from southern Lebanon.

Likewise, Israel’s latest military campaign is the inevitable result of Israel’s ill-conceived “disengagement” from Gaza in August 2005. The flaw of the earlier withdrawal was starkly revealed this Sunday, when sorties against Hamas targets destroyed no fewer than 40 smuggling tunnels between Gaza and the Sinai. These tunnels were a testament to the terrorist activity that Israel’s withdrawal had made possible.

Seen against the background of Hamas’s resurgence, this weekend's successful strikes are long overdue. So, too, is the chastening that they signal within Israel’s political leadership – the triumvirate of outgoing Prime Minister Ehud Olmert, Defense Minister and Labor Party Chairman Ehud Barak, and Foreign Minister and Kadima leader Tzipi Livni – which appears finally to have grasped that Hamas cannot be stopped with economic pressure and temporary ceasefires. As Barak told Fox News this weekend, “For us to be asked to have a ceasefire with Hamas is like asking you to have a ceasefire with al-Qaeda. It's something we cannot really accept.” Meanwhile, Livni reportedly said that Islamists must be drummed out of Gaza’s leadership.

This newfound resoluteness is to be welcomed. But the fact that Israel’s leaders have come to realize the urgency of confronting terrorism does not compensate for the dismal failures of their past performance. Reports indicate that Saturday’s strike relied on lengthy planning and intelligence gathering, but they don’t settle the question of how the government could have waited so long to act – particularly when 250,000 Israeli citizens had been living so long under a relentless barrage of rockets and mortar fire. The new Israeli offensive must also be considered in the context of the Olmert government’s bungled war against Hezbollah in 2006, when the limited success of an initial aerial bombardment was succeeded by a less successful ground offensive and, ultimately, a tenuous ceasefire.

Early evidence suggests that the government has recognized its past mistakes, and is intent on avoiding them. Thus Olmert, Barak, and Livni have defined Operation Cast Iron’s goals narrowly, eschewing the bombastic statements that the Olmert government made when the second Lebanon War erupted. Operation Cast Iron is designed to put an end to Hamas's rocket fire, terrorist activity, and arms smuggling.

However, questions abound. Will Barack and Livni follow through with their rhetoric about toppling Hamas, or will they be content to leave it in power after a temporary show of strength? If the latter, who will stop the weapons smuggling or prevent Hamas from recuperating militarily and preparing to drag Israel into its next confrontation?

Just as pressingly, who will take over if Israel does depose Hamas in a ground invasion? On the one hand, Olmert, Barak, and Livni remain allergic to the idea of Israel’s long-term reoccupation of parts or all of Gaza. But the possible alternatives are troubling. For instance, the experience of the United Nations Interim Force in Lebanon in southern Lebanon, which shields instead of thwarts Hezbollah’s ongoing empowerment, argues against the idea of NATO or other international forces taking over Gaza. Similarly, Israel should avoid replacing Hamas with Mahmoud Abbas and his Fatah-run Palestinian Authority. Gaza’s transfer from anti-Israeli Hamas to anti-Israeli Fatah is in fact no solution, because even if Fatah presently lacks Hamas's energy and discipline, it can nevertheless be relied on to instill hatred of Israel in future generations of Palestinians, just as it currently does in the West Bank.

Still another troubling possibility is that, with Israeli elections tentatively scheduled for February 10, a perceived successful outcome to the war would help the current government defeat the Likud party, most of whose current lineup opposed the “disengagement” that created the current crisis in the first place. Given the Likud leadership’s foresight in this regard, it would be unfortunate if the next government did not share its grasp of the threats to Israeli security – especially at a time when, however grave the Gaza threat, the incomparably greater Iranian threat could require critical decision-making by the spring of 2009.

It is hard to trust the very people who got Israel into its mess in Gaza to get the country out of it. A viable solution to Gaza may involve Israel reoccupying its most strategic parts—the Gaza-Sinai border and the northern Strip from which most of the rockets are launched—while putting any Gaza regime on notice that continued aggression will result in further Israeli conquests. While such a solution may seem uncompromising, it is in fact greatly preferable to the successive retreats and empty “ceasefires” that have defined Israeli policy in Gaza to date. Unfortunately, it is a solution that requires the kind of political courage that has not been the hallmark of Israel’s current leadership.