There can be no doubt that the Hamas leaders in Gaza brought this on themselves. Recent rocket attacks from the Strip no longer made any pretence of being perpetrated by more extreme Salafists and assorted jihadists. Rather than distance itself from the attacks, Hamas has been taking the credit for sending up to one million Israelis in the Gaza periphery into safe rooms and shelters. The reason for this new boldness is presumably Hamas's close relationship with the ruling Muslim Brothers in Egypt.
The Netanyahu-Barak duo, under pressure from the Israeli public to retake the initiative and reestablish deterrence, succeeded this time in surprising Hamas and scoring effective initial hits: the targeted assassination of Hamas military leader Ahmed Jaabari and the destruction of at least some of Hamas's Iranian-supplied Fajr rockets that are capable of hitting Tel Aviv. So far, so good.
So why am I worried? First and foremost, because our leadership still has no viable strategy for dealing with Hamas in Gaza. Even the objectives of this offensive as outlined by Defense Minister Barak Wednesday evening—strengthening deterrence, destroying rockets, hurting the terrorist organizations, defending the Israeli civilian rear—are tactical and temporary, not strategic. Having tried and failed to choke Hamas economically, having invaded the Strip four years ago at a heavy price in international condemnation without achieving more than a few months' peace and quiet, and having undertaken, along with the Quartet, not to talk to Hamas (which in any case won't talk to Israel), the Olmert and Netanyahu governments have for five years (since Hamas's takeover of Gaza) sufficed with tactics, not strategy.
The most this operation can do is achieve a few more months of quiet that will get Netanyahu and Barak through the coming elections. By demonstrating that the PLO does not control Gaza, it might also slightly damage that organization's credibility as it seeks U.N. recognition for a state that comprises Gaza. That's the best case. It assumes that Hamas will not seriously escalate and cause heavy loss of life in Israel. It also assumes that an errant bomb won't accidentally kill a bunch of kids in Khan Yunis or Rafah, thereby bringing down upon us the wrath of the world.
And then there is Egypt. This operation is the first serious test of the validity of President Morsi's commitment to look after the Gazans. So far, Egypt under the Muslim Brotherhood has withdrawn its ambassador. If it weakens relations in a more substantive way—e.g., by closing down military cooperation with Israel regarding the salafists in Sinai—the damage at the strategic level could quite profoundly hurt Israel's broader strategic interests.
As always, it's easy to go in, but hard to get out.