As they prepared for lightning airstrikes on the Hamas-ruled Gaza Strip, Israel's leaders drew sobering lessons from their stalemate against another Islamic paramilitary force, Lebanon's Hezbollah guerrillas.
In that setback in the summer of 2006, Israel rushed to battle without a detailed plan or realistic goals, and was handed its first failure to vanquish an Arab foe in war. Hezbollah not only withstood the 34-day offensive, but it also emerged stronger politically.
Faced with frequent Hamas rocket fire across its southern border, Israel planned its Gaza operation more meticulously, over nearly two years. As a result, Israeli officials said Sunday, their intelligence services developed a longer list of targets to bomb, enabling the air force to inflict more damage on the militant Palestinian group before Israel contemplates a risky ground assault.
And instead of boasting that they would "destroy" the enemy, as they did in the case of Lebanon, Israeli leaders set the more modest aim of "improving the security" of terrorized Israeli communities.
That less ambitious approach could make it easier for Israel to withdraw from the conflict on its terms, avoiding the kind of demoralizing stalemate that developed in Lebanon.
So far, Israel considers its Gaza offensive a success. Since it began Saturday, waves of airstrikes have destroyed dozens of Hamas paramilitary facilities, weapons-smuggling tunnels from Egypt and underground rocket-launching sites. Rocket fire from Gaza has diminished well below what was once considered Hamas' capacity.
Although many risks and uncertainties lie ahead, in particular the specter of getting bogged down in a ground war, the offensive has brought Israel to a psychological turning point, restoring a measure of the country's confidence in its capacity to confront armed adversaries.
"Hamas is dazed and confused and has no explanation to offer its people," Amos Gilad, a senior Israeli Defense Ministry official, told Israel Radio on Sunday. "But we must refrain from bragging and marking dramatic objectives."
Rather than remove Hamas from power, he and other Israeli officials say, the goal is to weaken the movement and demonstrate the price it would pay for continuing to launch rockets. Sooner or later, Israel hopes to restore and strengthen an Egyptian-brokered cease-fire that worked for nearly five months before it started to break down in November.
"The army doesn't even have the pretense of neutralizing Hamas' ability to launch rockets. We have tried that before and failed," said Alon Ben-David, military correspondent for Israel's Channel 10 television.
"This operation," he explained, "is directed at Hamas' motivation to fire rockets at Israel rather than its actual ability to do so."
For reasons that became evident during the Lebanon conflict, it is far from certain whether even that limited goal can be achieved.
Hamas leaders have gone into hiding but given no hint of backing down. On the contrary, they have threatened to wage suicide attacks in Israel for the first time since 2005, apparently by infiltrating from the West Bank or from Gaza by way of Egypt.
"The ostensible aims of the operation amount to requiring Hamas not to behave like Hamas: not to fire into Israel or target Israeli civilians or soldiers, not to prepare for such attacks, not to store or smuggle in the material for such attacks," David Horovitz, editor of the Jerusalem Post, wrote in a Sunday editorial. "And that is not going to be achieved quickly."
Israeli officials have indicated that the offensive could last weeks or months. But as details of civilian casualties emerge from Gaza, Israel is coming under international pressure to halt the operation, just as it did in Lebanon. Health Ministry officials in Gaza estimate that as many as a third of the dead are noncombatants.
And it remains to be seen whether Israeli leaders have prepared adequately for the complications that may lie ahead if their army launches a ground campaign against Hamas' 15,000-man paramilitary force, which has drawn its own lessons from Hezbollah's success in the Lebanon war.
Anticipating a Lebanon-style ground war, Hamas used the recent cease-fire to fortify its military posts in Gaza, dig underground bunkers, acquire a large number of antitank missiles and install them in foxholes. How much of that defensive weaponry remains intact is unclear.
Israeli analysts believe an Israeli ground offensive is only a matter of time. The Lebanon war demonstrated that Israel's air force alone could not stop Hezbollah from lobbing rockets across the border.
But analysts also agree that a ground operation in the densely populated enclave would be messy, carrying the risk of an even higher civilian death toll and heavy casualties to Israeli soldiers. Hamas, which is still holding an Israeli soldier it captured in June 2006, is believed to have plans to try seizing others entering Gaza.
Despite support across Israel's political spectrum for a strong response to Hamas, many Israelis are wary of a prolonged offensive.
"How many soldiers are expected to be killed in the first wave?" columnist Zvi Barel asked in Sunday's Haaretz newspaper. "How many months is the [army] expected to spend in Gaza, sweeping its houses and tunnels? How many Palestinian civilians will be killed?"
Reuven Pedatzur, head of the security studies program at Israel's Netanya College, said the longer Israel fights in Gaza, the more difficult it will become to justify withdrawing.
"Yes, the operation started successfully, but we need to ask ourselves how we get out and arrive at negotiations," he said.
Such decisions now rest in the hands of Prime Minister Ehud Olmert and Defense Minister Ehud Barak. Olmert had been elected just four months before the Lebanon war and later endured censure by a government-appointed panel for the way he and his top aides had conducted it. Amir Peretz, the wartime defense minister, later stepped down.
Disgraced by corruption charges and forced in September to resign, Olmert remains a caretaker leader with a major military conflict on his agenda before elections in February to choose his successor.
Israeli commentators who watched him announce the offensive Saturday said he looked more subdued than the overconfident leader who addressed the nation at the start of the Lebanon war.
"Olmert was a serious, reserved man, who has learned that some situations call for modesty," columnist Sima Kadmon wrote on Ynet, a news website. "His words lacked the grandiose promises made on the eve of the Lebanon war."