When it was launched last December, Israel's invasion of the Gaza Strip looked to most people in Washington to be risky, counterproductive and doomed to futility. Not only pundits like me but senior officials of the Bush administration predicted that the Israeli army would not succeed either in toppling Gaza's Hamas government or in eliminating its capacity to launch missiles at Israeli cities. Instead it would subject the Jewish state to another tidal wave of international opprobrium and risk its relations with West Bank Palestinians and Egypt.

Mostly, we were right. But today, Operation Cast Lead, as the three-week operation is known in Israel, is generally regarded by the country's military and political elite as a success. The reasons for that are worth examining now that a new and even more hawkish Israeli government is weighing whether to flout Washington's prevailing opposition to a military attack on Iran.

Israel's satisfaction starts with a simple set of facts. Between April 2001 and the end of 2008, 4,246 rockets and 4,180 mortar shells were fired into Israel from Gaza, killing 14 Israelis, wounding more than 400 and making life in southern Israel intolerable. During what was supposed to be a cease-fire during the last half of 2008, 362 rockets and shells landed. Meanwhile, between late 2000 and the end of 2008, Israeli forces killed some 3,000 Gazans.

Since April there have been just over two dozen rocket and mortar strikes -- or less than on many single days before the war. No one has been seriously injured, and life in the Israeli town of Sderot and the area around it has returned almost to normal. Israeli attacks in Gaza have almost ceased, too: Since the end of the mini-war, 29 Palestinians, two of whom were civilians, have been killed by Israeli action.

Hamas, of course, remains in power and unmoved in its refusal to recognize Israel. It is still holding an Israeli soldier who was abducted in 2006. It is still smuggling material for weapons through tunnels under the Egyptian border and, if it chose to, could resume rocket attacks on Israel at any time.

The point, however, is that Israel has bought itself a stretch of relative peace with Hamas, just as its costly 2006 invasion of Lebanon has produced three years of quiet on that front. From the Israeli perspective, a respite from conflict is the most that can be expected from either group -- or from their mutual sponsor, Iran.

"They will never change their ideology of destroying Israel," a senior government official told me last week. "But you can deter them if they are convinced you are not afraid of fighting a war."

But what of the grievous Palestinian suffering in the invasion -- Israel itself counted 1,166 dead Gazans, including more than 450 civilians -- and the international backlash that has caused? Just last week a U.N. commission headed by South African jurist Richard Goldstone condemned what it called "a deliberately disproportionate attack designed to punish, humiliate and terrorize a civilian population," and suggested that responsible Israelis be hauled before the International Criminal Court on war crimes charges.

Israel's leaders worried a lot about losing the war that way. But as they see it, they suffered only scratches. Egypt, which quietly collaborates with Israel's blockade of Gaza, came under pressure to change its policy but held firm. No Arab country toughened its stance toward Israel: According to the Obama administration, as many as five may be willing to offer diplomatic and economic concessions if Israel freezes its West Bank settlement construction.

Perhaps most significant, Hamas's rival for Palestinian leadership, the West Bank-based Palestinian Authority, is considerably stronger than it was before the war. Probably it will renew peace talks with Israel within weeks. As for the Goldstone report, the heat it briefly produced last week will quickly dissipate; the panel was discredited from the outset because of its appointment by the grotesquely politicized U.N. Human Rights Council.

The Gaza invasion was the second military operation Israel embarked on in less than 18 months despite disapproval from Washington. The other was its bombing of a nuclear reactor under construction in Syria in September 2007. Then, too, officials in Washington feared a dire diplomatic backlash or even a war between Israel and Syria. Nothing happened.

As they quietly debate the pros and cons of launching a military attack on Iran's nuclear facilities, Israel's political and military leaders no doubt will be thinking about that history. That doesn't mean they will discount American objections -- Iran would be a far harder and more complex target, with direct repercussions for U.S. troops and critical interests in the region. But, as with Gaza, even a partial and short-term reversal of the Iranian nuclear program may look to Israelis like a reasonable benefit -- and the potential blowback overblown.