"If the casualty reports are accurate, Hamas is going to respond. And this isn't a two- or three-day deal in which the genie is put back in the bottle," said Aaron David Miller, a Middle East scholar at the Woodrow Wilson International Center for Scholars and author of "The Much Too Promised Land." "This takes the already slim chance of an early, active and successful Obama engagement on Israel-Palestinian peace and lowers it to about zero."

Israel has been warning for weeks that it could not tolerate regular rocket attacks launched from Hamas-controlled territory in the Gaza Strip, and it has been laying the groundwork for a new offensive with the collapse this month of a shaky six-month cease-fire. Still, the ferocity and scope of today's Israeli attacks, which killed more than 200, appeared to stun Western governments and analysts. Arab countries condemned Israel, and Saudi Arabia urged the United States to intervene to stop the attacks.

But in official statements, the Bush administration blamed Hamas, which it classifies as a terrorist group, cautioning Israel only to avoid hurting innocent civilians.

"We strongly condemn the repeated rocket and mortar attacks against Israel and hold Hamas responsible for breaking the ceasefire and for the renewal of violence there," Secretary of State Condoleezza Rice said in a statement. "The ceasefire must be restored immediately and fully respected. The United States calls on all concerned to protect innocent lives and to address the urgent humanitarian needs of the people of Gaza."

President-elect Barack Obama has voiced sympathy with Israel's predicament. During his visit to Israel last summer, he held a news conference in Sderot, the southern Israeli town that has borne the brunt of the Gaza rocket attacks, saying he does not "think any country would find it acceptable to have missiles raining down on the heads of their citizens."

"If somebody was sending rockets into my house where my two daughters sleep at night, I'm going to do everything in my power to stop that," Obama said at the time. "And I would expect Israelis to do the same thing."

Obama's transition team was more cautious today, adhering to its policy of not commenting on foreign developments because there should be "one president at a time." Brooke Anderson, Obama's national security spokeswoman, said only that Obama "is closely monitoring global events, including the situation in Gaza."

Rice also briefed the president-elect by phone today.

There is little doubt, however, that if the situation escalates, it could hand yet another potential crisis to Obama, who will already be inheriting wars in Iraq and Afghanistan and an unstable situation in Pakistan. If the past is any guidance, the United States will probably come under great pressure to restrain Israel if the tit-for-tat violence grows.

One senior Bush administration official said he believes the Israelis acted now in Gaza "because they want it to be over before the next administration comes in." While Bush has largely been supportive of almost any Israeli action taken in the name of self-defense, this official pointed out: "They can't predict how the next administration will handle it. And this is not the way they want to start with the new administration."

This official, who was not authorized to speak publicly, said the Israelis are being vague about how long the offensive will last but have hinted it could continue well into the week. "I think the Israeli goal now is to damage Hamas enough so that Hamas will accept a real truce," this official said. "I think it's a plausible goal. They are not trying to overthrow Hamas. They are not trying to take over the Gaza Strip."

But other U.S. analysts were skeptical the Israeli offensive would succeed in intimidating Hamas. "By now Israel should have realized that [this kind of attack] rarely has any decisive effect," said Anthony H. Cordesman, a military analyst at the Center for Strategic and International Studies. "At best you get another faltering cease-fire, and then the whole thing begins again. Both sides have been escalating to nowhere."

Cordesman agreed with Miller that the prospects of a larger peace deal have probably been set back. Bush-brokered peace talks between the Palestinians and Israelis have made some progress, but the two sides remain apart on key issues, and it is unclear what approach Obama will take to try to bridge the divide. Bush has focused on helping build up the Palestinian Authority, which controls the West Bank, but it's unclear how any peace deal would address the situation in Gaza, which is controlled by Hamas.

"Now I think what the Obama administration faces is at least two years or more before they can really think of having any serious movement" on the peace process, Cordesman said. "Every time this kind of violence breaks out, it becomes harder to move forward. It just creates more of a climate of hostility and anger."

The Washington Post