TEL AVIV, Israel — With a cease-fire appearing to unravel even before it begins, Israel is facing a protracted war under a divided government.

At the insistence of the government’s political opposition and other parties, plans are already under way to launch a formal inquiry in the Knesset into what went wrong in what many here are calling the worst defeat in Israel’s history.

The inquiry also will explore a further indignity: how the Jewish state has come for the first time to agree to negotiate the relinquishment of land, the Shebaa Farms, in direct response to a deliberate act of military aggression.

The cease-fire looked particularly fragile last night, hours before it was set to take effect. The Lebanese Cabinet announced it would postpone a meeting to deploy its army to southern Lebanon after failing to reach an agreement on whether its forces would attempt to disarm Hezbollah, as the U.N. Security Council demanded. Foreign Minister Tzipi Livni has said Israeli troops will not leave southern Lebanon until international and Lebanese forces are ready to replace them.

This confused state of affairs has already led to recriminations in Jerusalem. Aides to Prime Minister Olmert and politicians close to him are saying the army chief of staff, Lieutenant General Dan Halutz, did not present the Security Cabinet with a viable option for an expanded ground war in Lebanon until late last week.

Meanwhile, Israel’s top military officers and Mr. Olmert’s political enemies and rivals are saying, on the contrary, that General Halutz presented a ground war plan more than two weeks ago and the Security Cabinet rejected it.

One of the politicians making the second claim is Housing Minister Meir Shitrit, a member of the Security Cabinet who opposes Mr. Olmert’s plan for an eventual Israeli withdrawal from most of the West Bank.

In an interview yesterday, Mr. Shitrit said, “First, as a member of the Security Cabinet, I am absolutely sure that Halutz presented the ground war option two weeks ago, and it was not approved by the Security Cabinet. They did not accept it. Defense Minister Peretz did not approve it.”

Mr. Shitrit, who said he was optimistic about the U.N. cease-fire, added that he was the only member of the Security Cabinet to vote against expanding the ground campaign at the last minute. “I thought that when the political clock is ticking, within a few days there would be an agreement. Why does there have to be a ground campaign now? I preferred to wait to give diplomacy a chance,” he said.

As a member of the Kadima Party, albeit as a rival of Mr. Olmert’s, Mr. Shitrit’s remarks could signal further internal divisions. Over the weekend, Israeli newspapers highlighted the fact that Mr. Olmert declined a request from his foreign minister personally to represent Israel at the U.N. Security Council debate on a cease-fire resolution.

And the opposition Likud Party has already broken its silence on the war plans. Today, Prime Minister Netanyahu is expected to deliver a blistering assessment of the Olmert Cabinet’s performance in the war thus far.

For their part, Mr. Olmert and his Cabinet are portraying the U.N. ceasefire agreement as a success.

“The achievement of the army is the platform for the agreement,” Mr. Shitrit said. “Remember, Hezbollah had been damaged strongly. Hundreds of fighters were killed, all the headquarters have been demolished, the ammunition and stores of missiles have been destroyed, the launcher systems have been destroyed. And [Sheik Hassan] Nasrallah has suffered big damage. The facts are he was damaged strongly, before this campaign started. He brought disaster on Lebanon. His status will be diminished seriously in Lebanon.”

A former foreign minister and Likud member of the Knesset, Sylvan Shalom, told The New York Sun yesterday that had he known the war would end in the current cease-fire, he would not have supported it.

“The main question is, if we would have known this would be the outcome of the war, would we have started the war? The answer is absolutely negative,” he said. “The main goals were not achieved, to liberate our soldiers, to disarm the Hezbollah, to remove the threat. More than that, the U.N. is now talking about the liberation of Lebanese soldiers, like there is a way to compare Israeli students who are reservists to terrorists.”

The Israeli Cabinet yesterday approved a U.N. cease-fire with Hezbollah, set to begin at 8 a.m. today. The truce, approved by the U.N. Security Council late Friday by a vote of 15–0, would authorize some 15,000 soldiers from the Lebanese army, along with a fortified U.N. force already on the ground, to take over positions now occupied by the Israel Defense Force.

Only 48 hours before his Cabinet approved the cease-fire, Mr. Olmert approved an airlift to the Litani River of soldiers who began to fight their way back to Lebanon’s border with Israel.

Yesterday, a Hezbollah short-range rocket hit downtown Haifa. And while Lebanon’s Cabinet approved the U.N. cease-fire on Saturday, by yesterday Hezbollah Cabinet ministers said the armed militia would not accept terms of the truce that said it should be disarmed.

Secretary-General Annan touted a proposal yesterday that both sides should silence their guns by this morning. But Israeli officials said last night that they expected their soldiers to stay in Lebanon until the U.N. force and the Lebanese army replaces them, as the cease-fire resolution stipulates.

Mr. Shalom said Likud would ask for an investigation into the government’s conduct of the war as soon as the ceasefire takes effect.

“We will be the first to ask for an investigation into the conduct of this government. There are so many questions, not only about the decision to go to war, but how to conduct the war,” Mr. Shalom said. “Even the last decision, after the Security Council passed a resolution, they decided to go to the Litani River. It was a mistake.We should have done this the first day. I cannot understand it.”

Mr. Shalom warned that Mr. Olmert’s Cabinet will emerge from the war severely divided. “There are many cracks in the stability of the coalition. The Israeli public has lost its confidence in the current government. We can hear the voices now saying, ‘Maybe it is time to have a new government,'” he said.