JERUSALEM, January 27, 2012 — Israeli intelligence estimates, backed by academic studies, have cast doubt on the widespread assumption that a military strike on Iranian nuclear facilities would set off a catastrophic set of events like a regional conflagration, widespread acts of terrorism and sky-high oil prices.

The estimates, which have been largely adopted by the country’s most senior officials, conclude that the threat of Iranian retaliation is partly bluff. They are playing an important role in Israel’s calculation of whether ultimately to strike Iran, or to try to persuade the United States to do so, even as Tehran faces tough new economic sanctions from the West.

“A war is no picnic,” Defense Minister Ehud Barak told Israel Radio in November. But if Israel feels itself forced into action, the retaliation would be bearable, he said. “There will not be 100,000 dead or 10,000 dead or 1,000 dead. The state of Israel will not be destroyed.”

The Iranian government, which says its nuclear program is for civilian purposes, has threatened to close the Strait of Hormuz — through which 90 percent of gulf oil passes — and if attacked, to retaliate with all its military might.

But Israeli assessments reject the threats as overblown. Mr. Barak and Prime Minister Benjamin Netanyahu have embraced those analyses as they focus on how to stop what they view as Iran’s determination to obtain nuclear weapons.

No issue in Israel is more fraught than the debate over the wisdom and feasibility of a strike on Iran. Some argue that even a successful military strike would do no more than delay any Iranian nuclear weapons program, and perhaps increase Iran’s determination to acquire the capability. Security officials are increasingly kept from journalists or barred from discussing Iran. Much of the public talk is as much message delivery as actual policy.

With the region in turmoil and the Europeans having agreed to harsh sanctions against Iran, strategic assessments can quickly lose their currency. “They’re like cartons of milk — check the sell-by date,” one senior official said.

But conversations with eight current and recent top Israeli security officials suggested several things: since Israel has been demanding the new sanctions, including an oil embargo and seizure of Iran’s Central Bank assets, it will give the sanctions some months to work; the sanctions are viewed here as probably insufficient; a military attack remains a very real option; and postattack situations are considered less perilous than one in which Iran has nuclear weapons.

“Take every scenario of confrontation and attack by Iran and its proxies and then ask yourself, ‘How would it look if they had a nuclear weapon?’ ” a senior official said. “In nearly every scenario, the situation looks worse.”

The core analysis is based on an examination of Iran’s interests and abilities, along with recent threats and conflicts. Before the United States-led war against Iraq in 1991, Saddam Hussein vowed that if attacked he would “burn half of Israel.” He fired about 40 Scud missiles at Israel, which did limited damage. Similar fears of retaliation were voiced before the Iraq war in 2003 and in 2006, during Israel’s war against Hezbollah in southern Lebanon. In the latter, about 4,000 rockets were fired at Israel by Hezbollah, most of them causing limited harm.

“If you put all those retaliations together and add in the terrorism of recent years, we are probably facing some multiple of that,” a retired official said, speaking on the condition of anonymity, citing an internal study. “I’m not saying Iran will not react. But it will be nothing like London during World War II.”

A paper soon to be published by the Institute for National Security Studies at Tel Aviv University, written by Amos Yadlin, former chief of military intelligence, and Yoel Guzansky, who headed the Iran desk at Israel’s National Security Council until 2009, argues that the Iranian threat to close the Strait of Hormuz is largely a bluff.

The paper contends that, despite the risks of Iranian provocation, Iran would not be able to close the waterway for any length of time and that it would not be in Iran’s own interest to do so.

“If others are closing the taps on you, why close your own?” Mr. Guzansky said. Sealing the strait could also lead to all-out confrontation with the United States, something the authors say they believe Iran wants to avoid.

A separate paper just published by the Begin-Sadat Center for Strategic Studies says that the fear of missile warfare against Israel is exaggerated since the missiles would be able to inflict only limited physical damage.

Most Israeli analysts, like most officials and analysts abroad, reject these arguments. They say that Iran has been preparing for an attack for some years and will react robustly, as will its allies, Hezbollah and Hamas. Moreover, they say, an attack will at best delay the Iranian program by a couple of years and lead Tehran to redouble its efforts to build such a weapon. NYT