In Israel, the debate over whether to attack Iran is reaching a fever pitch.

Officials there say the time to make a decision about an Israeli attack is now. They say Iran’s nuclear program, combined with its anti-Israel rhetoric, is a threat to Israel’s very existence.

While American officials oppose an Israeli-led strike, Israel is bracing itself for a potential Iranian counterattack.

A few days ago, a flyer arrived in mailboxes across Israel. It said: "this is the absolute last chance to pick up your gas mask. Don’t be left unprotected. Get your gas masks today at a local Jerusalem mall."

About 50 people were waiting in line at the mall. Some had been there for hours.

A man waiting for the mask said he didn’t care, but came to get the masks because his wife wanted them.

“I know nothing is going to happen. They can’t mess with Israel, it’s not a joke,” he said.

Another woman said she was getting the masks because, as a parent, she felt the need to be responsible and wanted to take the necessary precautions. But she said it is life as usual.

There are other signs that Israel is preparing itself for war.

This week the army sent text messages to people across the country — testing its alert system in case officials need to warn civilians about incoming missiles. Tel Aviv’s city hall says it has designated 60 underground parking garages as makeshift bomb shelters for wartime. Even Israel’s main TV news channel says it is looking to build an underground studio to continue broadcasts during wartime.

All of this comes as Israeli officials ratchet up their rhetoric about the dangers of a nuclear Iran.

Israel’s ambassador to the United States, Michael Oren, emphasized that point Wednesday in an interview with Bloomberg News.

“Just today an Iranian general came out and pledged to wipe Israel off the map, and diplomacy hasn’t succeeded. So we have come to a critical juncture where important decisions have to be made,” he said.

The outgoing minister-in-charge of the military’s home front command says Israel should expect a month-long war with hundreds or more of Israeli casualties. And an official who said he met this week with Israel’s prime minister and defense minister says they intend to make a decision about an Iranian strike before November.

Pundits in Israel and a group of writers and intellectuals are accusing Israel’s leaders of warmongering. But in parliament Thursday, Defense Minister Ehud Barak defended the deliberations.

“There isn’t a subject in the last generation, not a matter of peace or war, that has been discussed in more depth and with such attention and even transparency as the Iran question has,” he said.

Israel seems poised for an attack. But the one thing missing is U.S. support, implicit or explicit. Israeli papers report that Netanyahu is willing to back off on an attack if Obama promises to publicly state that the United States will attack Iran if it must. Israeli officials refuse to confirm or deny such a request has been made to the Obama administration.

Israeli military historian Martin van Crevald said Netanyahu and Obama are engaged in a very complicated dance.

“They don’t trust each other. They hate each other, they loathe each other,” he said. “This makes communication very difficult because on the one hand, if you are Netanyahu, how do you stoke the flames without going too far? And if you are Obama, how do you restrain Netanyahu without turning the Iranians off the hook?”

The crux of this debate is whether a nuclear Iran poses an existential threat to Israel? Some Israeli leaders say yes. But van Crevald says no.

Israel is believed to be a nuclear power, he says, and no nuclear power has ever nuked another nuclear power. Not even the most ruthless dictators. The very real threat, van Crevald says, is what could happen if Israel attacks Iran. Iran could respond with a constant stream of missiles for a very long time, and Israel’s economy could grind to a halt.

“One missile a day, two missiles a day. Then a pause. Then another one,” he said. “Just enough to keep Israel semi paralyzed. Falling one here, one there, very unpredictable. This could be the end of Israel.”

That one-missile-a-day scenario is just one of many possibilities experts here are considering. In the days ahead, we’ll probably hear a dozen more.