JUDY WOODRUFF: Meanwhile, Iran declared to the International Atomic Energy Agency that it plans to add new centrifuges to speed up uranium enrichment. That's stoked fears in the West and Israel that Iran is closer to acquiring a nuclear weapon.
Tonight, Margaret Warner, on assignment in the Middle East reports on the growing debate within Israel about how much of a threat Iran really is.
MARGARET WARNER: Prime Minister Benjamin Netanyahu strode on stage last week a chastened victor in parliamentary elections, his Likud Party bloc shaved by voters asking for a focus on kitchen-table issues. Netanyahu had this answer.
PRIME MINISTER BENJAMIN NETANYAHU, Israel: The first challenge is and will continue to be preventing Iran from having nuclear weapons.
MARGARET WARNER: Israelis should have expected nothing less, says Channel 10 defense correspondent Alon Ben-David.
ALON BEN-DAVID, Channel 10: Netanyahu sees removing the Iranian threat as his lifetime mission, as a historical mission, as if history has put him in this specific time and place to relieve the Israeli people from the Iranian nuclear threat.
MARGARET WARNER: But that sense of mission drove a very public spat with President Obama last fall over when Iran's program had to be stopped before it became impervious to attack. Netanyahu famously set the red- line for Israel at the U.N.
BENJAMIN NETANYAHU: A red line should be drawn right here.
MARGARET WARNER: Mr. Obama has pledged to prevent a nuclear-armed Iran, but hasn't laid out a red line of his own.
PRESIDENT BARACK OBAMA, United States: Iran's leaders should understand that I do not have a policy of containment. I have a policy to prevent Iran from obtaining a nuclear weapon.
DEFENSE MINISTER EHUD BARAK, Israel: The relationship between our defense establishments is extraordinary.
MARGARET WARNER: The U.S. and Israel are working together with international sanctions against Iran, close intelligence cooperation and what's thought to be a covert campaign of sabotage.
But Tehran continues enriching uranium, which it insists is for peaceful power generation only. And, Monday, Tehran said it had launched a monkey into space, showing off the kind of missile prowess that could be harnessed to deliver a nuclear warhead.
DEPUTY FOREIGN MINISTER DANIEL AYALON, Israel: The Iranians are playing a cat-and-mouse game.
MARGARET WARNER: Israel's deputy foreign minister, Danny Ayalon, says Iran's enrichment pace dictates Israel's timeline.
DANIEL AYALON: If they accumulate enough uranium which is close to weapon-grade, enough uranium which enables them to detonate one nuclear device, to me, is clearly a red line.
FORMER CHIEF OF MILITARY INTELLIGENCE GEN. AMOS YADLIN, ISRAEL: The Iranian strategy is very sophisticated. And it is not to reach a bomb as fast as possible. It's reach a bomb as safe as possible.
MARGARET WARNER: Retired Air Force General Amos Yadlin, former chief of military intelligence, thinks Iran is carefully laying the groundwork for a dash to a nuclear weapon.
AMOS YADLIN: They are moving forward in a pace that will not induce a reaction from the outside and develop a very redundant program, overt, covert, under the envelope of legitimacy.
MARGARET WARNER: How serious a threat is it to Israel?
AMOS YADLIN: I consider it as the only existential threat to Israel, if you combine a very radical regime that's called in the open to the destruction and humiliation, wipe off the map of the state of Israel.
MARGARET WARNER: That's the argument embraced by Netanyahu, but disputed by others in Israel, with its own unacknowledged nuclear capability.
EFRAIM HALEVY, Former Mossad Director: I believe there is no existential threat to Israel of any kind. Israel is indestructible, in my view. We have offensive capabilities. We have defensive capabilities.
MARGARET WARNER: Efraim Halevy, who directed Israel's intelligence service, Mossad, thinks Netanyahu's hot rhetoric is off the mark.
EFRAIM HALEVY: By saying that he or she is an existential threat, you're almost inviting your enemy to try it out.
MARGARET WARNER: Others are less diplomatic.
RONNY EDRY, Israel Loves Iran Campaign: This is bull (EXPLETIVE DELETED) to me. This is just how Bibi is staying on his turf. He's selling us this idea of Iran becoming, you know, crazy, and deciding to throw a bomb on us.
MARGARET WARNER: Graphic designers Ronny Edry and Michal Tamir, husband and wife, started an online campaign last year to counter talk of war with a simple message: Israel loves Iran.
It began with a Facebook page and a YouTube video message to the Iranian people.
RONNY EDRY: For there to be a war between us, first, we must be afraid one of each other. We must hate. I'm not afraid of you. I don't hate you. I don't even know you. No Iranian ever did me no harm. I never even met an Iranian, just one in a Paris museum. Nice dude.
MARGARET WARNER: The response from Iranians poured in.
MICHAL TAMIR, Israel Loves Iran Campaign: People from Iran took a picture of themselves and did their own writing: The Israeli people, we don't hate you.
I don't even have the words to express how moving it was. I think it's an act of desperation from people to people, because the governments or prime ministers here in the Middle East, the communication is always so aggressive and so hateful.
MARGARET WARNER: Their effort blossomed online, in demonstrations and on Tel Aviv buses emblazoned with their message. But their person-to-person campaign doesn't address what some here see as Israel's dilemma: If Iran's leaders won't agree to halt enrichment and the United States doesn't act, should Israel strike on its own?
The reason it might? As Iran expands its program and drives it underground, Israel's timeline to attack is much shorter than Washington's.
AMOS YADLIN: We do have a very good air force, but your air force has more capabilities that we are not possessing. Take, for example, B-2 bomber. We have only fighters.
MARGARET WARNER: General Yadlin should know. He flew a fighter bomber in the daring 1981 mission to destroy Saddam Hussein's nuclear reactor in Iraq, a strike Washington tried to dissuade.
AMOS YADLIN: You know, the Americans can wait until they see the Iranians to really breaking out. For the Israelis, it will be too late.
MARGARET WARNER: Yet, many in Israel's military and intelligence establishment, even Yadlin, are cautioning Netanyahu not to rush ahead of the U.S. this time, at least not yet.
ALON BEN-DAVID: The vast majority of the military and intelligence people do not believe that a military strike today will be effective enough.
Look at the way that the Iranians have scattered their nuclear program. Let's assume that Israel is capable of identifying the weakest points in the Iranian nuclear program. They act against the Iranian capabilities. They don't change the Iranian motivations.
MARGARET WARNER: Halevy still thinks Iran can be persuaded to freeze its enrichment by sanctions, covert sabotage and the threat of force.
EFRAIM HALEVY: They are not demonic, and they are not messianic. They are very, very cool calculators when it comes to their direct interests. When you have the shotgun right next to your temples, sometimes, clarity emerges.
MARGARET WARNER: So, in this case, what would be the shotgun?
EFRAIM HALEVY: If they don't make a deal, there is a serious possibility that the United States and/or Israel would start a series of military activities which would be designed to neutralize Iran's capabilities.
MARGARET WARNER: But this very public talk of military action alarms many Israelis. We met Ziv Tal on Ben Yehuda Street in Jerusalem.
ZIV TAL, Israel: I am not pleased with the way Netanyahu is dealing with this, putting everything out front, instead of behind closed doors, and solving it in the way we used to solve it, in a more quiet way.
MARGARET WARNER: And Facebook campaigner Edry bemoans the state of mind that makes many Israelis receptive to Netanyahu's arguments.
RONNY EDRY: Here in Israel, we are addicted to fear and we are addicted to new enemies. We see the Arabs, the Iranians, the world out there, everybody want to kill us.
MARGARET WARNER: That sentiment is not surprising, Halevy says, given Israelis' common history, but now it's time for the nation to feel and act more confident.
EFRAIM HALEVY: This syndrome of we're not yet safe, we're not yet safe, we're not yet safe, we're not yet safe, if we are a strong force in the Middle East, I think the time has come for us to talk like a force and to operate like a force and to think like a force. That's more difficult.
MARGARET WARNER: If any country uses force against Iran's sites, Israel expects to bear the brunt of retaliation. So it's getting prepared, expanding its defensive assets, like anti-missile batteries against short-and medium-range attack.
Here is another line of defense. Originally built as a parking garage, it is now a four-story underground emergency hospital bunker. In case of an attack, conventional or unconventional, on Tel Aviv, this bed and hundreds like it would be wheeled down here, along with patients and staff.
Dr. Gabriel Barbash is director of the Sourasky Medical Center and its new underground operation.
DR. GABRIEL BARBASH, Sourasky Medical Center: Now this facility can operate on its own after it's sealed.
MARGARET WARNER: You mean entirely on its own?
GABRIEL BARBASH: Without communication with the outside world for seven days.
MARGARET WARNER: Barbash and his staff conduct drills, and the facility is pre-fitted for dialysis, surgery, trauma, all cleaned by a massive air filtration system.
GABRIEL BARBASH: The company that manufactures these filters has been established operated, and run by Christian Germans ...
MARGARET WARNER: Really?
GABRIEL BARBASH: ... that came into Israel to pay for what was done by Germany 60 years ago.
MARGARET WARNER: Do you think you will have to use this?
GABRIEL BARBASH: Yes.
We have two Iranian subsidiaries, one in the north of Israel, one in the south of Israel. Both are equipped with missiles that can reach Tel Aviv. They are aimed at Tel Aviv. So I have no doubt in my mind that this facility is going to be used.
MARGARET WARNER: As awful as retaliation could be, in the cafes of Jerusalem, we found wide agreement that the prospect of a nuclear Iran is much worse.
PNINA ENMOR, Israel: It must be the last solution, but if we have to do it, we have to do it.
DANIEL AYALON: The debate wasn't whether we should or not, but it was about the timing. And I believe that there is a unanimous understanding in Israel that, if the sword, so to speak, is on our throat, we have to act. And we will not let this sword cut the throat.
MARGARET WARNER: The two leaders will pick up that debate when Mr. Netanyahu visits Washington in March, as Israelis ponder the prospect of another tense year ahead.
JUDY WOODRUFF: Margaret's next story examines the growing divide between Israelis and Palestinians nearly 20 years after the Oslo peace accords.
And you can continue to find a link to all of our reporting from Israel, Gaza, and the West Bank on our website.