Israel's military chief said he does not believe Iran will decide to build an atomic bomb and called its leaders "very rational" - comments that clashed with Prime Minister Benjamin Netanyahu's assessment.
Lieutenant-General Benny Gantz's remarks, in an interview published on Wednesday in the left-wing Haaretz newspaper, drew little attention in Israel on its annual remembrance day for fallen soldiers, when political discourse is suspended.
But they will add fuel to an internal debate on the prospects of Iran weaponising its uranium enrichment program and the wisdom and risks of any Israeli military strike to try to prevent Tehran from becoming a nuclear power.
"Iran is moving step-by-step towards a point where it will be able to decide if it wants to make a nuclear bomb. It has not decided yet whether to go the extra mile," Gantz said.
But, he said, Iranian Supreme Leader Ayatollah Ali Khamenei could opt to produce nuclear weapons should be believe that Iran would not face reprisal.
"In my opinion, he will be making a huge mistake if he does that and I don't think he will want to go the extra mile," Gantz said.
"I think the Iranian leadership is comprised of very rational people. But I agree that such a capability in the hands of Islamic fundamentalists, who at some moments may make different calculations, is a dangerous thing."
Israel, believed to have the Middle East's only nuclear arsenal, has not ruled out military action against Iran should economic sanctions fail to curb its nuclear programme, saying all options were on the table.
Last week, in a speech during Israel's Holocaust remembrance day, Netanyahu said: "Today, the regime in Iran openly calls and determinedly works for our destruction. And it is feverishly working to develop atomic weapons to achieve that goal."
Tehran denies seeking the bomb, saying it is enriching uranium only for peaceful energy purposes and that its nuclear programme is a threat to no one.
Speaking on CNN on Tuesday, Netanyahu said he would not want to bet "the security of the world on Iran's rational behaviour." A "militant Islamic regime", he said, "can put their ideology before their survival."
The portrayal of Iran as irrational - willing to attack Israel with a nuclear weapon even if it means the destruction of the Islamic Republic in retaliatory strikes - could bolster a case for pre-emptive bombing to take out its atomic facilities.
Netanyahu had already been stung at home by his former spymaster, Meir Dagan, who said that such an Israeli strike on Iran would be a "ridiculous" idea.
Shannon Kile, a nuclear proliferation expert at the Stockholm International Peace Research Institute, said Gantz's description of Iranian leaders as rational was "quite an interesting turnabout."
"Hopefully, it is going to reduce the incentives for any sort of pre-emptive or preventive military action, at least for the time being," Kile said.
The United States has also not ruled out military action as a last resort. But many allies of Washington, and even some senior U.S. officials, fear such an attack could ignite a broader war and only temporarily halt Iran's nuclear advances.
Gantz's assessment appeared to be in step with the view of the top U.S. military officer, General Martin Dempsey. He said in a CNN interview in February he believed Iran was a "rational actor" and it would be premature to take military action against it.
Israeli political sources said at the time that the remarks by Dempsey - who also suggested Israel's armed forces could not deliver lasting damage to Iranian nuclear sites - had angered Netanyahu.
A diplomat who tracks Iran carefully said Gantz's comments might aim to tilt Israeli opinion away from a strike. "I would see it as push-back or maybe something preventive," he said, saying the assessment "flies in the face" of Netanyahu's views.
"What he said ... (is) consistent with the views of the U.S. military leadership, the U.S. intelligence community," said Carnegie Endowment for International Peace analyst George Perkovich. "What's interesting is why he said it out loud."
Israeli Defense Minister Ehud Barak raised international concern about a possible Israeli strike several months ago when he spoke about time running out for effective Israeli military action against Iranian nuclear sites buried deep underground.
Netanyahu, while noting that Iran has made no apparent decision to begin constructing a bomb, has voiced impatience with the pace of nuclear talks that began this month between Tehran and six world powers, the first such negotiations in more than a year.
"Either Iran takes its nuclear programme to a civilian footing only, or the world, perhaps us too, will have to do something. We're closer to the end of the discussions than the middle," Gantz said.
However, he also said international pressure on Iran "is beginning to bear fruit, both on the diplomatic level and on the economic sanctions level."
Netanyahu said on CNN the sanctions were "certainly taking a bite out of the Iranian economy but so far they haven't rolled back the Iranian programme or even stopped it by one iota.
"Unfortunately, that's not achieved by talks in which Iran has one goal, to stall, delay, run out the clock; that's basically what they're doing."
Gantz, a former paratrooper who has served as Israel's military attache in Washington, was asked in the Haaretz interview what impact his view would have on government decision-making on Iran.
"Whatever weight the government decides to ascribe it," he said.
"I say my opinion according to my own professional truth and my strategic analysis. I will say it sharply: I do not forget my professional ethics. The government will decide after it hears the professional echelon and the army will carry out, in a faithful and determined manner, any decision that is made."
Kile said he was surprised Gantz had spoken out, "because normally the Israeli military leadership on the nuclear issue has been quite subdued," with former intelligence officials "coming out and trying to cool ... the possible Israeli impetus towards military action."
Gantz took over as chief of staff a year ago but has been less outspoken on strategic issues than his predecessor, Gabi Ashkenazi. He was not the first choice for the job. The preferred candidate, Yoav Gallant, had to bow out because of a property scandal.
In at least one turning point in Israeli history, the government chose to ignore a strong warning from the military's top general about the intentions of a longtime adversary.
In 1977, then-chief of staff Mordechai Gur famously cautioned the Cabinet that Egyptian President Anwar Sadat's offer to visit Jerusalem could be a smokescreen for war preparations. Sadat's trip led to a peace treaty in 1979.
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