Discussions surrounding Iran’s alleged nuclear weapons ambitions frequently cross the line into unsubstantiated assertions about Iran’s nuclear intentions and capabilities. But in an interview with Haaretz, Israel’s chief military officer offered a more nuanced view of Iran’s nuclear program.

Lieutenant General Benny Gantz told Haaretz that Iran has not yet made critical decisions:

[Iran] is going step by step to the place where it will be able to decide whether to manufacture a nuclear bomb. It hasn’t yet decided whether to go the extra mile.

Gantz also emphasized that Iran is a rational actor, a departure from hawks who claim that Iran’s leadership is irrational:

[The acquisition of a nuclear bomb] will happen if [Iran's Supreme Leader Ayatollah Ali] Khamenei judges that he is invulnerable to a response. I believe he would be making an enormous mistake, and I don’t think he will want to go the extra mile. I think the Iranian leadership is composed of very rational people. But I agree that such a capability, in the hands of Islamic fundamentalists who at particular moments could make different calculations, is dangerous.

The Israeli military chief said that all options — including the military one — remain on the table for Israel and that “This is a critical year, but not necessarily ‘go, no-go.’” And he reported that diplomatic presure and economic sanctions are begining to bear fruit.

Gantz’s comments contrast with Israel Prime Minister Benjamin Netanyahu’s hawkish rhetoric on Iran. In an interview with CNN’s Erin Burnett last night, Netanyahu questioned Iran’s rationality:

I don’t think you want to bet the peace in the Middle East and the security of the world on Iran’s rational behavior.

A potential Iranian nuclear weapon is widely considered a threat to both the security of the U.S. and its allies in the region, and the nuclear non-proliferation regime. While hawkish rhetoric towards Iran is becoming a normal occurrence in the political discourses in both Israel and the U.S., neither IAEA, Israeli nor U.S. intelligence estimates conclude that Iran has decided to build a nuclear weapon. The Obama administration has vowed to keep “all options on the table” to deal with the possibility of Iran pursuing a nuclear weapon but the efficacy and consequences of such a military strike continue to raise serious questions.

Israeli Defense Minister Ehud Barak appeared on CNN yesterday to be interviewed by anchor Christiane Amanpour. In a sometimes contentious interview, Amanpour focused mostly on the Iranian nuclear program. Despite agreement that a potential nuclear armed Iran would constitute a threat, a slight rift opened up last week between the U.S. and Israeli administrations over the first new round of talks between Iran and the permanent members of the U.N. Security Council and Germany.

Amanpour dove into Iran issues and commented on Barak’s repeated references to Iran’s “military nuclear program.” Amanpour cited reports about American intelligence estimates which — along with Israeli and International Atomic Energy Agency (IAEA) estimates — doesn’t conclude that Iran has decided on building a weapon. “You’re obviously very concerned, and so are many, should Iran get a nuclear capability that’s military. As I said, the U.S. does not believe any such decision has been made,” she said. Barak shot back: “No, no, no. The — I want to correct you.” He didn’t, however, contradict what she said, but rather added to it his own assessment:

BARAK: I’m talking to the American intelligence. I’ve talked to American leaders. There is no difference in the assessment of intelligence. It’s true that probably [Iranian Supreme Leader] Khamenei did not give an order to start building a weapon or a device.

But why he’s doing this, just because he understands that if he starts to break the IAEA and start to actually build a weapon, he might find himself faced with an American response, Israeli response or whoever, in a way that might damage him. And that’s the only reason why he did not give the order. But they’re clearly heading toward this objective.

AMANPOUR: But if that’s the case, then, then surely the pressure is working, that they’re not doing it, as you said, because the pressure is there and the threat of what you might do.

BARAK: These are quite effective sanctions. But it’s still far away from working.

Watch the video:

Barak is right to say that sanctions have not worked, as such, because Iran has yet to answer many questions from the IAEA about its past activities and allow unfettered access to sites on the IAEA’s list — both points Barak made. But Barak’s conclusion, which buttressed Amanpour’s point, is also correct: pressure is having an effect, as evinced by Iran’s willingness to come to the table and engage — albeit on what will almost certainly be a rocky path. President Obama has vowed to keep all options on the table and limits the window for successful negotiations, which his administration considers the “best and most permanent way” to end the crisis.

Barak’s comments that sanctions “are quite effective” track with those of Israel’s Ambassador to the U.N. Ron Prosor, who said earlier this month that the sanctions track is “much more effective than people think and it might change, hopefully it might change behavior patterns if we continue with it.”

A new report from the Congressional Research Service (CRS) — an organization dedicated to carrying out non-partisan investigations for Congress — laid out considerations that could affect an Israeli decision to attack Iran’s nuclear program, and the potential issues that the U.S. might have to deal with in the wake of such an event.

The CRS report’s (PDF) summary states:

By all accounts, such an attack could have considerable regional and global security, political, and economic repercussions, not least for the United States, Israel, and their bilateral relationship. It is unclear what the ultimate effect of a strike would be on the likelihood of Iran acquiring nuclear weapons.

A potential Iranian nuclear weapon is widely considered a threat to both the security of the U.S. and its allies in the region, and the nuclear non-proliferation regime — though U.S. intelligence has not concluded that Iran has made a decision to pursue a weapon. The Obama administration vows to keep “all options on the table” to deal with the possibility, but the efficacy and consequences of a strike raise serious questions, leading the U.S. to pursue, for the meantime, a pressure track aimed at a negotiated resolution of the Iranian nuclear crisis.

An Israeli decision to carry out air strikes could hinge on the potential it sees for inflicting long-term damage on Iran’s nuclear program. One aspect of that potential — and one that gives rise to uncertainty — rests on Iran’s ability to reconstitute aspects of its program. Iran, over the years, dispersed it’s program into different locations, some shrouded in mystery.

The report honed in on Iran’s ability to preserve nuclear knowledge and the capability to rebuild its program through its opaque “workshops” for building centrifuges. Bloomberg News noted, “The possibility of dispersed facilities complicates any assessment of a potential raid’s success.” The CRS report went on to cite a former U.S. official with direct knowledge on the issue stating:

Iran’s centrifuge production is widely distributed and that the number of workshops has probably multiplied ‘many times’ since 2005 because of an increase in Iranian contractors and subcontractors working on the program.

Iran withdrew from the rigorous inspection standards of the Nuclear Non-Proliferation Treaty’s Additional Protocols in 2006. While the U.N.’s International Atomic Energy Agency (IAEA) maintains access to Iranian enrichment sites, activities related to the construction of those centrifuges — before they get moved into enrichment sites — remain largely in the dark since 2006.

CRS estimated that Iran could largely rebuild its centrifuge construction “workshops” within six months of an attack. The Arms Control Association’s Peter Crail told Bloomberg news that a military strike would likely cause Iran to kick out IAEA inspectors, allowing the Islamic Republic to construct an entirely new enrichment facility dedicated to weapons-grade uranium away from international eyes. Crail told Bloomberg:

At some point they are going to reconstitute the program. It’s really just a question of can they do it within a year or two or is it going to take them a little bit longer.

The IAEA’s latest reports on Iran’s nuclear program and congressional testimony from Director of National Intelligence James Clapper have all come to the same conclusion. While Iran’s leadership is “keeping themselves in a position to [decide to make a nuclear weapon],” as Clapper testified, there is no strong evidence that Iran has decided to restart its nuclear weapons program.

A special report today by Reuters provides new evidence to bolster the U.S. and IAEA’s assessments that Iran hasn’t yet decided to pursue a nuclear weapon and has not reconstituted a clandestine nuclear weapons program.

Most strikingly, Reuters has learned of an intercepted phone call in 2006 or 2007 in which Mohsen Fakhrizadeh, a leading figure in Iran’s nuclear program, complains that Iran’s nuclear weapons program has been stopped. The phone call helped form the backbone for a controversial 2007 National Intelligence Estimate (NIE) in which American spy agencies expressed “high confidence” that Iran had halted its nuclear program in 2003.

The Reuters report finds that intelligence officials have a high-degree of confidence that Iran has no secret uranium enrichment sites and an Iranian decision to enrich uranium to weapons grade levels will be detected by U.S. intelligence and IAEA monitoring mechanisms.

“I think they are years away from having a nuclear weapon,” a U.S. administration official told Reuters.

Intelligence officials tell Reuters that they were aware for “years” of the construction of the secret Fordow uranium enrichment site and that “They had a deep understanding of the facility, which allowed them to blow the whistle on Tehran with confidence,” a U.S. official said. Iran claimed when the facility was exposed that they were not responsible for declaring it until the facility was fitted for and began nuclear work.

“We are very confident that there is no secret site now,” a U.S. administration official said, but admitted that Iran may attempt to construct another covert plant in the future.

Experts speaking to Reuters confirmed the IAEA’s analysis that Iran’s efforts to procure nuclear-related and dual-use equipment and the country’s large cache of ballistic missiles are examples of growing capabilities that could potentially be used for nuclear weapons.

The debate over air strikes, Israel’s anxieties about a nuclear-armed Iran and election-year politics have all contributed to comparisons with the Iraq war, a war justified by inaccurate intelligence data suggesting Saddam Hussein was developing weapons of mass destruction and unsubstantiated claims of significant ties between Iraq and al Qaeda. Paul Pillar, a former top CIA analyst told Reuters:

There are lots of disturbing similarities. One has to note the differences, too. The huge difference being we don’t have an administration in office that is the one hankering for the war. This administration is not hankering for a war.

President Obama said recently that Iran with a nuclear weapon threatens the nonproliferation regime and U.S. and regional security. The Obama administration has ruled out a policy of containing a nuclear-armed Iran but has emphasized that a diplomatic solution is “the best and most permanent way” to relieve mounting tensions over Iran’s nuclear program.

Discussion of a U.S. and/or Israeli strike on Iran’s nuclear facilities is emerging as one of the foremost foreign policy issues in 2012. President Obama warned against “loose talk of war” with Iran. And former Israeli Mossad Chief Meir Dagan tells CBS’s “60 Minutes” program, in an interview to be aired on Sunday, that “An attack on Iran before you are exploring all other approaches is not the right way.”

Republican presidential hopefuls Mitt Romney and Newt Gingrich have both struck a more hawkish tone, asserting without corroboration from the IAEA and U.S. intelligence services that Iran is definitely building a nuclear weapon. But, despite the eagerness of GOP hawks to discuss military action, the Israeli public is far from convinced that a military strike will serve Israel’s long-term interests or come without a sizable cost in Israeli lives.

A new poll conducted by Tel Aviv University’s Guttman Center [PDF] finds that 62.9 percent of Israelis strongly or moderately oppose an Israeli unilateral attack on Iran. See the breakdown below:

Approximately 70 percent of Israelis believe such an attack would be ineffective in “stopping Iran’s nuclearization for a substantial time” and approximately 60 percent think that Israeli Defense Minister Ehud Barak is underestimating in his assessment that an Iranian retaliatory strike will cause about 500 Israeli casualties.

The Guttman Center’s findings fall in line with a series of recent polls on Israeli public opinion. A Haaretz poll released yesterday found that 58 percent of Israelis oppose an strike on Iran without U.S. backing. And a University of Maryland poll last month showed that only 19 percent of Israelis support an attack without U.S. backing.

The IAEA has expressed concerns about “possible military dimensions” to Iran’s nuclear program and is reportedly concerned that the Iranians may be attempting to cleanse a military site of nuclear weapons related work. Obama publicly stated that an Iranian bomb would pose a threat to the U.S. and its allies and do damage to the nuclear nonproliferation regime. Neither Israeli nor U.S. intelligence officials have asserted that Iran has yet restarted its nuclear weapons program.

The Guttman Center poll found that 64 percent of Israelis would support an attack on Iran if launched in cooperation with the U.S. while 43 percent still opposed a preemptive strike.

Today during a Oval Office press briefing with Israeli Prime Minister Benjamin Netanyahu, President Obama said the two leaders “prefer” to solve the Iranian nuclear crisis “diplomatically.” But the two men have not always seens eye-to-eye on how to confront Iran’s alleged nuclear weapons program. Netanyahu has openly rejected efforts to diplomatically deter Iran from pursuing a nuclear weapon while Obama, speaking at the AIPAC conference on Sunday, warned that “loose talk of war” is benefiting the Iranian government.

But a full page Washington Post ad taken out by the National Iranian American Council (NIAC) — and signed by eight retired, high ranking, military and intelligence officials — urges Obama to continue exploring diplomatic paths and resist the push for war with Iran. The ad reads:

Unless we or an ally is attacked, war should be the option of last resort. Our brave servicemen and women expect you to exhaust all diplomatic and peaceful options before you send them into harm’s way.

Preventing a nuclear armed Iran is rightfully your priority and red line. Fortunately, diplomacy had not been exhausted and peaceful solutions are still possible.

While Obama reiterated in his speech to AIPAC yesterday that he “will take no options off the table” in dealing with Iran’s nuclear program, GOP presidential candidates Rick Santorum, Newt Gingrich and Mitt Romney have blasted Obama as insufficiently hawkish on Iran.

In their testimony before Congress, American intelligence and military leadership consistently make the case that Iran has not yet decided to pursue a nuclear weapon and diplomacy and sanctions can still work to deter Iran from restarting its nuclear weapons program. The IAEA has repeatedly expressed concerns about possible military dimensions to Iran’s nuclear program but has not concluded that Tehran has restarted its nuclear weapons program.

Signatories of the NIAC letter — which include five retired Generals — urge Obama to “resist the pressure for a war of choice with Iran.”

Indeed, George W. Bush’s CIA director issued an even more stark warning. In January, former CIA director and NSA chief Gen. Michael Hayden told Foreign Policy’s Josh Rogin that the Bush administration had carefully examined the possibility of bombing Iran and concluded that “[attacking Iran] would guarantee that which we are trying to prevent — an Iran that will spare nothing to build a nuclear weapon.”

In the latest of its quarterly reports on the Iranian nuclear program (PDF), the U.N. nuclear watchdog said that Iran is expanding its uranium enrichment capacity and has not provided IAEA inspectors with an explanation for a significant quantity of missing nuclear material.

The report, which comes on the heels of two days of talks between International Atomic Energy Agency (IAEA) inspectors and Iranian officials, details how IAEA personnel were denied access to the Parchin military facility and failed to get answers about the role of foreign experts in Iran’s nuclear research:

The Agency is unable to provide credible assurance about the absence of undeclared nuclear materials and activities in Iran, and therefore to conclude that all nuclear material in Iran is in peaceful activities.

The new report reiterated the IAEA’s concerns — stated at length in its Novermber 2011 report — about Iranian non-compliance, particularly as it relates to possible nuclear weapons work, referring again to “serious concerns regarding possible military dimensions to Iran’s nuclear programme.”

“There’s nothing that’s really unexpected,” said Peter Crail, a nonproliferation analyst with the Arms Control Association, in an interview with ThinkProgress. The Iranians are “sort of steadily moving ahead.”

He noted that though latest generation centrifuges were reported as installed for the first time, they were in early stages of development and Iran appeared to still be tinkering with earlier generation centrifuges. “This (report) was more of a standard update of where the program is,” he said. “As expected, they are still making progress in installing things, but there’s no massive expansion or breakthrough development.”

While the IAEA again raised concerns about lack of access, expanding production, and a quantity of unaccounted for nuclear material, the report doesn’t indicate Iran is any closer to deciding on building a nuclear weapon. The absence of such an assertion is in line with reported U.S. intelligence estimates and statements by top military and intelligence officials.

Since the November report, the greatest change in Iran’s nuclear program, according to inspectors, has been the stepped up enrichment of uranium. The Natanz nuclear facility is now operating 52 cascades — each containing 170 centrifuges — up from 37 in November, and the Fordow facility is now refining Uranium to a 20% concentration with almost 700 centrifuges.

In January, Iran informed the IAEA of revisions in its intentions at the Fordow enrichment plant to include enrichment to 5 percent, in addition to the 20 percent enrichment that can be more easily upgraded to weapons-grade fissile material. “I’m not clear exactly what that means,” said ACA’s Crail. “But if Fordow isn’t dedicated only to 20 percent (enrichment), it also may suggest that they are willing to halt 20 percent because they are hedging with the facility by doing two types of production.”

The IAEA also raised concerns about 19.8 kilograms of unaccounted for uranium “related to conversion experiments carried out by Iran between 1995 and 2002.” The discrepancy in measurement amounts was previously reported, but Iran again refused to answer questions about the missing quantity. Asked in the February meetings between the IAEA and Iran, the new report said, Iran stonewalled:

Iran indicated that it no longer possessed the relevant documentation and that the personnel involved were no longer available… The discrepancy remains to be clarified.

Diplomats told the Associated Press the quantity could be enough to work on weapons. ACA’s Crail said, however, it wasn’t “nearly enough” yet to actually make a bomb, though “because it’s in uranium metal form it may be useful for carrying out warhead R&D (research and development).”

The report will likely raise tensions between Iran and the West over the former’s nuclear progress, which it insists is for peaceful purposes.

Chairman of the Joint Chiefs of Staff Gen. Martin Dempsey urged against an Israeli strike on Iran’s nuclear program, telling CNN’s Fareed Zakaria this morning that “It’s not prudent at this point to decide to attack Iran,” and such a strike would be “destabilizing and wouldn’t achieve [Israel's] long-term objectives.”

Dempsey, the highest ranking military officer in the U.S., went on to emphasize that while all options remain on the table, U.S. intelligence indicates that Iran has not yet decided to pursue a nuclear weapon:

MARTIN DEMPSEY: We also know, or believe we know, that the Iranian regime has not decided that they will embark on the [...] effort to weaponize their nuclear capability.

FAREED ZAKARIA: You think that is still unclear? [...]

DEMPSEY: It is. I believe it is unclear and on that basis I think it would be premature to exclusively decide that the time for a military option was upon us.

Watch the interview:

Dempsey’s conclusion that Iran has not yet decided to pursue a nuclear weapon reflects the consensus view of the U.S. intelligence community and the IAEA. Director of National Intelligence James Clapper told the Senate Armed Service Committee on Thursday that Iran’s leadership had not yet decided to develop a nuclear weapon but were “keeping themselves in a position to make that decision.”

The November IAEA report on Iran’s nuclear program found that while there were possible military dimensions to Iran’s nuclear program, the nuclear watchdog agency couldn’t confirm that Tehran was pursuing a nuclear weapon. The IAEA’s findings were upheld by CIA Director David Petraeus last month. Petraeus told the Senate Intelligence Committee that the IAEA report is “the authoritative document” on Iran’s nuclear program.

Indeed, a nuclear weapons possessing Iran would be destabilizing but while hawks on Capitol Hill are eager to portray Iran as a “martyr state” hellbent on acquiring nuclear weapons, senior intelligence and military officials take a very different view. “We are of the opinion that the Iranian regime is a rational actor,” said Dempsey. “And it’s for that reason that we think the current path we’re on is the most prudent path at this point.”