Red, Red Lines

In an April 18 speech commemorating Holocaust Remembrance Day, Israeli Prime Minister Benjamin Netanyahu painted a stark picture of the Iranian nuclear threat and made clear that Israel might soon have to take military action to address it:

"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.… Seventy years ago the Jewish people did not have the national capacity to summon the nations, nor the military might to defend itself. But today things are different.… Iran must be stopped from obtaining nuclear weapons. It is the duty of the whole world, but above and beyond, it is our duty."

As Iran's nuclear progress continues, the risk of an Israeli preventive strike grows. Given ongoing talks between Iran and the permanent members of the U.N. Security Council plus Germany (the so-called P5+1), an Israeli attack may not be imminent. But after inconclusive negotiations in Istanbul in April and Baghdad in May, we can expect the drums of war to beat even louder in Jerusalem if the third round of talks, scheduled to begin in Moscow on June 18, fails to produce results.

As we argue in a new report published by the Center for a New American Security, some of the potential dangers to Israel from a nuclear-armed Iran have been exaggerated. For example, despite the abhorrent threats by some Iranian leaders to "wipe Israel off the map," the actual behavior of the Islamic Republic over the past three decades indicates that the regime is not suicidal and is sufficiently rational for the basic logic of nuclear deterrence to hold. Iran is therefore unlikely to deliberately use nuclear weapons against Israel or enable a terrorist group to do so.

At the same time, a nuclear-armed Iran would be a much more dangerous adversary. Believing that its nuclear deterrent immunized it against retaliation, the Iranian regime would probably increase lethal support to proxies such as Hezbollah and Hamas and commit more brazen acts of terrorism abroad. The already-tense Israeli-Iranian rivalry would become more crisis-prone, and these crises would entail some inherent risk of inadvertent nuclear war.

Preventing Iran from achieving nuclear weapons should therefore remain an urgent priority. Rushing into preventive war, however, would risk making the threat worse. Until Iran appears poised to weaponize its nuclear capability, the emphasis should remain on using economic pressure and diplomacy to convince the Iranians to change course. All options, including preventive military action, should remain on the table. But force should be seen as a last resort; it should be contemplated only by the United States, and it should be employed only under stringent conditions.

In recent weeks, Israel's leadership has been less vocal about the possibility of a military strike on Iran. But this may be the calm before the storm.

On June 1, U.S. Secretary of State Hillary Clinton said, "We will know by the next meeting in Moscow in a few weeks whether Iran is prepared" to take "concrete actions" to address international concerns over its nuclear program. The P5+1 would like Iran to stop enriching uranium up to 19.75 percent, ship its current 19.75 percent stockpile out of the country, halt activities at the deeply buried Fordow enrichment facility, and expand International Atomic Energy Agency (IAEA) access to Iranian facilities in exchange for technical assistance and very minor sanctions abatement. So far, the Iranians have been unwilling to accept the deal, and they seem to expect much larger U.S. and European concessions on impending oil sanctions in exchange for cooperation. This sets the stage for high drama in Moscow.

Nothing that happens in Moscow, however, is likely to satisfy Israeli leaders. Netanyahu has been dismissive of the talks so far, saying that nothing short of Iran halting all uranium enrichment, getting rid of its entire stockpile of enriched uranium, and eliminating the means to produce more would satisfy him. Netanyahu has set the bar so high that there is no way for diplomats to clear it in Moscow. Meanwhile, Israeli Defense Minister Ehud Barak has suggested that expanded Iranian cooperation with the IAEA would not be sufficient to head off a possible Israeli strike.

Netanyahu and Barak have come under withering criticism from former Israeli intelligence officials who argue that an attack would be counterproductive. Reportedly, the current chief of staff of the Israel Defense Forces, Lt. Gen. Benny Gantz, and the current Mossad chief, Tamir Pardo, alsooppose a strike at this time. But Netanyahu and Barak are the ultimate decision-makers, and if they decide to attack, other policymakers will fall in line behind them (a point we heard repeatedly during recent interviews in Israel). What's more, Netanyahu's broad-based unity government gives him considerable room for maneuver.

The potential costs of an attack would be high. Iran would likely retaliate, using ballistic missiles, proxies, and terrorists to attack Israeli (and perhaps U.S.) targets, possibly leading to a wider war in the Levant. Attacks by Iranian-backed Shiite militants against U.S. diplomats in Iraq, or a surge in lethal assistance to insurgents fighting NATO troops in Afghanistan, could escalate U.S.-Iranian tensions. Miscalculation and confrontation with the U.S. Navy in the Persian Gulf or the Strait of Hormuz could send oil prices skyrocketing. And even in the absence of such escalation, a preventive military strike could rattle markets and push oil prices higher at a fragile time for the global economy.

By contrast, the potential benefits of an attack are uncertain. Iran's nuclear program is advanced, dispersed, redundant, and hardened. A military strike could damage key facilities, but it would not reverse Iran's accumulated nuclear knowledge or its ability to eventually build new centrifuges. An attack might therefore only delay the program for a short period. Moreover, it would risk rallying domestic Iranian opinion, which is currently divided, around weaponization, providing hard-line voices inside and outside the regime with a powerful argument in favor of acquiring a nuclear deterrent. Iran would most likely move rapidly to reconstitute its nuclear program and kick out IAEA inspectors, making it more difficult to detect rebuilding.

Given the threat posed by Iran's nuclear ambitions, the option of using force should remain on the table. But the high risks and uncertain rewards mean it should be employed only if: (1) all nonmilitary options have been exhausted; (2) Iran has made a clear move toward weaponization; (3) there is a reasonable expectation that a strike would significantly set back Iran's program; and (4) a sufficiently large international coalition is available first to help manage the destabilizing consequences of the strike and then to contain Iran and hinder it from rebuilding its nuclear program.

Today, a unilateral Israeli strike would not satisfy any of these criteria.

Iran has made considerable progress in recent years, but it is not on the brink of getting nuclear weapons. Considering the four months it would currently take for Iran to produce sufficient weapons-grade uranium for a single bomb and the other weaponization hurdles it must overcome, the Institute for Science and International Security estimates that it would take Iran about a year to produce a crude testable nuclear device. Fashioning a weapon sophisticated enough to fit on the tip of a missile would likely take several years.

Importantly, none of these timelines start until the supreme leader says "go," and U.S. and Israeli officials believe Ayatollah Ali Khamenei has not yet decided to do so. As Lt. Gen. Gantz recently toldHaaretz, 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 to go the extra mile." What's more, Khamenei is not likely to make that decision anytime soon since it would require Iran to begin enriching to weapons-grade level at either the Natanz or Fordow enrichment plants -- both declared facilities under the watchful eye of IAEA inspectors. Because a break-out attempt would likely be detected, potentially triggering a military response from the international community, Khamenei is unlikely to act until Iran has the capability either to build several devices so quickly that the international community cannot respond or to build them in secret -- which could be years from now.

It is also conceivable that the supreme leader would be satisfied with a capability that stopped just short of actual weaponization. Khameni might conclude that acquiring the ability to rapidly produce nuclear weapons -- a "threshold" capability -- would provide Iran with a sufficient deterrent, while lowering the risk of deeper international isolation, an expensive regional arms race, and a potential U.S. or Israeli military strike that might result from explicitly violating the Nuclear Non-Proliferation Treaty (NPT). A threshold capability would also allow Khamenei to retain his oft-stated position that acquiring, stockpiling, or using nuclear weapons would be a "grave sin" against Islam, a religious edict (fatwa) that senior Iranian officials describe as a "binding commitment."

The only sustainable solution is for the Iranians to choose to step back from the nuclear precipice themselves -- or be compelled to do so. Whether they will take this step remains to be seen, but unprecedented financial and energy sanctions -- the latter of which are only beginning to kick in -- appear to finally be affecting their calculations, as evidenced by the regime's willingness to return to negotiations.

Diplomacy should aim to roll back Iran's nuclear progress as far as possible, but we must avoid letting the perfect become the enemy of the possible. Unfortunately, this is precisely what some in Jerusalem and Washington are doing by laying out counterproductive red lines.

To preclude Iran from achieving a nuclear weapons "capability" -- an undefined technological status that, according to U.S. intelligence officials, Iran may already have achieved -- some Israeli officials, members of Congress, and outside experts have called on the Obama administration to reject any deal that would permit future domestic enrichment, however limited and regardless of the associated safeguards. This position is at odds with statements last year by Secretary Clinton, recent comments by other Obama administration officials, and the past position of the P5+1, which implied that continued enrichment to low levels might be acceptable if Iran addresses other concerns about its program. This red line also reduces almost to zero thechances of a final agreement acceptable to Iranian leaders, who have banked their domestic legitimacy on asserting its inalienable nuclear "rights" in the face of international pressure.

The most important goal should be to prevent Iran from developing actual nuclear weapons. If Iran verifiably ends its weaponization work, operates strictly and transparently within the confines of the NPT, and agrees to sufficient technical safeguards and intrusive inspections, then a deal allowing limited domestic enrichment should be acceptable. Even reaching such an agreement will be difficult, but there is still time to let the process play out.

Time, of course, is the one thing Israeli leaders say they don't have. Ehud Barak frequently warns that Iran's program might soon be so hardened and redundant that it will enter a "zone of immunity" from Israeli attack, creating a now-or-never impetus to strike. However, despite its formidable military capabilities, Israel probably already lacks the capability to significantly set back the Iranian program. Indeed, senior U.S. defense officials have repeatedly stated that an Israeli attack would only delay Iran's nuclear program at most by 1 to 3 years. Echoing these sentiments, Israeli President Shimon Peres recently said: "Some people say it [an Israeli strike] will make Iran powerless for two to three years. That's not good enough."

Given the Israeli perception of the Iranian nuclear threat, even a minor delay in Iran's program might seem like an improvement over the status quo. But an Israeli strike would likely prompt the Iranian regime to rapidly rebuild its nuclear program, just as Saddam Hussein redoubled his efforts after Israel's 1981 preventive strike on the Osirak nuclear reactor. Indeed, in the aftermath of an Israeli strike, Iran would have incentives to reconstitute its program in the very facilities that Barak and other Israeli leaders worry are invulnerable from attack, and probably in new clandestine facilities as well. And although it is currently conceivable that the Iranian regime will stop short of weaponization, a strike would settle any internal debate in favor of those arguing for an unambiguous nuclear deterrent.

Finally, unless there is some prospect of maintaining sufficient international agreement in the aftermath of an attack to thwart Tehran's rebuilding efforts, an Israeli strike would, at best, have limited effects and, at worst, increase the threat. A unilateral Israeli attack would most likely shatter the very international consensus needed to support sanctions, diplomatic isolation, potential re-strikes on nuclear facilities, and other enforcement measures designed to block Iran's reconstitution efforts in the years following the strike.

For all those reasons, even though the military option should remain on the table, Israel should not be the one to use it. Only the United States, with its much larger bunker-busting munitions and the ability to prosecute a sustained military campaign, would be capable of meaningfully delayingIran's program. And only Washington, having exhausted all other options and acting in the face of compelling evidence that Iran was determined to acquire a bomb, would have any hope of holding together the type of coalition required to prevent Iran from emerging from an attack more dangerous than ever.

U.S. and Israeli officials often describe an Iranian nuclear weapon as "unacceptable." But as they seek to prevent the unacceptable, they need to do so in ways that avoid making the threat inevitable.