In "Time to Attack Iran" (January/February 2012), Matthew Kroenig takes a page out of the decade-old playbook used by advocates of the Iraq war. He portrays the threat of a nuclear-armed Iran as both grave and imminent, arguing that the United States has little choice but to attack Iran now before it is too late. Then, after offering the caveat that "attacking Iran is hardly an attractive prospect," he goes on to portray military action as preferable to other available alternatives and concludes that the United States can manage all the associated risks. Preventive war, according to Kroenig, is "the least bad option."

But the lesson of Iraq, the last preventive war launched by the United States, is that Washington should not choose war when there are still other options, and it should not base its decision to attack on best-case analyses of how it hopes the conflict will turn out. A realistic assessment of Iran's nuclear progress and how a conflict would likely unfold leads one to a conclusion that is the opposite of Kroenig's: now is not the time to attack Iran.

BAD TIMING

Kroenig argues that there is an urgent need to attack Iran's nuclear infrastructure soon, since Tehran could "produce its first nuclear weapon within six months of deciding to do so." Yet that last phrase is crucial. The International Atomic Energy Agency (IAEA) has documented Iranian efforts to achieve the capacity to develop nuclear weapons at some point, but there is no hard evidence that Supreme Leader Ayatollah Ali Khamenei has yet made the final decision to develop them.

In arguing for a six-month horizon, Kroenig also misleadingly conflates hypothetical timelines to produce weapons-grade uranium with the time actually required to construct a bomb. According to 2010 Senate testimony by James Cartwright, then vice chairman of the U.S. Joint Chiefs of Staff, and recent statements by the former heads of Israel's national intelligence and defense intelligence agencies, even if Iran could produce enough weapons-grade uranium for a bomb in six months, it would take it at least a year to produce a testable nuclear device and considerably longer to make a deliverable weapon. And David Albright, president of the Institute for Science and International Security (and the source of Kroenig's six-month estimate), recently told Agence France-Presse that there is a "low probability" that the Iranians would actually develop a bomb over the next year even if they had the capability to do so. Because there is no evidence that Iran has built additional covert enrichment plants since the Natanz and Qom sites were outed in 2002 and 2009, respectively, any near-term move by Tehran to produce weapons-grade uranium would have to rely on its declared facilities. The IAEA would thus detect such activity with sufficient time for the international community to mount a forceful response. As a result, the Iranians are unlikely to commit to building nuclear weapons until they can do so much more quickly or out of sight, which could be years off.

Kroenig is also inconsistent about the timetable for an attack. In some places, he suggests that strikes should begin now, whereas in others, he argues that the United States should attack only if Iran takes certain actions—such as expelling IAEA inspectors, beginning the enrichment of weapons-grade uranium, or installing large numbers of advanced centrifuges—any one of which would signal that it had decided to build a bomb. Kroenig is likely right that these developments—and perhaps others, such as the discovery of new covert enrichment sites—would create a decision point for the use of force. But the Iranians have not taken these steps yet, and as Kroenig acknowledges, "Washington has a very good chance" of detecting them if they do.

RIDING THE ESCALATOR

Kroenig's discussion of timing is not the only misleading part of his article; so is his contention that the United States could mitigate the "potentially devastating consequences" of a strike on Iran by carefully managing the escalation that would ensue. His picture of a clean, calibrated conflict is a mirage. Any war with Iran would be a messy and extraordinarily violent affair, with significant casualties and consequences.

According to Kroenig, Iran would not respond to a strike with its "worst forms of retaliation, such as closing the Strait of Hormuz or launching missiles at southern Europe" unless its leaders felt that the regime's "very existence was threatened." To mitigate this risk, he claims, the United States could "make clear that it is interested only in destroying Iran's nuclear program, not in overthrowing the government." But Iranian leaders have staked their domestic legitimacy on resisting inter-national pressure to halt the nuclear program, and so they would inevitably view an attack on that program as an attack on the regime itself. Decades of hostility and perceived U.S. efforts to undermine the regime would reinforce this perception. And when combined with the emphasis on anti-Americanism in the ideology of the supreme leader and his hard-line advisers, as well as their general ignorance about what drives U.S. decision-making, this perception means that there is little prospect that Iranian leaders would believe that a U.S. strike had limited aims. Assuming the worst about Washington's intentions, Tehran is likely to overreact to even a surgical strike against its nuclear facilities.

Kroenig nevertheless believes that the United States could limit the prospects for escalation by warning Iran that crossing certain "redlines" would trigger a devastating U.S. counterresponse. Ironically, Kroenig believes that a nuclear-armed Iran would be deeply irrational and prone to miscalculation yet somehow maintains that under the same leaders, Iran would make clear-eyed decisions in the immediate aftermath of a U.S. strike. But the two countries share no direct and reliable channels for communication, and the inevitable confusion brought on by a crisis would make signaling difficult and miscalculation likely.

To make matters worse, in the heat of battle, Iran would face powerful incentives to escalate. In the event of a conflict, both sides would come under significant pressure to stop the fighting due to the impact on international oil markets. Since this would limit the time the Iranians would have to reestablish deterrence, they might choose to launch a quick, all-out response, without care for redlines. Iranian fears that the United States could success-fully disrupt its command-and-control infrastructure or preemptively destroy its ballistic missile arsenal could also tempt Iran to launch as many missiles as possible early in the war. And the decentralized nature of Iran's Islamic Revolutionary Guard Corps, especially its navy, raises the prospect of unauthorized responses that could rapidly expand the fighting in the crowded waters of the Persian Gulf.

Controlling escalation would be no easier on the U.S. side. In the face of reprisals by Iranian proxies, "token missile strikes against U.S. bases and ships," or "the harassment of commercial and U.S. naval vessels," Kroenig says that Washington should turn the other cheek and constrain its own response to Iranian counter-attacks. But this is much easier said than done. Just as Iran's likely expectation of a short war might encourage it to respond disproportionately early in the crisis, so the United States would also have incentives to move swiftly to destroy Iran's conventional forces and the infrastructure of the Revolutionary Guard Corps. And if the United States failed to do so, proxy attacks against U.S. civilian personnel in Lebanon or Iraq, the transfer of lethal rocket and portable air defense systems to Taliban fighters in Afghanistan, or missile strikes against U.S. facilities in the Gulf could cause significant U.S. casualties, creating irresistible political pressure in Washington to respond. Add to this the normal fog of war and the lack of reliable communications between the United States and Iran, and Washington would have a hard time determining whether Tehran's initial response to a strike was a one-off event or the prelude to a wider campaign. If it were the latter, a passive U.S. approach might motivate Iran to launch even more dangerous attacks—and this is a risk Washington may choose not to take. The sum total of these dynamics would make staying within Kroenig's proscribed limits exceedingly difficult.

Even if Iran did not escalate, purely defensive moves that would threaten U.S. personnel or international shipping in the Strait of Hormuz—the maritime chokepoint through which nearly 20 percent of the world's traded oil passes—would also create powerful incentives for Washington to preemptively target Iran's military. Of particular concern would be Iran's "anti-access/area-denial" capabilities, which are designed to prevent advanced navies from operating in the shallow waters of the Persian Gulf. These systems integrate coastal air defenses, shore-based long-range artillery and antiship cruise missiles, Kilo-class and midget submarines, remote-controlled boats and unmanned kamikaze aerial vehicles, and more than 1,000 small attack craft equipped with machine guns, multiple-launch rockets, antiship missiles, torpedoes, and rapid-mine-laying capabilities. The entire 120-mile-long strait sits along the Iranian coastline, within short reach of these systems. In the midst of a conflict, the threat to U.S. forces and the global economy posed by Iran's activating its air defenses, dispersing its missiles or naval forces, or moving its mines out of storage would be too great for the United States to ignore; the logic of preemption would compel Washington to escalate.

Some analysts, including Afshin Molavi and Michael Singh, believe that the Iranians are unlikely to attempt to close the strait due to the damage it would inflict on their own economy. But Tehran's saber rattling has already intensified in response to the prospect of Western sanctions on its oil industry. In the immediate aftermath of a U.S. strike on Iran's nuclear program, Iranian leaders might perceive that holding the strait at risk would encourage international pressure on Washington to end the fighting, possibly deterring U.S. escalation. In reality, it would more likely have the opposite effect, encouraging aggressive U.S. efforts to protect commercial shipping. The U.S. Navy is capable of keeping the strait open, but the mere threat of closure could send oil prices soaring, dealing a heavy blow to the fragile global economy. The measures that Kroenig advocates to mitigate this threat, such as opening up the U.S. Strategic Petroleum Reserve and urging Saudi Arabia to boost oil production, would be unlikely to suffice, especially since most Saudi crude passes through the strait.

Ultimately, if the United States and Iran go to war, there is no doubt that Washington will win in the narrow operational sense. Indeed, with the impressive array of U.S. naval and air forces already deployed in the Gulf, the United States could probably knock Iran's military capabilities back 20 years in a matter of weeks. But a U.S.-Iranian conflict would not be the clinical, tightly controlled, limited encounter that Kroenig predicts.

SPILLOVER

Keeping other states in the region out of the fight would also prove more difficult than Kroenig suggests. Iran would presume Israeli complicity in a U.S. raid and would seek to drag Israel into the conflict in order to undermine potential support for the U.S. war effort among key Arab regimes. And although it is true, as Kroenig notes, that Israel remained on the sidelines during the 1990-91 Gulf War, the threat posed by Iran's missiles and proxies today is considerably greater than that posed by Iraq two decades ago. If Iranian-allied Hezbollah responded to the fighting by firing rockets at Israeli cities, Israel could launch an all-out war against Lebanon. Syrian President Bashar al-Assad might also try to use the moment to divert attention from the uprising in his country, launching his own assault on the Jewish state. Either scenario, or their combination, could lead to a wider war in the Levant.

Even in the Gulf, where U.S. partners are sometimes portrayed as passive, Iranian retaliation might draw Saudi Arabia and the United Arab Emirates into the conflict. The Saudis have taken a much more confrontational posture toward Iran in the past year, and Riyadh is unlikely to tolerate Iranian attacks against critical energy infrastructure. For its part, the UAE, the most hawkish state in the Gulf, might respond to missiles raining down on U.S. forces at its Al Dhafra Air Base by attempting to seize Abu Musa, Greater Tunb, and Lesser Tunb, three disputed Gulf islands currently occupied by Iran.

A strike could also set off wider destabilizing effects. Although Kroenig is right that some Arab leaders would privately applaud a U.S. strike, many on the Arab street would reject it. Both Islamist extremists and embattled elites could use this opportunity to transform the Arab Spring's populist antiregime narrative into a decidedly anti-American one. This would rebound to Iran's advantage just at the moment when political developments in the region, chief among them the resurgence of nationalism in the Arab world and the upheaval in Syria, are significantly undermining Iran's influence. A U.S. strike could easily shift regional sympathies back in Tehran's favor by allowing Iran to play the victim and, through its retaliation, resuscitate its status as the champion of the region's anti-Western resistance.

THE COST OF BUYING TIME

Even if a U.S. strike went as well as Kroenig predicts, there is little guarantee that it would produce lasting results. Senior U.S. defense officials have repeatedly stated that an attack on Iran's nuclear facilities would stall Tehran's progress for only a few years. Kroenig argues that such a delay could become permanent. "Those countries whose nuclear facilities have been attacked -- most recently Iraq and Syria," he writes, "have proved unwilling or unable to restart their programs." In the case of Iraq, however, Saddam Hussein restarted his clandestine nuclear weapons program after the 1981 Israeli attack on the Osirak nuclear reactor, and it required the Gulf War and another decade of sanctions and intrusive inspections to eliminate it. Iran's program is also more advanced and dispersed than were Iraq's and Syria's, meaning it would be easier to reconstitute. A U.S. strike would damage key Iranian facilities, but it would do nothing to reverse the nuclear knowledge Iran has accumulated or its ability to eventually build new centrifuges.

A U.S. attack would also likely rally domestic Iranian support around nuclear hard-liners, increasing the odds that Iran would emerge from a strike even more committed to building a bomb. Kroenig downplays the "rally round the flag" risks by noting that hard-liners are already firmly in power and suggesting that an attack might produce increased internal criticism of the regime. But the nuclear program remains an enormous source of national pride for the majority of Iranians. To the extent that there is internal dissent over the program, it is a discussion about whether the country should acquire nuclear weapons or simply pursue civilian nuclear technology. By demonstrating the vulnerability of a non-nuclear-armed Iran, a U.S. attack would provide ammunition to hard-liners who argue for acquiring a nuclear deterrent. Kroenig suggests that the United States should essentially ignore "Iran's domestic political tussles" when pursuing "its vital national security interest in preventing Tehran from developing nuclear weapons." But influencing Iranian opinion about the strategic desirability of nuclear weapons might ultimately offer the only enduring way of keeping the Islamic Republic on a peaceful nuclear path.

Finally, if Iran did attempt to restart its nuclear program after an attack, it would be much more difficult for the United States to stop it. An assault would lead Iran to distance itself from the IAEA and perhaps to pull out of the Nuclear Non-proliferation Treaty altogether. Without inspectors on the ground, the international community would struggle to track or slow Tehran's efforts to rebuild its program.

CONTAIN YOURSELF

Kroenig argues that "a nuclear-armed Iran would not intentionally launch a suicidal nuclear war" but still concludes that it is ultimately less risky to attack the Islamic Republic now than to attempt to contain it later. He warns that containment would entail a costly forward deployment of large numbers of U.S. forces on Iran's periphery for decades.

But the United States already has a large presence encircling Iran. Forty thousand U.S. troops are stationed in the Gulf, accompanied by strike aircraft, two aircraft carrier strike groups, two Aegis ballistic missile defense ships, and multiple Patriot antimissile systems. On Iran's eastern flank, Washington has another 90,000 troops deployed in Afghanistan and thousands more supporting the Afghan war in nearby Central Asian states. Kroenig claims that it would take much more to contain a nuclear-armed Iran. But U.S. forces in the Gulf already outnumber those in South Korea that are there to deter a nuclear-armed North. It is thus perfectly conceivable that the existing U.S. presence in the region, perhaps supplemented by a limited forward deployment of nuclear weapons and additional ballistic missile defenses, would be sufficient to deter a nuclear-armed Iran from aggression and blackmail.

To be sure, such a deterrence-and-containment strategy would be an extra-ordinarily complex and risky enterprise, and there is no doubt that prevention is preferable. Given the possible consequences of a nuclear-armed Iran, the price of failure would be very high. But Kroenig's approach would not solve the problem. By presenting the options as either a near-term strike or long-term containment, Kroenig falls into the same trap that advocates of the Iraq war fell into a decade ago: ignoring postwar scenarios. In reality, the strike that Kroenig recommends would likely be a prelude to containment, not a substitute for it.

Since a military raid would not permanently eliminate Iran's nuclear infrastructure, the United States would still need to construct an expensive, risky postwar containment regime to prevent Iran from reconstituting the program, much as it did in regard to Iraq after the Gulf War. The end result would be strikingly similar to the one that Kroenig criticizes, requiring Washington to maintain sufficient air, naval, and ground forces in the Persian Gulf to attack again at a moment's notice.

A strike carried out in the way Kroenig advocates—a unilateral preventive attack—would also make postwar containment more difficult and costly. Many countries would view such an operation as a breach of international law, shattering the consensus required to maintain an effective poststrike containment regime. The likelihood that the United States could "reduce the political fallout of military action by building global support for it in advance," as Kroenig suggests, would be extremely low absent clear evidence that Iran is dashing for a bomb. Without such evidence, Washington would be left to bear the costs of an attack and the resulting containment regime alone.

Finally, the surgical nature of Kroenig's proposed strike, aimed solely at Iran's nuclear program, would make postwar containment much harder. It would leave Tehran wounded and aggrieved but still capable of responding. Kroenig's recommended approach, then, would likely be just enough to ensure a costly, long-term conflict without actually compelling Iran to change its behavior.

THE OPTIONS ON THE TABLE

In making the case for preventive war as the least bad option, Kroenig dismisses any prospect of finding a diplomatic solution to the U.S.-Iranian standoff. He concludes that the Obama administration's dual-track policy of engagement and pressure has failed to arrest Iran's march toward a bomb, leaving Washington with no other choice but to bomb Iran.

But this ignores the severe economic strain, isolation, and technical challenges that Iran is experiencing. After years of dismissing the economic effects of sanctions, senior Iranian officials now publicly complain about the intense pain the sanctions are producing. And facing the prospect of U.S. sanctions against Iran's central bank and European actions to halt Iranian oil imports, Tehran signaled in early January some willingness to return to the negotiating table. Washington must test this willingness and, in so doing, provide Iran with a clear strategic choice: address the concerns of the international community regarding its nuclear program and see its isolation lifted or stay on its current path and face substantially higher costs. In framing this choice, Washington must be able to assert that like-minded states are prepared to implement oil-related sanctions, and the Obama administration should continue to emphasize that all options, including military action, remain on the table.

Some will undoubtedly claim that highlighting the potential risks associated with war will lead the Iranians to conclude that the United States lacks the resolve to use force. But in authorizing the surge in Afghanistan, carrying out the raid that killed Osama bin Laden, and leading the NATO air campaign to oust Libya's Muammar al-Qaddafi, President Barack Obama has repeatedly shown that he is willing to accept risk and use force—both as part of a coalition and unilaterally—to defend U.S. interests. And as Martin Dempsey, chairman of the U.S. Joint Chiefs of Staff, told CNN late last December, the United States has a viable contingency plan for Iran if force is ultimately required. But given the high costs and inherent uncertainties of a strike, the United States should not rush to use force until all other options have been exhausted and the Iranian threat is not just growing but imminent. Until then, force is, and should remain, a last resort, not a first choice.

Read more at Foreign Affairs' The Iran Debate: To Strike or Not to Strike.