After Iran Gets the Bomb

The Islamic Republic of Iran is determined to become the world's tenth nuclear power. It is defying its international obligations and resisting concerted diplomatic pressure to stop it from enriching uranium. It has flouted several UN Security Council resolutions directing it to suspend enrichment and has refused to fully explain its nuclear activities to the International Atomic Energy Agency. Even a successful military strike against Iran's nuclear facilities would delay Iran's program by only a few years, and it would almost certainly harden Tehran's determination to go nuclear. The ongoing political unrest in Iran could topple the regime, leading to fundamental changes in Tehran's foreign policy and ending its pursuit of nuclear weapons. But that is an outcome that cannot be assumed. If Iran's nuclear program continues to progress at its current rate, Tehran could have the nuclear material needed to build a bomb before U.S. President Barack Obama's current term in office expires.

The dangers of Iran's entry into the nuclear club are well known: emboldened by this development, Tehran might multiply its attempts at subverting its neighbors and encouraging terrorism against the United States and Israel; the risk of both conventional and nuclear war in the Middle East would escalate; more states in the region might also want to become nuclear powers; the geopolitical balance in the Middle East would be reordered; and broader efforts to stop the spread of nuclear weapons would be undermined. The advent of a nuclear Iran -- even one that is satisfied with having only the materials and infrastructure necessary to assemble a bomb on short notice rather than a nuclear arsenal -- would be seen as a major diplomatic defeat for the United States. Friends and foes would openly question the U.S. government's power and resolve to shape events in the Middle East. Friends would respond by distancing themselves from Washington; foes would challenge U.S. policies more aggressively.

Such a scenario can be avoided, however. Even if Washington fails to prevent Iran from going nuclear, it can contain and mitigate the consequences of Iran's nuclear defiance. It should make clear to Tehran that acquiring the bomb will not produce the benefits it anticipates but isolate and weaken the regime. Washington will need to lay down clear "redlines" defining what it considers to be unacceptable behavior -- and be willing to use military force if Tehran crosses them. It will also need to reassure its friends and allies in the Middle East that it remains firmly committed to preserving the balance of power in the region.

Containing a nuclear Iran would not be easy. It would require considerable diplomatic skill and political will on the part of the United States. And it could fail. A nuclear Iran may choose to flex its muscles and test U.S. resolve. Even under the best circumstances, the opaque nature of decision-making in Tehran could complicate Washington's efforts to deter it. Thus, it would be far preferable if Iran stopped -- or were stopped -- before it became a nuclear power. Current efforts to limit Iran's nuclear program must be pursued with vigor. Economic pressure on Tehran must be maintained. Military options to prevent Iran from going nuclear must not be taken off the table.

But these steps may not be enough. If Iran's recalcitrant mullahs cross the nuclear threshold, the challenge for the United States will be to make sure that an abhorrent outcome does not become a catastrophic one. This will require understanding how a nuclear Iran is likely to behave, how its neighbors are likely to respond, and what Washington can do to shape the perceptions and actions of all these players.

MESSIANIC AND PRAGMATIC

Iran is a peculiarity: it is a modern-day theocracy that pursues revolutionary ideals while safeguarding its practical interests. After three decades of experimentation, Iran has not outgrown its ideological compunctions. The founder of the Islamic Republic, Ayatollah Ruhollah Khomeini, bequeathed to his successors a clerical cosmology that divides the world between oppressors and oppressed and invests Iran with the mission of redeeming the Middle East for the forces of righteousness. But the political imperative of staying in power has pulled Iran's leaders in a different direction, too: they have had to manage Iran's economy, meet the demands of the country's growing population, and advance Iran's interests in a turbulent region. The clerical rulers have been forced to strike agreements with their rivals and their enemies, occasionally softening the hard edges of their creed. The task of governing has required them to make concessions to often unpalatable realities and has sapped their revolutionary energies. Often, the clash of ideology and pragmatism has put Iran in the paradoxical position of having to secure its objectives within a regional order that it has pledged to undermine.

To satisfy their revolutionary impulses, Iran's leaders have turned anti-Americanism and a strident opposition to Israel into pillars of the state. Tehran supports extremist groups, such as Hamas, Hezbollah, and the Islamist militias opposing U.S. forces in Iraq. The mullahs have sporadically attempted to subvert the U.S.-allied sheikdoms of the Persian Gulf. But the regime has survived because its rulers have recognized the limits of their power and have thus mixed revolutionary agitation with pragmatic adjustment. Although it has denounced the United States as the Great Satan and called for Israel's obliteration, Iran has avoided direct military confrontation with either state. It has vociferously defended the Palestinians, but it has stood by as the Russians have slaughtered Chechens and the Chinese have suppressed Muslim Uighurs. Ideological purity, it seems, has been less important than seeking diplomatic cover from Russia and commercial activity with China. Despite their Islamist compulsions, the mullahs like power too much to be martyrs.

Iran's nuclear program has emerged not just as an important aspect of the country's foreign relations but increasingly as a defining element of its national identity. And the reasons for pursuing the program have changed as it has matured. During the presidencies of Hashemi Rafsanjani and Muhammad Khatami, nuclear weapons were seen as tools of deterrence against the United States and Saddam Hussein's regime, among others. The more conservative current ruling elite, including President Mahmoud Ahmadinejad and the Revolutionary Guards, sees them as a critical means of ensuring Iran's preeminence in the region. A powerful Iran, in other words, requires a robust and extensive nuclear infrastructure. And this may be all the more the case now that Iran is engulfed in the worst domestic turmoil it has known in years: these days, the regime seems to be viewing its quest for nuclear self-sufficiency as a way to revive its own political fortunes.

Going nuclear would empower Iran, but far less than Tehran hopes. Iran's entry into the nuclear club would initially put Tehran in a euphoric mood and likely encourage it to be more aggressive. The mullahs would feel themselves to be in possession of a strategic weapon that would enhance Iran's clout in the region. They might feel less restrained in instigating Shiite uprisings against the Arab sheikdoms in the Persian Gulf. But any efforts to destabilize their Sunni neighbors would meet the same unsuccessful fate as have similar campaigns in the past. Iran's revolutionary message has traditionally appealed to only a narrow segment of Shiites in the Persian Gulf. Sporadic demonstrations in Bahrain and Saudi Arabia have not sought to emulate Iran's revolution; rather, they have been an outlet for Shiites to express their economic and political disenfranchisement.

A nuclear Iran might also be tempted to challenge its neighbors in the Persian Gulf to reduce their oil production and limit the presence of U.S. troops on their territories. However, obtaining nuclear weapons is unlikely to help Iran achieve these aims, because nuclear weapons, by definition, are such a narrow category of arms that they can accomplish only a limited set of objectives. They do offer a deterrent capability: unlike Saddam's Iraq, a nuclear Iran would not be invaded, and its leaders would not be deposed. But regime security and power projection are two very different propositions. It is difficult to imagine Sunni regimes yielding to a resurgent Shiite state, nuclear or not; more likely, the Persian Gulf states would take even more refuge under the U.S. security umbrella. Paradoxically, a weapon that was designed to ensure Iran's regional preeminence could further alienate it from its neighbors and prolong indefinitely the presence of U.S. troops on its periphery. In other words, nuclear empowerment could well thwart Iran's hegemonic ambitions. Like other nuclear aspirants before them, the guardians of the theocracy might discover that nuclear bombs are simply not good for diplomatic leverage or strategic aggrandizement.

Likewise, although the protection of a nuclear Iran might allow Hamas, Hezbollah, and other militant groups in the Middle East to become both more strident in their demands and bolder in their actions, Israel's nuclear arsenal and considerable conventional military power, as well as the United States' support for Israel, would keep those actors in check. To be sure, Tehran will rattle its sabers and pledge its solidarity with Hamas and Hezbollah, but it will not risk a nuclear confrontation with Israel to assist these groups' activities. Hamas and Hezbollah learned from their recent confrontations with Israel that waging war against the Jewish state is a lonely struggle.

The prospect that Iran might transfer a crude nuclear device to its terrorist protégés is another danger, but it, too, is unlikely. Such a move would place Tehran squarely in the cross hairs of the United States and Israel. Despite its messianic pretensions, Iran has observed clear limits when supporting militias and terrorist organizations in the Middle East. Iran has not provided Hezbollah with chemical or biological weapons or Iraqi militias with the means to shoot down U.S. aircraft. Iran's rulers understand that such provocative actions could imperil their rule by inviting retaliation. On the other hand, by coupling strident rhetoric with only limited support in practice, the clerical establishment is able to at once garner popular acclaim for defying the West and oppose the United States and Israel without exposing itself to severe retribution. A nuclear Iran would likely act no differently, at least given the possibility of robust U.S. retaliation. Nor is it likely that Iran would become the new Pakistan, selling nuclear fuel and materials to other states. The prospects of additional sanctions and a military confrontation with the United States are likely to deter Iran from acting impetuously.

A nuclear Iran would undeniably pose new dangers in the Middle East, especially at first, when it would likely be at its most reckless. It might thrash about the Middle East, as it tried to press the presumed advantages of its newfound capability, and it might test the United States' limits. But the mullahs will find it difficult to translate Iran's nuclear status into a tangible political advantage. And if Washington makes clear that rash actions on their part will come at a high cost, they will be far less likely to take any.

THE RIPPLES IN THE REGION

In assessing the consequences of Iran's nuclearization, it is important to consider not only how Iran is likely to act but also how other states will react to this outcome -- and what the United States could do to influence their responses. Iran's nuclearization would not reduce Washington to passively observing events in the region. Washington would retain considerable ability to shape what Iran's neighbors do and do not do.

The nightmare scenario that could be unleashed by Iran's nuclearization is easy to sketch. Israel would go on a hair-trigger alert -- ready to launch a nuclear weapon at a moment's notice -- putting both countries minutes away from annihilation. Egypt, Saudi Arabia, and Turkey would scramble to join the nuclear club. The Nonproliferation Treaty (NPT) would collapse, unleashing a wave of nuclear proliferation around the globe.

Such a doomsday scenario could pan out. Whether it did would depend greatly on how the United States and others, starting with Israel, responded to Iran's nuclearization. Whether Israeli Prime Minister Benjamin Netanyahu forgoes a preventive strike against Iran's nuclear facilities or opts for launching an attack and it fails, the Israeli government will continue to regard the Iranian regime as an existential threat to Israel that must be countered by any means possible, including the use of nuclear weapons. Given Israel's unique history and Ahmadinejad's contemptible denials of the Holocaust, no Israeli prime minister can afford to think otherwise.

The riskiness of a nuclear standoff between Israel and Iran would vary with the nature and size of Tehran's nuclear arsenal. An Iran with only the capability to build a nuclear weapon would pose a far less immediate threat to Israel than an Iran that possessed an actual weapon. Iran's possession of a bomb would create an inherently unstable situation, in which both parties would have an incentive to strike first: Iran, to avoid losing its arsenal, and Israel, to keep Tehran from using it. The Israeli government's calculations about Iran would depend on its assessment of the United States' willingness and ability to deter Iran. Israel's decision-making would be shaped by a number of factors: the United States' long-standing support for Israel, Israel's doubts about U.S. leadership after Washington's failure to stop Iran from going nuclear, and Washington's response to Iran's nuclearization.

Another danger that would have to be countered would be nuclear proliferation in the Middle East. Iran's regional rivals might try to catch up with it. History suggests, however, that states go nuclear for reasons beyond tit for tat; many hold back even when their enemies get nuclear weapons. China's pursuit of the bomb in the 1960s prompted fears that Japan would follow, but nearly half a century later, Japan remains nonnuclear. Although Israel has more than 200 nuclear weapons, neither its neighbors -- not even Egypt, which fought and lost four wars with Israel -- nor regional powers, such as Saudi Arabia or Turkey, have followed its lead.

An Iranian nuclear bomb could change these calculations. The U.S. National Intelligence Council concluded in a 2008 report that "Iran's growing nuclear capabilities are already partly responsible for the surge of interest in nuclear energy in the Middle East." And nuclear energy programs can serve as the foundation for drives for nuclear weapons. But it would not be easy for countries in the region to get nuclear weapons. Many lack the infrastructure to develop their own weapons and the missiles needed to deliver them. Egypt and Turkey might blanch at the expense of building a nuclear arsenal. The Pakistanis were willing to "eat grass" for the privilege of joining the nuclear club, as the Pakistani leader Zulfikar Ali Bhutto once famously put it, but not everyone is.

Cost considerations aside, it would take years for nuclear aspirants to develop indigenous nuclear capabilities. They would need to build nuclear reactors, acquire nuclear fuel, master enrichment or reprocessing technologies, and build weapons and the means to deliver them. While they tried, the United States and other states would have ample opportunity to increase the costs of proliferation. Indeed, the economic and security interests of Egypt, Saudi Arabia, and Turkey, unlike those of Iran, are tied to the United States and the broader global economy, and developing nuclear weapons would put those interests at risk. Egypt would jeopardize the $1.5 billion in economic and military aid that it receives from Washington each year; Saudi Arabia, its implicit U.S. security guarantee; and Turkey, its place in NATO. Given their extensive investments in and business ties to the United States and Europe, all three countries would be far more vulnerable than Iran is to any economic sanctions that U.S. law imposed, or could impose, on nuclear proliferators.

States seeking nuclear weapons might try to sidestep these technological and political hurdles by buying, rather than making, the weapons. Saudi Arabia's clandestine acquisition of medium-range ballistic missiles from China in the 1980s suggests that even countries that depend on U.S. security guarantees might be tempted to buy their way into the nuclear club. Although neither the five acknowledged nuclear powers nor India would be likely to sell nuclear weapons to another state, Pakistan and North Korea could be another matter. Both countries have a history of abetting proliferation, and Pakistan has warm ties with its fellow Muslim-majority countries. But selling complete nuclear weapons would come at great political cost. Pakistan might forfeit U.S. foreign assistance and drive the United States into closer cooperation with India, Pakistan's mortal enemy. North Korea would endanger the economic aid it gets from China, which the regime needs to stay in power.

If a buyer did manage to find a seller, it would have to avoid a preventive strike by Israel -- which would be likely if the sale became known before the weapon was activated -- and then handle the inevitable international political and economic fallout. (In 1988, Saudi Arabia avoided a major rift with Washington over its missile deal with China only by finally agreeing to sign and abide by the NPT.) Furthermore, any country that bought a nuclear weapon would have to worry about whether it would actually work; in global politics, as in everyday life, swindles are possible. Obtaining a nuclear weapon could thus put a country in the worst of all worlds: owning a worthless weapon that is a magnet for an attack.

If Iran's neighbors decided against trying to get nuclear weapons, they could pursue the opposite approach and try to appease Tehran. The temptation would be greatest for small Persian Gulf states, such as Bahrain and Kuwait, which sit uncomfortably close to Iran and have large Shiite populations. Such a tilt toward Iran would damage U.S. interests in the region. The U.S. Fifth Fleet is based in Bahrain, and U.S. military bases in Bahrain, Kuwait, and the United Arab Emirates are crucial to projecting U.S. power and reassuring U.S. allies in the region. But as long as these governments believe that Washington is committed to their security, appeasement will be unappealing. Pursuing that strategy would mean casting aside U.S. help and betting on the mercy of Tehran. In the absence of a U.S. security guarantee, however, Iran would be free to conduct in those countries the very subversive activities that their governments' appeasement was intended to prevent.

Although Iran's nuclearization would probably not spell the end of efforts to halt proliferation in other parts of the world, it would undeniably deal the nonproliferation regime a setback, by demonstrating that the great powers are unable or unwilling to act collectively to stop proliferators. On the other hand, most states adhere to the NPT because they have compelling national reasons to do so. They may not feel threatened by a nuclear power; they may be covered by the nuclear umbrella of another state; they may lack the financial or technological wherewithal to build a bomb. Iran's success in developing a nuclear weapon would not change these calculations. Nor would it prevent Washington from pushing ahead with its efforts to strengthen the Proliferation Security Initiative (a U.S.-led multinational effort launched by the Bush administration that seeks to stop trafficking in weapons of mass destruction), impose a cutoff on the further production of fissile material, tighten global rules on trade in nuclear materials, and otherwise make it more difficult for nuclear technologies to spread.

Iran's acquisition of a nuclear bomb could have disastrous consequences in the Middle East. But Washington would have considerable opportunities to influence, and constrain, how Iran's neighbors reacted to its new status. It would matter whether Washington reassured Israel or fueled its fears. It would matter whether Washington confronted regional proliferation efforts or turned a blind eye, as it did with Pakistan in the 1980s. It would matter whether Washington pushed ahead with efforts to strengthen the NPT regime or threw in the towel. To keep the nightmare scenario at bay, the United States will need to think carefully about how to maximize its leverage in the region.

I SAY NO, NO, NO

Tehran is an adversary that speaks in ideological terms, wants to become a dominant regional power, and is capable of acting recklessly. But it is also an adversary that recognizes its limitations, wants to preserve its hold on power, and operates among wary neighbors. Its acquiring a nuclear bomb, or the capacity to make a nuclear bomb, need not remake the Middle East -- at least not if the United States acts confidently and wisely to exploit Iran's weaknesses.

Any strategy to contain Iran must begin with the recognition that this effort will have to be different from that to contain the Soviet Union. Iran poses a different threat. During the early years of the Cold War, U.S. policymakers tried to protect like-minded countries against a Soviet invasion that would have imposed communist rule, or against widespread economic dislocation, which could have produced a communist takeover from within. Their strategy was to turn to the NATO alliance and launch the Marshall Plan. The United States' containment strategy toward Iran must reflect different realities today. Iran does not seek to invade its neighbors, and its ideological appeal does not rest on promises of economic justice. It seeks to establish itself as the dominant power in the region while preserving political control at home.

Deterrence would by necessity be the cornerstone of a U.S. strategy to contain a nuclear Iran. Success is by no means guaranteed. Deterrence can fail: it nearly did during the Cuban missile crisis, in 1962, and at several other critical junctures of the Cold War. Iran's revisionist aims and paranoia about U.S. power may appear to make the country uniquely difficult to deter. But that conclusion conveniently -- and mistakenly -- recasts the history of U.S. confrontations with emerging nuclear powers in a gentler light than is deserved. At the start of the Cold War, U.S. officials hardly saw the Soviet Union as a status quo power. In the 1960s, China looked like the ultimate rogue regime: it had intervened in Korea and gone to war with India, and it repressed its own people. Mao boasted that although nuclear war might kill half the world's population, it would also mean that "imperialism would be razed to the ground and the whole world would become socialist."

Today, the challenge for U.S. policymakers devising a deterrence strategy toward Iran will be to unambiguously identify what behavior they seek to deter -- and what they are willing to do about it. When Washington publicly presents its policy on how to contain a nuclear Iran, it should be explicit: no initiation of conventional warfare against other countries; no use or transfer of nuclear weapons, materials, or technologies; and no stepped-up support for terrorist or subversive activities. It should also make clear that the price of Iran's violating these three prohibitions could be U.S. military retaliation by any and all means necessary, up to and including nuclear weapons.

The pledge to deter a conventional attack would be the easiest of the three prohibitions to enforce. Iran's ability to project sustained military power outside its borders is limited. And it is unlikely to grow substantially anytime soon: even more arms embargoes would likely be imposed on Iran if it crossed the nuclear threshold. At their current level, U.S. troops in the region are more than sufficient to deter Iran from undertaking incursions into Iraq or amphibious operations across the Persian Gulf -- or to stop them if they occurred.

Deterring Iran from using or threatening to use nuclear weapons would present a different set of challenges. So long as Iran lacks the ability to strike the United States with a nuclear-tipped missile, the United States can credibly threaten to retaliate militarily if Iran uses or threatens to use a nuclear bomb against anyone. But that could change if Iran developed long-range missiles. Tehran might also try to deter the United States by threatening to attack Europe, which would raise well-known concerns about the viability of so-called extended deterrence, the ability of one state to deter an attack on another. These possibilities highlight the importance of developing robust, multilayered ballistic missile defenses. The Obama administration's decision to reorient U.S. missile defenses in Europe to protect against shorter-range missiles while continuing to develop defenses against longer-range missiles is just the right approach.

A tougher challenge would be to ensure stable deterrence between Iran and Israel. With regard to this issue, too, the Iranian nuclear program's ultimate degree of development would be pivotal: an Iran armed with nuclear weapons would present a significantly more dangerous threat than one that merely had the capacity to build them. It is thus essential that Washington continue to apply diplomatic and economic pressure to keep Tehran, should it manage to complete the nuclear fuel cycle, from taking the final step. The United States should also publicly pledge to retaliate by any means it chooses if Iran uses nuclear weapons against Israel; this would in effect supplement whatever second-strike capability Israel has. If the Israelis need a formal commitment to be more reassured, this pledge could be made in an executive agreement or a treaty. As a tangible expression of its commitment, Washington should also be prepared to deploy U.S. troops on Israeli soil as a tripwire, which would show that the United States would be inextricably bound to Israel in the event of any Iranian attack.

Washington should also inform Tehran that it would strike preemptively, with whatever means it deemed necessary, if Iran ever placed its nuclear forces on alert. And it should bring both Israel and Israel's Arab neighbors fully under its missile defense umbrella. The more aggressive Iran is, the more inclined its neighbors will be to work with Washington to construct missile defenses on their territories.

Deterring Iran from transferring nuclear weapons, materials, and technologies to state and nonstate actors would require another set of measures. For the most part, Iran has reasons not to pursue such perilous activities, but it could be tempted to exploit the difficulty of tracking the clandestine trade in nuclear materials. The United States and its allies would need to act decisively to prevent Tehran from seeking to profit in the international nuclear bazaar, for example, through the Proliferation Security Initiative and through UN resolutions that imposed additional sanctions on Iran and its potential business partners. To impress on Iran's ruling mullahs that it is singularly important for them to control whatever nuclear arsenal they may develop or obtain, Washington should hold Tehran responsible for any nuclear transfer, whether authorized or not; Tehran cannot be allowed to escape punishment or retaliation by pleading loss of control. Increased investments in monitoring and spying on Iran would be critical. The United States must improve its ability to track nuclear weapons, materials, and debris and prove and publicize whether they came from Iran (or any other country, for that matter). Such nuclear forensics is crucial to determining who is responsible for nuclear transfers and would be crucial to building support for any U.S. retaliation against Iran, if it were the culprit.

Deterring Iranian support for terrorist and subversive groups -- the third redline prohibition that the United States should impose -- would be difficult. Such activities take place secretly, making it hard to establish precisely who is complicit. That complication places a premium on improving the ability of the U.S. intelligence community, acting alone and in concert with its counterparts abroad, to track Iran's clandestine activities.

WHATS AND WHAT NOTS

In addition to holding Iran accountable for violating any of the three noes, the United States' containment strategy should seek to influence and, where necessary, constrain Iran's friends in the Middle East. An energetic diplomacy that softened the disagreements between Israel and its neighbors would undermine Iran's efforts to exploit anger in the region. A concerted push, diplomatic and economic, to improve the lives of the Palestinians would limit Iran's appeal among them. Drawing Syria into a comprehensive Israeli-Palestinian peace process could not only attenuate Tehran's links with Damascus but also stem Iran's ability to supply weapons to Hezbollah. Washington should seek to further limit Iran's strategic reach by strengthening the institutional and military capabilities of Afghanistan and Iraq. It should reassure the Persian Gulf states that it is committed to preserving the existing balance of power, which would require expanding trade agreements, enhancing their security and intelligence apparatuses, and developing a more integrated approach to defense planning in the region. At the same time, the United States will need to dissuade these governments from further suppressing their Shiite minorities, a practice that inadvertently aids Tehran. And it should work assiduously to prevent more countries in the Middle East from going nuclear; the United States cannot look the other way again, as it did with Pakistan during the 1980s.

Tone and conviction will matter. Washington must keep in mind that Iran's entry into the nuclear club would be read by Israel and Arab states as a failure of the United States' political will and a demonstration of the limits of U.S. power. Washington cannot afford to compound its credibility problem by hesitating or vacillating. An indecisive U.S. response would undermine the efforts both to deter Iran and to reassure U.S. friends and allies in the region.

Washington should also push other major powers to contain the Iranian threat. The five permanent members of the UN Security Council have sponsored numerous resolutions demanding that Iran cease its nuclear activities and cooperate with the International Atomic Energy Agency. They should have a vested interest in punishing Iran, an original signatory to the NPT, if it reneges on its decades-old pledge to remain a nonnuclear power. Doing nothing would substantially undermine the UN Security Council's authority and with it their status as permanent members of the council. Europe should be pressed to commit troops and naval vessels to preserve the free flow of traffic through the Persian Gulf. Russia should cease its nuclear cooperation with and its conventional arms sales to Iran. China should be pressed to curtail its investment in Iran's energy sector, which does so much to fuel Iran's belligerence. The United States would have to do much of the heavy lifting in containing a nuclear Iran, but any concerted containment strategy must have not just regional support but also an international complexion.

Just as important as what Washington should do to contain Iran is what it should not do. If Iran gets a nuclear bomb, the United States might be tempted to respond by substantially expanding the presence of U.S. troops in the Middle East. But this would not appreciably increase Washington's ability to deter Iran from launching a nuclear or conventional attack; there are already enough U.S. forces in the region for that. It could, however, play into the hands of Tehran's proxies by inflaming anti-American sentiment and fanning civil unrest in the Persian Gulf.

Washington might also be tempted to seek to further undermine Iran's economy by imposing broad-based economic sanctions, an idea that enjoys considerable support on Capitol Hill. But such measures would wind up punishing only Iran's disenfranchised citizenry (which is why Iranian opposition leaders have strenuously opposed them). The wiser course of action would be to strengthen and better monitor existing export controls, in order to make certain that Iran's nuclear and defense industries do not have access to dual-use technologies, and to reinforce targeted sanctions against the Iranian leadership and the business enterprises controlled by the Revolutionary Guards. Washington should push, both inside and outside the UN, for travel bans on Iranian leaders and measures denying Iran access to capital markets, for example. It should also find ways to penalize foreign businesses that invest in Iran's dilapidated oil industry. Smart sanctions of this kind would punish Iran's leaders but spare ordinary Iranians, who have no say over the regime's actions.

The United States should refrain from greatly expanding the range of weaponry it sells to the Persian Gulf states, which see the United States as a military guarantor and their chief arms supplier. To some extent, increasing arms sales will be necessary: the Arab governments of the region would regard such sales as a tangible sign of the strength of Washington's commitment to their defense, and if Washington holds back, these governments will look for weapons elsewhere. On the other hand, throwing the doors of the armory wide open would do little to secure the buyers and might even increase instability in the region. A smart U.S. arms sales policy would focus on offering weapons systems that are designed to deter or help counter an Iranian attack, such as missile defense systems and command-and-control systems, which would provide advance notice of Iranian actions.

Finally, Washington should resist any urge to sign mutual security treaties with Arab countries in the Middle East. (Israel, whose relations with Iran are fundamentally different from those of every other power in the region, is a special case.) Such efforts would do little to enhance deterrence and could do a lot to undermine it. Many members of the U.S. Senate, which would have to vote on any alliance treaty, would question whether the United States should further tie itself to authoritarian regimes that many Americans find odious. The spectacle of that debate would exacerbate doubts in the Middle East about the depth of the United States' commitment. Efforts to construct formal alliances might also lead Iran to believe that any country left out of these agreements is fair game for intimidation or attack. Washington should be mindful not to invite a replay of North Korea's calculation in 1950 that South Korea lay outside the U.S. defense perimeter.

Instead, the U.S. government should encourage the formation of a regional alliance network that would marshal Arab states into a more cohesive defense grouping. The network could be organized along the lines of the Middle East Treaty Organization (then the Central Treaty Organization), a security arrangement among Iran, Pakistan, Turkey, the United Kingdom, and, for a time, Iraq (with the United States participating in the organization's military and security committees) that existed from 1955 to 1979. An alliance of this kind would secure all the benefits of a regionwide commitment to deterrence without exposing the United States and its allies to the complexities of formal bilateral or multilateral security treaties.

DANGEROUS TIMES

Iran's nuclearization would make the Middle East a more dangerous place: it would heighten tensions, reduce the margin for error, and raise the prospect of mass catastrophe. The international community should not let up on its efforts to stop Iran's progress. But given the mullahs' seeming indifference to the benefits of engagement, U.S. policymakers must consider now what to do if Iran does get the bomb.

Containment would be neither a perfect nor a foolproof policy. The task of foiling Iran's support for Hamas and Hezbollah would be difficult, as would countering Iran's support for terrorist and subversive groups in the region. The need to gain favor with Arab dictatorships would likely tempt Washington to shelve its calls for domestic political reforms in those countries -- even though such reforms could diminish Iran's ability to meddle there by improving the lot of local minority Shiites who might otherwise be susceptible to Tehran's influence. Maintaining great-power support for pressure on Iran could require overlooking objectionable Chinese and Russian behavior on other matters. Containment would not be a substitute for the use of force. To the contrary, its very success would depend on the willingness of the United States to use force against Iran or threaten to do so should Tehran cross Washington's redlines. Applying pressure without a commitment to punishing infractions is a recipe for failure -- and for a more violent and dangerous Middle East.

Containment could buy Washington time to persuade the Iranian ruling class that the revisionist game it has been playing is simply not worth the candle. Thus, even as Washington pushes to counter Iran, it should be open to the possibility that Tehran's calculations might change. To press Tehran in the right direction, Washington should signal that it seeks to create an order in the Middle East that is peaceful and self-sustaining. The United States will remain part of the region's security architecture for the foreseeable future, but it need not maintain an antagonistic posture toward Iran. An Islamic Republic that abandoned its nuclear ambitions, accepted prevailing international norms, and respected the sovereignty of its neighbors would discover that the United States is willing to work with, rather than against, Iran's legitimate national aspirations.