LM/The National InterestIt is neither premature nor defeatist for the United States to start preparing for the possibility that Iran will acquire nuclear weapons. It is not inevitable. But the longer Americans wait to engage in an honest and calm debate about a nuclear-armed Iran, the less prepared they will be should that fateful day arrive.

Should the world be faced with the fait accompli of a nuclear Iran, the immediate reaction of the international community will be massive outrage and condemnation. The United States will be confronted with some familiar options: launch a preventive strike or accept the reality of a nuclear-armed Iran and move to a policy of Cold War–like containment and robust deterrence. This scenario prompts several questions: How would the U.S. stance toward a nuclear Iran differ from Washington’s present policy? Would the costs of containment and deterrence be significantly higher? Would a military option be completely ruled out?

The Conventional Attack

Let’s start with prevention. Launching a comprehensive attack against a nuclear Iran that seeks to physically destroy its nuclear program in full, crush its military and decapitate its political leadership is not unthinkable. But it should be obvious to all that the risks are immensely high and the costs could be intolerable for both the United States and Israel.

Iran would possess a relatively small nuclear arsenal in the beginning (anywhere between four and thirty-seven nukes) and no assured second-strike capability for years, making it vulnerable to a disarming raid by the United States. Yet Iran’s vulnerability could also complicate U.S. military plans. Iran may be compelled to strike first for fear of losing its few nukes, especially if it perceives that an attack is imminent. Further, Iran’s limited capabilities in command, control, communications and intelligence could also cause a hair-trigger reaction during a crisis.

Attacking a nuclear-armed Iran is a viable option only if Washington knows the exact number of Iran’s nuclear warheads and their locations and can ensure they will not be moved or fired before a strike. The chances that U.S. intelligence agencies will gather solid intelligence on all these variables are slim. And because nuclear weapons are relatively easy to hide and move, Iran will make sure to create operational uncertainty and strategic ambiguity, causing Washington to think twice before launching an attack. All Iran needs is the survival of one or two nukes to use against U.S. interests in the Persian Gulf or to fire at Israel. In sum, it is far from clear that a conventional attack by the United States, no matter how massive and well executed, would physically eliminate all of Iran’s nuclear weapons.

The Challenges of Containment

The elements of an alternative policy—containment and deterrence—are well-known by now. (The American Enterprise Institute’s December 2011 report, “Containing and Deterring a Nuclear Iran,” did a superb job of detailing them.) These include but are not limited to boosting defense ties with Gulf Cooperation Council states, providing them with a nuclear umbrella and deploying missile defenses on their territories, bolstering the U.S. military presence in the Persian Gulf, and solidifying diplomatic relations with U.S. allies in the region and within NATO.

The costs of this policy are also clear: An Iranian bomb would deal a huge blow to (or even totally collapse) the Nuclear Non-Proliferation Treaty, aspirations of global disarmament and the objective of a Middle East free of weapons of mass destruction. The United States, whose armed forces are already stretched thin, would need to allocate significant military resources to the Persian Gulf and spend a lot of political capital convincing its Middle Eastern allies (Turkey, Saudi Arabia, Egypt, and possibly Qatar and the UAE) not to seek their own nuclear weapons. This would be extremely difficult.

But if the United States was able to protect its allies during the Cold War from nuclear blackmail by the Soviets, it can do so with a much less powerful adversary—even an Iran in possession of the bomb. But just as with the Soviet Union, the United States would need a genuinely credible deterrent posture. A nuclear Iran must believe that Washington is both able and willing to inflict massive pain on Tehran, should it misbehave.

What Iran’s leaders say and do immediately after they get the bomb could make a difference in how the United States reacts. Clear signaling of intentions by Iran’s leaders could tip the balance in favor of a particular U.S. response. To be sure, there may not be much difference in what Iran says and does once it acquires a nuclear-weapons capability. The United States might have already decided in favor of a military strike and the domestic, regional and international pressures might be too strong—but Iran will still have a choice to make.

A Cooperative Iran?

Consider an admittedly theoretical scenario for just a moment. A nuclear Iran could reduce the chances of an American attack if it chose to take tangible and verifiable steps to convince the United States and the rest of the world that it would be a responsible and peaceful nuclear-weapons state. It would have to convey quickly and clearly that its nuclear weapons would only serve deterrent purposes and never be used as war-fighting instruments on the battlefield or as tools for blackmail and subversion.

The size and nature of Iran’s nuclear arsenal will be important indicators of its intentions. Specifically, a small, safe and reliable arsenal could be less of a concern. A declaration that specifies the conditions under which Iran would use or threaten to use nuclear weapons is another major form of signaling and an indicator of intentions. A “no-first-use” policy, a clear and public articulation of “red lines,” and the publication of a nuclear doctrine could also help reduce regional and worldwide fears, and thus lower the chances of a U.S. preventive strike. The more transparent Iran decides to be about its nuclear arsenal, the more credible its case of nonaggression will be.

Also relevant is the manner in which Iran declares its nuclear status to the world. Test-firing a nuclear weapon like the Pakistanis and the North Koreans may be a sign of worse things to come, although the Indians and some of the other nuclear powers also test-fired their devices. Keeping the bomb in the basement, however, and never acknowledging it—as the Israelis did—would be devastating to the international nonproliferation regime, but might be better received by the United States.

In addition, feeling more confident about its security and deterrent capabilities, Iran could publicly renounce terrorism, refrain from blocking peace efforts in the Middle East and stop sending arms to Hezbollah. Iran might also adopt nuclear-export controls and other nonproliferation policies, which India embraced soon after it obtained the bomb, and state its desire to participate in international arrangements to prevent or restrict sensitive flows from its civilian nuclear program.

Should a nuclear Iran decide to follow a pacific course—an outcome that is highly doubtful—the United States might shelve, but not take off the table, the option of a preventative strike, opting instead for a policy of containment and deterrence. But there is also the far more likely scenario: Iran chooses not to take the aforementioned course, thus raising the incentives of the United States to strike.

Communication Breakdown

Early signs of hostile Iranian intentions could include the production of a large nuclear arsenal that incorporates tactical nukes and the development of new military capabilities, such as an intercontinental ballistic missile, that directly threaten the United States and its allies. A rejection of a “no-first-use” principle or an ambiguous declaratory policy that leaves world governments guessing about Iranian intentions could also precipitate U.S. preventive action.

Iran could also leverage its nuclear status for political advantage, initiating crises directly or by proxy and escalating a conventional conflict. And should Iran find itself losing a conflict with a rival or enemy nation on the conventional battlefield, it could always resort to the nuclear option. Indeed, the introduction of battlefield nuclear weapons might be a tactic pursued as a last, desperate means of ensuring survival. Other signs of bellicose intentions by a nuclear Iran that could provoke a U.S. military response are a major terrorist attack against Western interests, forward troop deployments along its borders, comprehensive and aggressive military training exercises and simulations with live ammunition, and threats directed at U.S. allies.

Even if a nuclear Iran chooses to pacify the world, it must effectively communicate its peaceful intentions. Obviously this is easier said than done. For a start, Iran’s diplomatic skills are weak and its political system is factionalized. Indeed, Tehran has a record of obscuring its intentions and concealing its capabilities, and its civilian, religious and military leaders seldom speak with one voice on foreign affairs.

There is no U.S.-Iranian hotline. Diplomatic relations between Iran and its two primary enemies, the United States and Israel, do not even exist. Sending crucial messages to the United States through the Swiss channel is not ideal and cannot be a substitute for direct interaction, especially during times of nuclear crisis. The United States and its allies will not give Iran, a country whose credibility is already very low, the benefit of the doubt. There will not be an effort to understand whether Iran is failing to communicate due to unwillingness, incapacity or both; the United States and its allies will just assume and prepare for the worst.