What Will Iran Do If It Gets a Nuclear Bomb?

Five experts predict how a nuclear bomb would or wouldn't change Tehran's behavior.

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Iranian President Mahmoud Ahmadinejad attends an unveiling ceremony of new nuclear projects in Tehran / Reuters

In 1995, Kenneth Waltz and Scott Sagan coauthored the book, The Spread of Nuclear Weapons: A Debate, which sought to address the question: what are the likely consequences of the spread of nuclear weapons?

In a self-help international system, Waltz contended, "states must rely on the means they can generate and the arrangements they can make for themselves." He argued that a second-strike nuclear capability is the most reliable means for a state to assure its survival by dissuading other states from attacking. Due to fears of escalation, "new nuclear states will feel the constraints that present nuclear states have experienced."

Sagan, meanwhile, countered Waltz's optimism with two arguments based in organizational theory. First, "professional military organizations--because of common biases, inflexible routines, and parochial interests--display organizational behaviors that are likely to lead to deterrence failures and deliberate or accidental war." Second, "future nuclear-armed states will lack the positive mechanisms of civilian control." Sagan therefore called for a U.S. nonproliferation policy that includes reaffirming to nascent nuclear states that the bomb "will make their states targets for preventive attacks by their potential adversaries, will not easily lead to survivable arsenals, and will raise the specter of accidental or unauthorized uses of nuclear weapons."

This academic discussion has direct relevance to the ongoing policy debate over Iran, and whether Israel, the United States, or some combination of states should use preemptive military force against the regime's suspected nuclear weapons program. We cannot ask the Iranian government directly what they would do with a bomb, because it continues to maintain that its nuclear program is entirely peaceful for the purposes of producing nuclear power and medical diagnostic isotopes. Nevertheless, as President Obama stated recently, it is U.S. policy "to do everything we can to prevent Iran from getting a nuclear weapon and creating an arms race, a nuclear arms race, in a volatile region."

To explore this issue further, I asked several international relations and security studies scholars who have extensively researched and written on the topic of nuclear proliferation to contribute their thoughts on the impact of a potential Iranian nuclear weapon. Specifically, I asked:

"If the international community believed--through testing or intelligence estimates--that Iran possessed a nuclear weapon, what impact would the bomb have on Iranian foreign policy?"


Kyle Beardsley is Assistant Professor of Political Science at Emory University and is the author of The Mediation Dilemma.

A nuclear-armed Iran is not likely to act much differently. Most importantly, Iran will have no incentive to use its nuclear weapons in aggression; doing so against Israeli or American targets would gain Iran little and cost it much. On a more practical level, an Iranian bomb also will not substantially change the general strategic dynamics. In a series of articles, Victor Asal and I have shown that states with nuclear weapons tend to face less hostility from opponents, be in shorter crises, and prevail more often in their crises against non-nuclear states.

The logic is that nuclear weapons are an effective deterrent that temper aggression. According to this logic, the main benefit to Iran of acquiring nuclear weapons is to deter military threats by its primary adversaries, Israel and the United States. Given that Iran already has a strong deterrent--via its importance to hydrocarbon supplies, robust conventional forces, ability to disrupt fragile situations in Lebanon and Iraq, and Western war weariness--it is doubtful that Iran will notice much immediate advantage from obtaining nuclear weapons. Its main incentive for proliferating apparently is to lock in the regime's security in the long run. Victor Asal and I also find that proliferators are sources of instability prior to attaining weapons, so a modest upside to successful proliferation would be movement away from the current alarming exchanges.


Sarah Kreps is Assistant Professor in the Department of Government at Cornell University and is the author of Coalitions of Convenience: United States Military Interventions after the Cold War.

To answer this question, we should distinguish between Iran's bark and bite.

Having a nuclear weapon would give Iran a bigger bark. Armed with the bomb, Iran could make threats that might win it economic aid and political concessions. Influence, as Schelling noted, comes from "the power to hurt," and nuclear weapons provide the ultimate power to hurt.  Having such "latent violence" in the form of nuclear weapons can translate into considerable bargaining influence. The North Korea model is instructive here. The Kim Jong-il regime used its nuclear program as a bargaining chip, promising to dismantle its Yongbyon reactor in exchange for political concessions and economic aid. Often they gained concessions, however, while only temporarily or incompletely complying with their end of the bargain.

On the other hand, it seems doubtful that having the bomb would give Iran a bigger bite. Rather, there's every reason to believe that deterrence theory should hold. How much influence Iran's weapons can confer, again drawing on Schelling, "will indeed depend on how much the adversary can hurt in return."  Iran's primary rivals are Israel and the United States, each with arsenals that are far more lethal than what Iran could assemble even over the next decade. That each has enough weapons to hurt Iran quite badly should be enough to keep Iran's bite in check.


Matthew Kroenig is Assistant Professor of Government at Georgetown University and a Stanton Nuclear Fellow at the Council on Foreign Relations. He is the author of Exporting the Bomb: Technology Transfer and the Spread of Nuclear Weapons.

A nuclear-armed Iran would pose a grave threat to international peace and security.  It would lead to further nuclear proliferation as other countries in the region sought nuclear weapons in response.  As I discuss in Exporting the Bomb, a nuclear Iran would likely become a nuclear supplier and transfer uranium enrichment technology--the basis for dangerous nuclear programs--to U.S. enemies in regions around the world.

Iran currently restrains its foreign policy for fear of U.S. military retaliation, but with a nuclear counter-deterrent it would be emboldened to push harder, stepping up support for terrorist groups, brandishing nuclear weapons for coercive purposes, and adopting a more aggressive foreign policy. A nuclear Iran could constrain U.S. freedom of action in the Middle East by threatening nuclear war in response to major U.S. initiatives in the region.

A more aggressive Iran would lead to an even more crisis-prone region, and any crisis involving a nuclear-armed Iran could spiral out of control and result in a nuclear war against Israel or even, once Iran has developed the requisite delivery vehicles, the U.S. homeland.

In sum, a nuclear-armed Iran would pose a severe threat that Washington would have to live with as long as Iran exists as a state and has nuclear weapons, which could be decades or even longer.


Annie Tracy Samuel is a Research Fellow in the International Security Program at the Harvard Kennedy School's Belfer Center for Science and International Affairs and a PhD candidate in the Graduate School of History at Tel Aviv University. Her research focuses on the Iranian Revolutionary Guards, Iran-Iraq war, and Iranian security and foreign policy.

Iran's possession of a nuclear weapon would be a troubling and disturbing development, especially for the future of the nonproliferation regime and for stability in the Middle East.  However, there is reason to believe that Iran's theoretical possession of a nuclear weapon would not profoundly alter the essence of its foreign policy.

Iran's foreign policy, both before and after the 1979 revolution, has been largely pragmatic, particularly in action if not always in rhetoric. Though it has miscalculated the effects of and reactions to its policies, as well as adopted violence as a tool to achieve its strategic goals, Iran's policies have generally been conceived with rational security objectives in mind.  The hypothetical development of a nuclear weapons capability would not fundamentally alter Iran's overriding foreign policy objective--regime security.

Iran's leaders, like those in other states, want to remain in power.  They want the regime in which they have invested and which serves their interests to endure.  Foreign policy, in addition to safeguarding Iran's borders and national integrity, is a means for safeguarding the regime.  Possession of a nuclear weapon will likely make Iran more impervious to attack and may make Iran bolder in its support for armed groups.  However, possessing a nuclear weapon will is not likely to alter Iran's paramount foreign policy goals of national and regime security.

Further, possession of a nuclear weapon is likely to cause Iran's isolation from the international community, an outcome Iran does not want.  Iran would therefore be likely to use any advantages of possessing a nuclear weapon in a way that would not significantly increase its international isolation even further.

The Islamic Republic is not an irrational or suicidal regime.  A nuclear weapon will not make it one.


Todd S. Sechser is an Assistant Professor of Politics at the University of Virginia and a Stanton Nuclear Security Fellow at the Council on Foreign Relations. For further information, read his op-ed coauthored with Matthew Fuhrmann, "Would a nuclear-armed Iran really be so dangerous?"

What could Iran achieve with a few nuclear weapons?  The historical record offers a clear answer: very little.

Pessimists worry that a nuclear Iran would be able to blackmail Israel, seize major oil fields, or force the United States out of the Middle East. But they ignore a key lesson of the nuclear age: nuclear weapons are not very useful for coercion. Israel, for example, did not suddenly acquire the ability to push around its neighbors when it obtained nuclear weapons. (If it had, it might have dissuaded Iran from pursuing nuclear weapons today.) Nor did China, North Korea, South Africa, or any other state that has ever built nuclear weapons. The reality is that nuclear weapons have never been very useful tools of blackmail.

The reason is that nuclear threats lack credibility. If Iran ever used nuclear weapons against one of its neighbors, it would suffer unprecedented international isolation, unify the region against it, and even trigger nuclear retaliation from the United States or Israel. Given these prospects, Iran's neighbors are likely to doubt whether its nuclear threats are actually sincere.

At best, nuclear weapons are credible tools of self-defense. But we need not worry that a nuclear Iran will wield vast new coercive leverage in the Middle East. In 1983, Robert McNamara observed that nuclear weapons "are totally useless - except only to deter one's opponent from using them." This lesson is worth remembering today.

This article originally appeared at CFR.org, an Atlantic partner site.