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Policy Analysis

PolicyWatch 1387

Thinking about Preventative Military Action against Iran

Patrick Clawson and Michael Eisenstadt

Also available in العربية

Policy #1387

July 1, 2008

On June 20, 2008, Michael Eisenstadt and Patrick Clawson addressed a Policy Forum at The Washington Institute. Mr. Eisenstadt is a senior fellow and director of the Institute's Military and Security Studies Program, and Dr. Clawson is deputy director of research at the Institute. The two recently coauthored The Last Resort: Consequences of Preventive Military Action against Iran. The following is a rapporteur's summary of their remarks.


When considering preventive military action against Iran's nuclear program, one must remember that such an exercise is purely hypothetical at this point. In fact, with some renewed vigor, diplomacy still might succeed in convincing Iran to suspend its nuclear program, as was the case in 2003.

Context matters when discussing preventive action against Iran. For example, if Iran's leaders announced they were developing nuclear weapons, leaving the Non-Proliferation Treaty (NPT), and intending to test a nuclear weapon, the debate for using preventive military force would be entirely different. There is still a debate in the analytical community whether Iran wants a nuclear weapon or just a rapid breakout capability. Iran's Supreme Leader Ali Khamenei has stated that Iran has no intention of acquiring nuclear weapons and that their use is un-Islamic.

If Iran suddenly announced its intent to test a nuclear weapon -- voiding the statements of the past twenty-five years -- such a situation would cast grave doubts on previous assessments and force analysts to seriously reconsider how well they can predict future Iranian action. If Iran persists on the path of nuclear weapons development, the resulting international crisis would surely change the discourse over preventive military action. The use of preventive military force, in this and other cases, would become thinkable.

Several other factors make a difference in the context of the use of force. In domestic Iranian politics, the extent to which the country is led by hardliners, who are seen by their own people as risk-takers, overly assertive, and overly confident, creates one context. In contrast, if Iran were to elect a new president who is seen as a man of moderation and compromise, such a situation would create a very different context in Iran, internationally, and in the United States. Similarly, developments on the international diplomatic front would affect the context.

An additional key issue is on what basis a determination is made about the status of Iran's nuclear program. The U.S. intelligence community has a decidedly mixed record on this score. The International Atomic Energy Agency (IAEA), on the other hand, has done some remarkable detective work during its on-site inspections in North Korea, Iraq, and Iran. Therefore, a decision to use preventive military force based on IAEA inspections would be very different than acting on disputed intelligence.

The level of support for military action will determine what happens after the operation, and is also an important metric in determining the success of such a strike. Success would also weigh on domestic U.S. and international support for, and Iranian domestic rejection or acceptance of, military action. Iran, based on its record, is sensitive to world opinion, and this should not be discounted when considering diplomatic pressure in resolving the issue. The impact of a strike on global U.S. standing will also be a key determinant in the success or failure of military action. A strike on an Iranian nuclear facility would have the added objective of dissuading other international actors from pursuing nuclear arms.


Assessing the risks and outcomes of preventive military action against Iran is a difficult analytical challenge to undertake because of the military and political uncertainties, and the high stakes involved. Diplomacy is by far the best option right now, at least as long as it offers even a mild chance of success.

Nevertheless, the United States might come to the conclusion soon that diplomacy has run its course and that other options, namely prevention and deterrence, have to be examined. Prevention must remain as an option in order to bolster diplomacy, and because it may be necessary at some point. The public debate about prevention tends to focus on military and technical challenges. On the issue of targeting, accurate intelligence is the sine qua non for effective prevention. There are also the challenges of weaponeering and hitting hardened, buried facilities effectively. Success most likely would require multiple strikes over time.

To measure the success of such a policy, the most crucial factor is whether Iran decides to rebuild. Success would likely hinge on Washington's ability to craft a sustainable policy that effectively integrates military, diplomatic, and informational policy instruments to cause maximum destruction to the nuclear infrastructure, to mitigate the consequences of Iranian retaliation, and to set the conditions for successful post-strike diplomacy or military action. Iran's possible responses, though not exhaustive, include: withholding its oil exports, disrupting regional oil exports, attacking allied and U.S. regional assets and interests, or launching a full-scale war.

Prevention cannot be examined in a vacuum, however, and must be considered alongside the other policy option available to the United States, namely deterrence. The cost-benefit analysis of the two options may be one of the most complex and difficult problems facing the United States, given the uncertainties of success and the prices of failure for each. Deterrence is not an easy, low-risk alternative. If one were to juxtapose the risks and benefits of the two options, the balance sheet might conclude that prevention entails significant near-term risk of Iranian retaliation for an uncertain outcome whose benefits may be relatively short-lived, while deterrence defers the crisis but runs very high risks in the long term. There is also the risk that Iran's acquisition of nuclear capability may tempt other countries in the Middle East and elsewhere to pursue their own nuclear capability.

Prevention and deterrence are not mutually exclusive options. Prevention may delay but not halt Iran's nuclear program, and may in the end be just a very costly detour on the path to deterrence. Given that the United States has set a very high rhetorical bar with Iran's nuclear program, if Tehran acquired a nuclear weapon, the United States might have more difficulty establishing credible future warnings, threats, and red lines.

If diplomacy fails, either option will have profound consequences for the future of the Middle East, the international nuclear nonproliferation regime, and for U.S. standing in the world. For this reason, the United States must redouble its efforts to find a diplomatic solution to this problem.

This rapporteur's summary was prepared by Audrey Flake.