Second, Iranian hardliners may hope that chaotic oil markets -- with their attendant high gas prices hurting the American and European economies and U.S. Gulf allies becoming nervous -- might pressure Washington into ending the conflict even without securing Iranian concessions. Were that to happen, Tehran could conclude that U.S. military power is unable to stop it from doing as it pleases. Hardliners might see this as confirming Ayatollah Ruhollah Khomeini's saying, "The United States cannot do a damn thing." Continuing consultation with potentially nervous allies will be needed to counter this problem.
Justifying the Nuclear Program
A military conflict might also provide an opportunity for Iran to declare that the United States and Europe are hostile powers with which it cannot negotiate regarding the nuclear impasse, especially if European forces joined in the protection of shipping against Iranian attacks. Tehran could also claim that it needs a powerful deterrent against future U.S. or European action, namely, the capability to acquire nuclear arms in extreme circumstances if it exercised its claimed right to leave the Nonproliferation Treaty. If the United States were seen as the aggressor, that argument might win much sympathy around the world, possibly undermining the vigor with which UN sanctions were enforced. Hence the importance of emphasizing that Washington and its allies seek a diplomatic resolution to the nuclear impasse and have turned to sanctions only because Iran refuses to follow Security Council orders and engage directly with the United States.
Rallying the Nation
Some Iranian leaders might welcome war with America in the hope of rekindling the revolutionary spirit and rallying nationalist sentiment. As described above, the most important factor in predicting Iranian actions is the leadership's perceptions of what will happen, not what is actually most likely to occur. In fact, an Iranian public already unhappy at privations due to hardline policies could well blame their leaders for starting a conflict. Iranians have already gone through one protracted, bloody war under the Islamic Republic, and there are few indications they would welcome another, this time against any enemy much more powerful than Iraq.
Would the United States Lose or Would Both Sides Win?
Just because one side wins a war does not mean the other side loses. If both sides advance their political objectives, then both sides win. For the United States, a key test of any conflict with Iran is how it affects the nuclear impasse. In that sense, a war might work out well for the United States -- damage inflicted during the conflict could overcome Iran's factional infighting on the nuclear issue and force a dramatic reversal, as happened in 1989 to end the Iran-Iraq War. Yet war is a risky business, and naval conflicts could instead stiffen Tehran's resolve to acquire dangerous nuclear capabilities as quickly as possible in order to deter further U.S. attacks. In that case, further pressure might be needed to induce Iran to seek a diplomatic solution.
Nor is it clear what war would do to Iran's nuclear capabilities, as distinct from its intentions. In the event of a naval conflict in the Gulf, the United States might debate whether to attack Iran's nuclear facilities as well. If so, the challenge for the United States would be to ensure that such strikes significantly affect Iran's ability to reconstitute the nuclear program, and that the existing UN sanctions against dual-use items would hold after a strike.
Will War Come?
Because it is by no means clear that war with Iran would advance U.S. interests, Washington is unlikely to start a conflict except in the most dire circumstances. The more likely scenario is Iran inadvertently stepping over a U.S. red line, and Washington reacting more vigorously than Tehran expects. Much as the Korean War began in no small part because of mistaken North Korean and Soviet assumptions about U.S. red lines, so too might Iran blunder into a conflict with the United States.
Supreme Leader Ali Khamenei was cautious for years, but he has made several risky decisions of late, such as rigging the 2009 presidential election. In his view, refusing to compromise and hitting back hard were the keys to victory over the mass protests that followed the disputed vote. Over the past few months, Tehran has at times applied that same principle abroad: when slapped, slap back harder. For example, when Tehran plotted to kill the Saudi ambassador to Washington, it may have been responding to Riyadh's prior intervention in Bahrain, which had prevented Iran from aiding the island's Shiites. Afterward, the UN General Assembly voted 106 to 9 to remind Iran of its obligations to protect diplomats (not one Muslim-majority country stood with Tehran), while Britain and other countries imposed financial sanctions. Tehran responded by orchestrating the ransacking of the British embassy the next week. Both the assassination plot and the embassy attack hurt Iran's interests, but the regime ordered them anyway. That is not reassuring when considering whether Iran might attack in the Strait of Hormuz.
Indeed, the recent record suggests that Iranian leaders have become less cautious about taking aggressive gambles and more confident that the United States will not react. Washington should vigorously remind them how such over-optimism has repeatedly misled them. For example, they apparently -- and wrongly -- believed that the United States and Europe would not apply pressure against Iran's Central Bank, and that Europe would not boycott Iranian oil.
Tehran's chances of achieving its objectives through war presumably look much better if it can convincingly portray itself as the victim rather than the aggressor. Iranian officials may therefore do their best to paint U.S. and European actions as an attack that justifies a response. Tehran is less likely to carry out that threat if Western allies and Iran's neighbors vigorously counter the "victim" claim and loudly repeat their calls for engagement with Iran and negotiation of all outstanding differences.
For Washington's part, the proverb "if you want peace, prepare for war" holds true: the best prospect for persuading Khamenei to revert to his past cautiousness is to clearly lay out that the United States has red lines which, if crossed, will cost Iran dearly. Declaratory policy, such as President Obama's recent letter to Iran about red lines, helps. But Iran may be more impressed by deeds that back up those words. Peace is more likely to be preserved if the United States marshals its allies and demonstrates its power -- hopefully through military exercises alone, but also by vigorous response to any Iranian aggression if necessary.