Elbridge Colby and Austin Long write: The pressure for an attack on Iran is building. Media reports suggest that the Obama administration is under pressure to take action and may even be considering action itself, and Foreign Affairs published an article in its opening 2012 issue by nuclear expert Matthew Kroenig forthrightly stating that it is “time to attack Iran.” Many argue that strikes against Iran’s nuclear program are the only responsible course. Defense Secretary Leon Panetta declared on December 18 that if the United States receives “intelligence that [the Iranians] are proceeding with developing a nuclear weapon, then we will take whatever steps necessary to stop it.” And former White House Middle East chief Dennis Ross suggested in a December 23 op-ed that, if pressure fails, the military option is the only sensible recourse. The United States cannot live with a nuclear Iran, he argues.

The reality, however, is that attacking Iran without provocation is a dangerous course. The arguments for avoiding military strikes are well known: deterrence, while neither easy nor cheap, can work; the costs of likely Iranian retaliation outweigh the likely benefits, perhaps markedly; and the United States (and its allies) have considered preventive attacks against adversary nuclear programs before, thought the better of it and come out tolerably.

But perhaps the most important argument against attacking Iran has received less attention. That is that none of the attack proponents can give a sensible answer to the question General David Petraeus posed at the beginning of the Iraq war: “How does this end?” Kroenig and other advocates for war note, correctly, that a strike against Iran could do substantial damage to Iran’s program. But they fail to explain how the United States will prevent Iran from simply restarting its program, this time in deadly earnest. Moreover, they don’t explain why such strikes won’t contribute to the immediate rallying of the Iranian people around the otherwise reviled regime.