One of the sillier things that U.S. leaders have done over the past year or so is to formally reject a policy of "containment" or deterrence with respect to Iran. AIPAC pushed this position last year (in the form of a non-binding resolution sponsored by Senator Lindsay Graham), but even President Obama eventually had to go along. And then he sent Vice President Joe Biden to tell AIPAC that the U.S. wasn't bluffing.
Apart from pandering to the bomb Iran crowd, the apparent purpose behind such statements is to convince Iran that the United States simply couldn't live with an Iranian nuclear weapons capability and that they had better make damn sure they don't try to get one. Such rhetoric might make sense as a negotiating tactic -- though it's hardly guaranteed to work -- but it tells you exactly nothing about what the United States would or should do in the event that Iran one day crosses the nuclear weapons threshold. To see this, consider the following hypothetical.
Suppose there were a massive intelligence failure on the part of the IAEA and all of America's intelligence agencies and that Iran had a totally secret nuclear weapons development program. (This is precisely the scenario that hawks routinely warn about, by the way, especially whenever National Intelligence Estimates reach more optimistic conclusions). Suppose further that we got up one morning next week and discovered that Iran had successfully tested a nuclear bomb. And then suppose Iran provided us with additional information demonstrating that they had already manufactured a dozen more and that we had no idea where they were hidden. In short, imagine that the hawks' worst fears had all come true and that the Islamic Republic had become a nuclear weapons state overnight.
What do you suppose we would do? Would President Obama (or anyone else) immediately order a preventive war? Not on your life, because he could not be sure that Iran wouldn't find some way to get a bomb on American soil or use it against some close U.S. ally. Would Obama immediately announce a blockade or threaten an invasion, in order to persuade Iran to voluntarily give up its weapons? Hardly, because we couldn't put enough pressure on them to force compliance. Would the U.S. decide to abandon its regional allies and let Iran dominate the Persian Gulf? Of course not -- for the same reasons that it didn't abandon NATO when the Soviets tested a bomb in 1949 and it didn't abandon Japan and South Korea when China and North Korea tested nuclear weapons.
No, if Iran ever did cross the nuclear weapons threshold, the United States would do what it has always done when an adversary went nuclear: It would fall back on containment and deterrence. We would extend our far more potent nuclear umbrella over key regional allies, and we would send clear and unmistakable messages to Tehran about the dire consequences that would befall them if their new arsenal were ever used by anyone. Getting a bomb wouldn't transform Iran into a global superpower, and it certainly wouldn't allow them to blackmail their neighbors or launch a war of conquest. The only thing this situation would prevent the United States from doing is forcible regime change, which is something we shouldn't be contemplating in any case.
This situation would not be ideal, which is why I favor intelligent diplomacy that reduces Iran's incentive to acquire a deterrent. There are a number of good reasons why Tehran would prefer to stay on the safe side of the nuclear threshold, and there are a number of obvious ways that the United States could make that choice even more attractive, such as taking the threat of regime change "off-the-table." But declaring that Washington will never use containment or deterrence isn't credible, because these options are always there if we need them, and they make a lot more sense than the alternatives. In this regard the United States is bluffing, and the main risk is that they will feel compelled to follow through if the bluff gets called.
Alex Wong/Getty Images
Stephen M. Walt is the Robert and Renée Belfer professor of international relations at Harvard University.