Military action is a last resort. But for nuclear diplomacy to succeed, Tehran must believe that if it tries to build a bomb, the United States will undertake military action to disrupt such an effort.
Iran's near-term nuclear intentions are unclear. The recent International Atomic Energy Agency report supports the conclusion that at the very least, Tehran seeks an option to build a bomb. Believing that its nuclear program would be attacked if it sought to exercise this option might deter it from doing so, or at least cause it to defer such a decision.
The recent alleged plot to assassinate the Saudi ambassador in Washington should be a wake-up call. It indicates that 30 years of Iranian terrorist attacks on American interests, without a U.S. military response, has convinced Tehran that it can continue to act with impunity—even on U.S. soil. Unless Washington alters Tehran's risk calculus, the United States may be targeted again. Iran may even conclude that it can also build a bomb with relative impunity.
Advocates of containment—the much-touted alternative to diplomacy or to preventive military action—often present it as a low-cost, low-risk policy option. They frequently gloss over the fact that to work, it must be backed up with a credible threat of force; that the costs of a nuclear deterrence failure in a proliferated Middle East may be measured in millions of lives lost; and that the likelihood of a nuclear deterrence failure is not trivial, given the propensity of an embattled, and increasingly insular and hard-line regime in Tehran, to miscalculate and overreach.
U.S. interests are best served by a diplomatic deal regarding Tehran's nuclear program, bolstered by a robust deterrent posture toward Iran. Paradoxically, to succeed diplomatically and to deter, the United States needs to be ready to use force in response to further acts of terrorism by Iran, or to an attempt by Iran to build a bomb. For the threat of force to work, however, it has to be credible, and it has to dramatically alter Iran's risk calculus. Right now, neither condition is present. The United States ignores this state of affairs at its own, and its allies' peril.
About Michael Eisenstadt Director of the Military and Security Studies Program at The Washington Institute for Near East Policy
Jamie M. Fly Former Director for Counterproliferation Strategy at the National Security Council
Matthew Duss Director of Middle East Progress at the Center for American Progress