Others argue that the optimal strategy is to constantly threaten a strike. The idea is to remind the Iranians that developing a nuclear capability carries risks, potentially forcing a change in their decision-making calculus. Such talk creates its own dilemmas. For one, it boosts oil prices, which blunts -- if it doesn't completely eliminate -- the cost of sanctions to the Iranian government. Constantly talking of war but not delivering one also undermines the credibility of the threat itself. It is also hard to control -- over time, the logic of an enduring and often-repeated threat leads to at least some conflict, with unpredictable results.
All told, there are many ways a military option could fail, and even more ways that its outcome would be impossible to judge. There is a better option. An Iranian nuclear program that has more intrusive inspections and narrower areas of uncertainty, as the International Atomic Energy Agency is reportedly seeking, puts the United States in a better position than it is in now. A precedent for this exists: Despite more than a decade of drama after the U.S.-led war on Iraq in 1991, the resulting inspections regime was enough to stymie any Iraqi nuclear ambitions. What was left was mostly smoke and mirrors and public relations, intended to bolster the regime rather than threaten its neighbors.
There is substantial international support for such an approach, ranging from governments who want to bolster multilateralism to those that fear a disruption in energy supplies. While Russia and China in particular seem reluctant to hand the United States a victory, these countries would prefer successful U.S.-led management of the crisis to chaotic conflict. One way the United States can sustain international unity is quietly to remind these states that it retains a war option, while doing everything possible to find diplomatic alternatives to it.
Such an outcome would fall in the uncomfortable middle ground between failure and success. Regional tensions would remain -- and some say they would remain intolerable. Iran would be an enduring problem that needed to be managed. For those seeking a "solution" to the Iran problem, it would count as a defeat.
Yet, achieving complete success is both unlikely and unverifiable. With no agreed starting point and no clear ending point in negotiations over Iran's nuclear program, and a host of contingencies in between, there seems little way to avoid at least some period of deeper uncertainty in efforts to change Iranian behavior.
Few view collective action as the most desirable course, or have much appetite for it. Over the next five to 10 years, however, being willing to accept half-victories is the key to preventing total failure in the quest to prevent Iran from acquiring the bomb.