Pens that diplomats wield can be mightier than swords, but not necessarily because they destroy swords, much less the ability to make them. An agreement reached through diplomacy is a joint affirmation that it is in the parties' mutual interest to behave in certain ways and a joint commitment not to do other things they are capable of doing. Even a surrender by a belligerent defeated in warfare involves a forgoing of continued resistance that would be possible but costly to both sides. In short, international agreements are more a matter of intentions and motivations than of capabilities.
A failure to understand this infects discussion of the nuclear negotiations with Iran, and may have infected the U.S. negotiating position. There is a preoccupation with “breakout”—a scenario in which an Iran supposedly determined to violate an agreement suddenly races to build a nuclear weapon—and with stripping away Iranian capabilities in order to lengthen the time required under such a scenario for Iran to produce enough fissile material for a weapon. The fixation with breakout, with the repeated references to it as a supposed reason to be wary of any agreement with Iran, is misplaced for several reasons. One is that any conceivable agreement would entail a longer breakout time than without an agreement. That time already has been lengthened by the preliminary agreement reached last year, under which Iran has eliminated its stock of medium-enriched uranium and stopped making any more of it, as well as capping its supply of low-enriched uranium.
In any event, breakout time is immaterial when, under the extensive and unprecedented monitoring arrangements that will be a central feature of the agreement and a major reason for concluding it, any Iranian cheating in its use of permitted nuclear facilities would immediately be detected. As Greg Thielmann and Robert Wright have noted , whether breakout time is two months or six months or something else makes no difference when any U.S. or other foreign response to cheating, including a possible military response, could be mounted within a couple of weeks. If there were any prospect of Iran using clandestine, undeclared facilities to build a bomb—which is the way all past proliferators have made their bombs—this would be at least as much of a possibility without an agreement, and without the expanded inspections that go with it, than with an agreement.
The most fundamental reason the narrow focus on breakout is misplaced is that it disregards Iranian intentions and motivations. A successful agreement will be one that codifies a shared interest in an Iran whose nuclear program stays entirely peaceful and is a normal member of the community of nations, not subject to the debilitating economic sanctions that the United States has maintained at significant political and economic cost to itself. A successful agreement also will be one that each side, including Iran, will have strong motivation to maintain because it is clearly more in its interests than a breakdown of the agreement would be.
Largely missing from discussion of Iran breaking out of such an agreement is attention to whether Iran would have the incentive to do so. It would not. Doing so would subject Iran to far more disadvantageous conditions than it would have under an accord, without gaining any strategic advantage. A single nuclear device, or even a few, would serve no purpose for Iran when even the mere attempt to flaunt such a device for influence would imply willingness to escalate an issue to the nuclear level, and escalation would face the reality of vastly superior nuclear weapons arsenals owned by the countries Iran would most likely confront.
Cheating, or disavowing the agreement, would immediately—even before completing a single nuclear weapon—throw Iran back into the worst costs and consequences of being an international pariah, from which it has been working so hard to free itself. The U.S. Congress undoubtedly would enact, as fast as clerks could call the roll, anti-Iranian sanctions more severe than ever before. A military attack on Iran also would suddenly become much more likely than before. Those in the United States and Israel who have argued for an attack on grounds that negotiating with duplicitous Iranians is a mistake would now start winning the argument—and the Iranians are smart enough to realize that.
In short, breakout is a scary fantasy, but no more than that. It is a badly flawed standard for formulating a negotiating position or for evaluating a deal with Iran.
If the nuclear negotiations fail—or if Congress effectively destroys an agreement by interfering with its implementation—because of details about the number of centrifuges spinning or the number of months required to enrich uranium, this would be a major missed opportunity and an unwisely counterproductive pursuit of the objective of keeping the Iranian program peaceful. It also would be a destructively small-minded approach toward the use of diplomacy to pursue U.S. interests.