The Iranian nuclear challenge was transformed on President George W. Bush's watch. Events in Iran have advanced faster than the policy community's thinking about the problem. The brute fact is that Iran has crossed a threshold that is painful to acknowledge but impossible to ignore: It has lost its nuclear virginity.
Over the past eight years, the United States has insisted that Iran would never be allowed to develop the capability to enrich uranium, as that could be used to build a nuclear bomb. Three unanimous U.N. Security Council resolutions demanded that Iran "suspend all enrichment-related activities." That was a worthy aim. Technically, mastery of enrichment is the brightest red line short of nuclear weapons. Israelis have called it the "point of no return."
Bush chose the right operational objective when he declared, "We cannot allow the Iranians to have the capacity to enrich." Sadly, the strategy he pursued to prevent Iran from crossing that red line failed. One can debate whether a different strategy would have produced a different outcome. At this point, however, we must recognize the irreversible bottom line: Iran has demonstrably mastered the capability to manufacture and operate centrifuges to enrich uranium. The February report of the International Atomic Energy Agency documents the details: Iran is operating 4,000 centrifuges and has already produced more than a ton of low-enriched uranium -- an amount sufficient, after further enrichment, to make its first nuclear bomb.
The policy consequences of Iran having gotten this far down the road to a nuclear bomb are profound. These new facts require a fundamental reassessment not only of how we engage Iran but also of what we can realistically hope to achieve.
First, the long-held American objective to prevent Iran from acquiring the technical know-how to enrich uranium has been overtaken by events. While it was an appropriate goal at the time, Iran has acquired this capability. Its knowledge of how to enrich uranium cannot be erased. There is no realistic future in which Iran will not be "nuclear enrichment capable," that is, have the know-how to replicate its current enrichment facility at Natanz -- either overtly or covertly.
Second, the predominant focus of U.S. and international policy on Iran's observable nuclear enrichment facility at Natanz is largely misplaced. Preoccupation with the "known" to the neglect of the "known unknown" is common in policymaking. But at this point, it has become a caricature of the story of the drunk looking for his car keys under the lamppost, even though he knows he dropped them a hundred yards away, because that is where the light is. If Iran detonates a nuclear bomb in the next four years, the likelihood that the highly enriched uranium for that bomb will have been produced at Natanz is less than 10 percent. Thus, erasing Natanz today, either by Israel's threatened military attack or through negotiations, addresses the smaller part of the threat.
Further, and third, the source of the highly enriched uranium for Iran's bomb -- if Iran makes and tests a bomb during Obama's first term -- will be a covert enrichment plant that we have not discovered. By definition, we don't know the location or status of secret, undiscovered facilities. But as an American intelligence officer quipped, if Iran's nuclear project manager has put all his eggs in the one basket that is under the spotlight of international inspection, he should be fired.
The bottom line for American policy is that the menu of feasible options has shrunk. Every option available at this point requires living with an Iran that knows how to enrich uranium. Continued denial of this truth is self-delusion.
The central policy question becomes: What combination of arrangements, inside and outside Iran, has the best chance of persuading it to stop short of a nuclear bomb? More important than how many centrifuges Iran continues operating at Natanz is how transparent it will be about all of its nuclear activities, including the manufacture of centrifuges. Maximizing the likelihood that covert enrichment will be discovered is the best way to minimize the likelihood that it will be pursued. The best hope for defining a meaningful red line is to enshrine the Iranian supreme leader's affirmations that Iran will never acquire nuclear weapons in a solemn international agreement that commits Russia and China to join the United States in specific, devastating penalties for violation of that pledge.
The Obama administration cannot restore Iran's nuclear innocence. Its challenge is to prevent the birth of the next nuclear-weapons state.
Graham Allison, director of the Belfer Center for Science and International Affairs at Harvard's John F. Kennedy School of Government and the author of Nuclear Terrorism: The Ultimate Preventable Catastrophe.