The United Nations report on Iran's nuclear program released last week should end the debate, if any debate remained, over whether Iran is moving toward acquiring the ability to build a nuclear weapon. In cautious but convincing detail, the U.N.'s International Atomic Energy Agency listed evidence that Iran is still conducting research that would lead to an atomic bomb, much of it in secret military laboratories. And Iran has refused to answer the U.N.'s questions or allow U.N. inspectors to see much of what it's doing, the easiest way to refute its critics' charges.
But the U.N. report didn't live up to its advance billing on other counts. It didn't say that Iran's leaders have made the decision to build a nuclear device; indeed, U.S. officials say they don't think Tehran's supreme leader, Ayatollah Ali Khamenei, has yet made that choice.
A year isn't a long time, but it's still a window of opportunity.
That's why the Obama administration's response to the U.N. report was so remarkably muted. There was no statement from the president, no news conference trumpeting a U.N. report that confirmed what the United States been charging for years. Instead, U.S. officials took pains to say that despite the chilling evidence of research on nuclear warheads and detonators, the glass is still half full.
"The IAEA report does not assert that Iran has resumed a full-scale nuclear weapons program," one senior official told reporters. Iran's current weapons research, he added, "appears to be relatively uncoordinated and sporadic."
In short, the White House message was this: There's no need yet for Israel or anyone else to go to war. There's still time for less drastic measures — diplomatic pressure, economic sanctions and covert sabotage — to persuade the Iranians to stop.
The administration's problem, however, is that its nonmilitary approach hasn't worked either. Iran rebuffed President Obama's initial, politically risky offer of "engagement." The administration succeeded in winning tougher economic sanctions from the U.N. Security Council, but enforcing the measures has been a long, hard slog. (China, which exports manufactured goods to Iran and imports oil in return, has been especially lax.) A covert campaign of sabotage waged by American, British and Israeli intelligence agencies against Iran's nuclear enterprises slowed uranium enrichment for a time but didn't stop it.
Administration officials insist that the sanctions and sabotage ("other measures," in their careful euphemism) are, in fact, working, just not quickly or decisively enough.
So now they propose to use the U.N. report as ammunition to push for tougher sanctions and tougher enforcement, especially by China and Russia. Russia has already rejected any new measures, but U.S. officials say they don't consider Moscow's initial reaction the last word on the subject.
The administration's hope is that as the economic and political costs to Iran increase, the Tehran government will find a way to back down or even, in a spillover from the "Arab Spring," collapse.
There's no sign that either of those happy endings is near. It's more likely that by 2013, after next year's election, whoever is president of the United States will face a stark and unpalatable choice: military action against Iran by Israeli or American forces, or acceptance of a nuclear-capable Tehran.
The drawbacks of military action will still be there. In the words of Defense Secretary Leon Panetta last week, "You've got to be careful of unintended consequences." There's no guarantee that a military strike would stop Iran's nuclear program, but it would almost certainly touch off a wider conflict, potentially including Iranian attacks on U.S. forces in the Persian Gulf, Iranian-sponsored terrorism and disruption in the world oil market.
But that doesn't mean it won't happen. Obama and all the likely Republican nominees for president have long said they consider a nuclear-capable Iran unacceptable. There's no wiggle room in that word; no president could back down from that warning without major damage to U.S. influence.
The issue is already part of the presidential campaign, with most of the Republican candidates criticizing Obama's approach as too weak. But their own policy prescriptions haven't been as different from Obama's as their rhetoric might suggest.
Former Massachusetts Gov. Mitt Romney, for example, wrote a column in the Wall Street Journal promising that "I won't let Iran get nukes."
Romney's prescription? Increase military aid to Israel and send more ships to the Persian Gulf to convince Iran that when the United States threatens to use force, it means it.
But his saber-rattling, like Obama's sanctions, is intended to avoid a war, not start one. "If you want peace, prepare for war," Romney wrote, citing a Latin proverb.
If the Iranians called his bluff, a President Romney would all too quickly face that same stark choice: go to war, or back down.
One purpose of good diplomacy, though, is to make sure presidents don't face bad choices. With more sanctions and more sabotage, the United States and its allies might just succeed in keeping Iran roughly where it is now — a year away from deploying a working nuclear weapon. That doesn't solve the problem; it merely buys time. But as one U.S. official involved in the policy likes to say: In this business, buying time is a form of success.