First, note a distinction made by former chief UN weapons inspector David Albright: Iran is more worried about being found in non-compliance with the Nuclear Non-Proliferation Treaty than it is with whatever the UN Security Council resolves. The former includes built-in punitive measures, and it is quite possible that Iran built this secret facility with an expansive interpretation of the NPT in mind. Second: there are roughly three levels of economic sanctions against Iran. Level one -- the least punitive -- would be to stop selling them gasoline, something they can't produce themselves. Level two -- a broader array of sanctions on other goods. Level three -- the world shuns Iran's key export -- oil. That would cripple their economy and produce significant suffering among the Iranian people. Here's betting that the U.S. is now working to build Russian and Chinese support for the tier-one sanctions. Finally, note the deadline for compliance set by French President Sarkozy: December. What happens if Iran does not allow full IAEA inspections by then? That was left unstated. Implicitly, the threat of military action by Israel (which, just between us, would make the Saudis and Egyptian leaders kind of happy, although they would pretend to be outraged) has been moved closer to the edge of the table. Still, there is every indication that President Obama wants to do everything he can to settle this dispute peacefully. He was briefed on this intelligence before he became president, and yet he still pursued a strategy of engagement. Iran's acknowledging something the U.S. already knew does not necessarily change the strategic calculus all that much. Indeed, Obama went out of his way this morning to stress that Iran still had a right to a "peaceful" nuclear energy program.

And is this really Obama's first "3 am" moment? Maybe not. The declaration by Iran comes at a great time for the US -- a time when the most powerful nations in the world have just expressed their resolve to punish NPT transgressors. Obama doesn't face a real hard decision here. In part because of the intelligence shared with Russia and China, sanctions are now seen as inevitable. President Obama's most difficult tasks are to figure out a way to ratchet up pressure without violating what he sees as the core premise of his diplomatic philosophy, to manage the (justifiable) triumphalism from Israel without encouraging them too much, and to communicate strength and resolve to the American people, who might well wonder why Obama has spent so much time trying to bring Iran to the table when it knew Iran was lying. What, precisely, does "engagement" mean now? The president's campaign promise to meet with Iran's leaders with "preconditions" is no longer operative.