The dramatic revelation that Iran has a secret uranium-enrichment facility severely undermines one of Tehran's central talking points: that the West is denying Iran the its inherent right to peaceful nuclear power. This passage from Obama's remarks in Pittsburgh today goes to the heart of it:

 As the international community knows, this is not the first time that Iran has concealed information about its nuclear program.  Iran has a right to peaceful nuclear power that meets the energy needs of its people.  But the size and configuration of this facility is inconsistent with a peaceful program. 

In the wake of the Iraq WMD fiasco there have been some nagging doubts, though not terribly convincing ones, about whether the U.S. has been too quick to assume that Iran is up to nefarious things. This disclosure would seem to put those doubts to rest. But the net result still isn't clear. Without Russia and China wholeheartedly onboard, passing sanctions that will cause Iran to reverse course won't be easy.

Now Obama has given Iran two months before the U.N. sanctions push kicks in. I suspect the U.S. Congress won't be waiting that long to act unilaterally.