The recent release of the National Intelligence Estimate that says that Iran is not pursuing nuclear weapons has been widely trumpeted as proof that we don't have to worry about it anymore. Why am I still concerned then? Oh yeah, that's right, look at the history of the Intelligence Community.
First, they were completely surprised at how far along Saddam was in 1991, Then they missed the Pakistanis development until they actually tested their nuke. After that, there was "Slam Dunk" Tenet, and his wonderfully incorrect failure. At the start of the Iraq war, a nuclear weapons program was found, in Libya, that the IC had no inkling of.
But I am sure that they have this one right. Right? I mean how often can they be so darned wrong and still be taken seriously? Of course, as shown at the link above, it is possible that this is just political chicanery, designed to make Bush look bad. Not that that has ever happened before. Snark!
It is also reasonable to question why the basis for the change was based on some notes from a meeting. Color me skeptical. It couldn't be part of any organized disinformation campaign could it?