Okay, so Iran is not currently developing nukes. Looks bad for our intelligence services, doesn't it, but that's no shocker, am I right? We sort of take that for the granted. Here's what the Iran news really does, however; it knocks Rudy Giuliani right out of the race.
Think about it. He's got some big negatives, in some ways combining the most negative aspects of both Bill Clinton and Bush the Younger. Giuliani is a pro-choice hawk with a penchant for keeping his fly open. He favors a generation of warfare to defeat Islamo-fascism and has been all over the map on gay marriage/union. His one abiding strength, however, has been as American's Mayor, America's Air Raid Warren, the man on the street with the bullhorn calling the all clear.
What propelled him into the future was clearly not domestic policy. Aside from the Republican boilerplate that all taxation is evil and the government is your enemy, he has no domestic policy. What he has is 9/11 and all future 9/11s. He was the guy to bump off Bin Laden and then knock on Ahmadinejad's door. But if they're not on the verge of nukes, then what the hell do we need Rudy for? He's been tarred with Bernie Kerik's very shmutzig brush and the good folks of Iowa will receive plenty of reminders that his second wife and children learned he was leaving their home forever via a televised news conference.
No, all he had was that bullhorn and the air raid helmet. I think the Iranians just pulled the magic carpet out from under him.