It's been a while since I've quoted Fareed Zakaria but he's got a decent little piece on Iran that echoes many of my thoughts -

Dec. 6 issue - Anyone who tells you that he has a clear solution to the problem posed by Iran's nuclear ambitions is not being honest. It's about as tough as foreign-policy problems get. There are two basic approaches to prevent Iran from going nuclear: coercion and engagement. Both have serious flaws. But for either to have even a chance of working, the crucial player will not be America, but Europe.

..That's where Europe comes in. So far Tehran has not really borne much of a cost for its behavior. American sanctions have been toothless because the rest of the world eagerly trades with Iran.

...This might read like wishful thinking. It requires that Europe be united, bold and decisive. It requires the United States and Europe to coordinate policy closely. But look at what is happening in response to the fraud in Ukraine. Europe is united and has been tough. Washington and Europe are acting together. And if they persevere and refuse to legitimize the election results or deal with the new regime, they will prevail.

...There is a lesson here. Despite the surface clashes over the last two years, America and Europe have very similar visions of what kind of world they want. And when the two sides join forces, articulating their common ideals, interests and sense of historical destiny, the combined force is unstoppable.

I agree with Fareed's strategy prescription but I'm not as optimistic as he is about it's execution.   The Ukraine example demonstrats that occasionally, the the forces of Europe will marshall their Balls to deal with a quasi European nation on a quasi-diplomatic issue like an election.   I'm not so sure that these forces will stand so defiant in the face of the comparatively barbaric specter of a non-Western, nuke-armed, terrorist state.  Fingers crossed.

Zakaria is also correct that the "military option" isn't something that's quite so handy when dealing with Iran vs. Iraq.   Digging up a few stats on Iran vs. Iraq from the CIA World Fact book, we're forced to confront the fact that -

• Iran's population is 3x Iraq's
• Iran's per-capita GNP ix 3x Iraq's
• Iran's military is comparably far better equipped / resourced  (Iraq had been pounded in '91 and then continuously in Air operations;  Iran's been equipped domestically as well as via imports from other Arab nations, China, parts of Europe, etc.)
• Iran's nuclear sites are dispersed throughout the country including in some major population centers.  After Iraq's Osirak example, they're well aware of the benefits of a dispersed program.
• Unlike Iraq which had been a paraiah nation for over a decade, Iran enjoys active economic and political ties with key nations in Europe (the EU accounts for over 70% of Iran's trade volume)

In the end, military action against Iran is likely to cost far far more than 3x the cost of any operation against Iraq....  A generation or 2 ago, the prospect of a war that cost the US somewhere between 3,000 and 10,000 casualties in in exchange removed a nuclear tyrant might have been stomachable - I'm not so sure now.