Iran's an energy problem, not a security one.
Brendan Green makes an interesting case against a war with Iran, claiming that the problem is that it would succeed:
In sum, Tehran would have to reconstruct a program that took decades to build, from technology it could have serious trouble reproducing locally, in expansive facilities buried deep underground, while simultaneously making a major conventional effort to produce an IADS, all out of an economically struggling and generally impoverished resource base. A revived program could meet long delays and might never become viable....
The perception of success could reinforce Americaâ??s worst strategic tendencies. American statesmen will have strong incentives to increase the American military presence in the region in order to keep the Iranians from rebuilding their program. What is worse, Washington will have a new case study in the efficacy of American military power, one that appears to vindicate the broader policy of regional hegemony. Though speculative, evidence from the recent past supports the possibility of this sort of reaction.
I think this is close to the mark, but the real issue here is the timing of our judgments on what constitutes success.
I think Green makes a very convincing case that in the short-run, a U.S. military strike against Iran's nuclear facilities could do serious, long-lasting damage to their nuclear program, especially if post-strike pressure and technological embargoes on Iran were maintained. Iran can retaliate, possibly against U.S. civilian targets, but unless they're willing to risk an ever sharper confrontation, they would probably refrain from launching a 9/11-sized massacre on U.S. soil.
So any possible war with Iran would almost certainly be seen, initially, as a huge U.S. success.
But what about the longer term?
There is a very apt observation in David Ignatius' review of James Barr's A Line in the Sand: The Anglo-French Struggle for the Middle East 1914-1948:
The British and French were so eager for short-term advantage that they ignored the long-term problems they were creating.
Anyone familiar with the recent Mideast history appreciates that Britain and France created quite a few long term problems (which, curiously, Washington has taken upon itself to try and fix). This is a spirit that pervades our thinking in the Middle East. To the extent that Iran and its nuclear program posses a threat to U.S. security, it is the same threat that any potential hegemon in the Middle East could pose - using its strategic position to close down the free flow of oil to the outside world.
Seeing as any threat to blockade Hormuz is a double-edged sword, capable of doing more long-term harm to the wielder than the victim, it behooves everyone in the U.S. to take a deep breath and spend less time ruminating about sail barge nuclear attacks against the United States (!) and more about how to improve America's energy security over the long term.