Pete Mansoor tells Tom Ricks he doesn’t think Iran would be able to withstand the international pressure not to close off the oil choke-point in the wake of an Israeli attack:
The Iranians need gasoline and other products too, and they would face an internal crisis alongside an international cudgel. Reaction would be swift for precisely the implications you cite. I see no chance that Iran — as we know it — could survive such an effort for any significant period of time. The Saudis would certainly sponsor foreign remedies for Persian perfidy (hmmm, almost sounds like an NDU war game title).
Maybe they wouldn’t be able to keep the strait closed. Mansoor’s pretty persuasive on that point, even for some reasons he doesn’t cite. You can imagine the Iranians giving certain flagged ships — hey, China, what’s happening — special access in exchange for international support. Put another way, an attack on Iran would generate lots of global sympathy for a regime that deserves absolutely none. The surest way Iran could squander that sympathy is by threatening the world’s oil.
That’s not to say that Iran wouldn’t miscalculate. All nations miscalculate. Non-state actors miscalculate. As human beings, we’re pretty bad at figuring out our long-term self-interests. Mansoor is making a point about international pressure forcing a course correction. But still, it’s possible that an Iranian overreaction to an attack would make it domestically difficult to reverse an early miscalculation on the Strait. Admittedly, this is less plausible on the surface than Mansoor’s other points, but since miscalculation so rarely gets factored into foreign affairs despite its ubiquity, I feel compelled to come to its defense.
Not that any of this is a good reason to attack Iran! The strong likelihood of a post-attack conflagration against U.S. interests in Iraq, Afghanistan and the broader Middle East compellingly militate against any such course of action.