More bluff and bluster, unless Iran is willing to drag their little tugboats through the sand to Syria and launch from there.
The Iranian Navy is little more than a coastal defense force, and once out of sight of Iran, couldn't fight their way out of a wet paper bag, even if the Chinese were selling them all the arms they could buy. They might TRY to hold off a choke point like the Strait of Hormuz, but they'd be telegraphing their move so far in advance that only the most dithering of leadership would fail to react in time.
Obama is C-in-C? Oh God, we're screwed.
But seriously, their only hope of closing off choke points would be mines (which Thor knows all too well) and MAYBE their Kilo boats, but they only have 3 at last count, and our 688's are getting awfully good at keeping track of them and their other coastal diesels. The Iranian Navy, for all the threat they pose to the Gulf, cannot project power like the US Navy can, and would get their asses kicked, much like the Russians did during the Battle of Tsushima...all that way to get your head handed to you. Yeah, I'm thinking not.