Re: "...couldn't Iran stop the flow of oil through the Persian gulf?"
Of course.
But, the United States & other major powers could quickly open up the Persian Gulf.
Now...Iran, long before 9/11/2001, have each and every day declared publicly in their media that they were in the process of acquiring nuclear weapons and the means to deliver them, and have promised "before Allah" that they would attack and completely destroy Israel the very moment they had the capability, to be followed by their complete destruction of the United States of America.
Now that Iran is on the verge of completing its "holy mission" to annihilate all Christians and Jews, substituting in their place worldwide Islam under a Global Caliphate, and because they already have the capability to stop exports through the Persian Gulf, what do you think Iran is going to do once it has both the will, and also the capability, to literally annihilate all of Western Europe and the U.S.A?
Iran now is formally allied in military defense treaties with Syria, China, Russia, and Venezuela.
Either Iran is allowed, through acquisition of nuclear bombs and ballistic missiles, to control all Middle East oil including Saudi and Iraqi reserves, and is allowed to overthrow all other Middle Eastern governments replacing each with their own version of Islamism, acquiring the totality of world petro-wealth, followed by their quickly building up the most dangerous military force since the Third Reich...
...or Iran will be stopped dead in its tracks by the civilized world, with horrendous ramifications for the entire world, which by taking the risk and consequences now, will have been spared a far worse nightmare of unimaginable proportions which would follow our inaction.
Americans, Europeans, and Israelis should stop their worrying about "what if...?"..."but then...?"..."why should we be the ones...?", get off of our butts and show some maniacs that when we talk softly, we back it up with a bigger stick than they have.