Interesting conclusion from an opinion piece attributing that view to former CIA director Woolsey:
[i]Iran produces about 4 million barrels of oil a day, most of which it exports. The country imports nearly all of its refined petroleum products – such as gasoline and diesel fuel – from Europe and India.
“And I think the thing that would bring the Iranian government and economy to its knees, quite quickly, would not be a cut-off of their exports of unrefined petroleum (but to ban) their imports of refined petroleum products,” Woolsey said. [/i]