Pakistan, Sept. 2 -- The latest exchange of fire between Washington and Tehran has revived the risk of a wider confrontation just as senior US military leaders warn that prolonged operations at the present scale are unsustainable. However, contrary to controversy-peddlers, the question confronting Washington is still nowhere near whether it can hurt Iran. It can. The harder question is what all that pressure is supposed to buy.

The economic results are stark. Iranian crude and condensate loadings fell to roughly 220,000 barrels a day in August, from about two million barrels a day in March. For about seven weeks, Iran has managed no meaningful crude exports through the Strait of Hormuz. Yet Tehran has not capitulated. Instead, the contes...