DUBAI, Aug. 28 -- Ten commodity vessels passed through the Strait of Hormuz on Wednesday. Before February, roughly twenty million barrels of oil crossed that passage every day. On Thursday night, the United States military declared it open.

Admiral Brad Cooper, the head of US Central Command, said in a video statement that "internationally recognized transit routes in the Strait are free of Iranian sea mines." Navy divers, special operations forces, and aircraft had spent months clearing the shipping lanes, a campaign Cooper called "challenging and dangerous," and guided nearly 1,500 commercial vessels carrying roughly 750 million barrels of crude destined for global markets.

The US declaration landed into a live dispute. Iran's Deputy ...