Nearly a fifth of the world's oil passes through the Strait of Hormuz. Iran could mine it within hours, and the US Navy no longer has the minesweepers to clear it quickly, so a handful of cheap mines could hold up tankers and oil markets for months.
The argument
Iran has already closed the strait without mines. Missile and boat attacks on at least 20 vessels since the war began pushed insurance rates high enough to keep most ships away.
The Islamic Revolutionary Guard Corps holds an estimated 5,000 to 6,000 naval mines, with facilities on both approaches to the strait. That is enough to seal it within hours.
“Iran doesn’t need to win a naval battle.”
Clearing them is the harder problem. With four of its minesweepers decommissioned, the US Navy now relies on littoral combat ships and helicopters, too few for a minefield on that scale. Clearing it could take months, with oil prices and insurance premiums climbing the whole time.
Tanker escorts and the six-country plan to reopen the strait do nothing about mines. That leaves striking the Iranian forces stationed near the strait, which US aircraft began doing the week this was published.
The mining reported on 12 March was most likely small and meant as a warning. Tehran is keeping heavier mining in reserve for the next escalation.
Iran's Mine Threat to the Strait of Hormuz