Pentagon officials are trying to prepare for all of the ways Iran could retaliate, as President Trump hints at what he might do.

This has stoked speculation that Iran’s leadership may reach for another way to pressure its enemies to relent — blocking or effectively closing the Strait of Hormuz to shipping. This narrow waterway at the mouth of the Persian Gulf handles around a quarter of the world’s oil trade.

As the conflict escalates, container shipping faces growing risks from a potential chokepoint closure, rising insurance costs and surcharges from major carriers.