Conflict between Israel and Iran has rekindled fears of a disruption to a narrow waterway key to the global economy. Skyscraper-sized tankers ferry roughly one-fifth of the world’s petroleum, as well as massive cargoes of natural gas,

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.

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