CENTCOM confirmed the total naval blockade of the Strait of Hormuz begins Monday April 13 at 10am ET. Trump ordered the interception of “any and all ships entering or leaving” the strait, including those that paid tolls to Iran. Here’s the problem: the main vessels transiting Hormuz with Iranian permission have been Chinese oil tankers.

China is Iran’s largest oil buyer. Throughout the war, its tankers have crossed the strait under Iranian protection, paying in yuan directly to the Revolutionary Guard. Trump just ordered the interception of exactly those ships.

Experts warn this is the most dangerous point of the conflict. If the U.S. stops, boards or attacks a Chinese tanker, Beijing would have to respond. China already vetoed the UN resolution on Hormuz alongside Russia, is reportedly preparing to ship air-defense systems to Iran, and Trump already warned Beijing of “big problems.”

A U.S. Naval Institute analyst puts it this way: none of the options are clean. Escalating against China would drag the world into a conflict between its two largest powers. Not escalating means the blockade is just on paper.