Why Is It So Difficult to Reopen the Strait of Hormuz? | Asked & Answered

Why It Matters

The closure has triggered one of the most severe recent oil-supply disruptions, exposing a strategic vulnerability in global energy transit and forcing the U.S. to weigh a risky, costly military campaign or prolonged economic and market instability. It also highlights allied reluctance to be drawn into direct conflict, complicating coalition responses.

Summary

Iran’s blockade of the Strait of Hormuz has proven resilient because Tehran has used asymmetric tools—mines, drones and speedboats—to control a 100-mile waterway that narrows to 21 miles, effectively denying passage without a conventional navy. Reopening the strait would require a major military operation: mine-sweeping under fire, destroyer escorts for tankers, air cover to counter drones, and potentially seizures of offshore islands, with inevitable casualties. U.S. forces were reportedly unprepared for this scenario, having reduced mine-countermeasure capacity and relying on reluctant allies for sweeping support. The difficulty of locating and clearing mines while under attack helps explain why the blockade has persisted despite damage to Iran’s military.

Original Description

The continued blockade of the Strait of Hormuz has triggered the most severe oil supply disruption in recent history, placing immense pressure on the U.S. to reopen the Strait. Why has reopening the strait proven so difficult? We turned to CSIS expert Mark Cancian for answers.