How Trump’s Blockade of the Strait of Hormuz Works
April 16, 2026
Our business reporter Peter Eavis breaks down how American military ships have blocked Iranian-linked vessels from using the Strait of Hormuz as the U.S. encourages other vessels to make the passage.
The United States has implemented a naval blockade focused on Iranian ports, introducing a new and precarious phase to the six-week-old conflict that has roiled global energy markets. The operation, which began this week, involves the U.S. Navy interdicting commercial vessels destined for or departing from Iran. U.S. Central Command has clarified that the action is not a total closure of the strategic Strait of Hormuz. Instead, it is a targeted measure to prevent ships from accessing Iranian coastal areas while allowing passage for vessels transiting to and from other non-Iranian ports in the Gulf. U.S. naval forces have already begun enforcement, with reports of at least one Iranian-flagged cargo vessel being intercepted and turned back.
This American-led blockade is a direct response to Iran's own actions since late February. The crisis began after a U.S.-Israeli air campaign against Iran, which was followed by retaliatory missile and drone attacks by Tehran. Iran's Islamic Revolutionary Guard Corps (IRGC) then effectively shut down the strait, a chokepoint for roughly a fifth of the world's oil supply, by attacking merchant ships and reportedly laying sea mines. This move sent oil prices soaring above $100 per barrel and prompted major shipping firms to halt operations, causing a near-total collapse in traffic through the vital waterway.
The decision to implement the blockade followed the failure of high-stakes diplomatic talks in Islamabad. A temporary ceasefire agreed to on April 8 saw Iran begin charging exorbitant tolls of over $1 million per ship for passage. When subsequent negotiations led by U.S. Vice President JD Vance collapsed, President Donald Trump announced the U.S. would impose its own blockade. In addition to interdicting vessels, the U.S. Navy has also commenced risky mine-clearing operations to restore safe navigation. Guided-missile destroyers are providing protection for these efforts against potential Iranian attacks.
The economic consequences of the turmoil have been severe and widespread. The disruption has been described as the largest shock to global energy markets in history, triggering fears of a global recession. The International Monetary Fund has already revised its global growth forecast downward, citing the conflict as the primary cause. The price spikes are not limited to oil, with costs for liquefied natural gas, fertilizers, and other crucial commodities also surging, threatening to exacerbate global food insecurity and inflation. The cumulative global GDP loss from a sustained closure is projected to be in the trillions.
The blockade operates in a complex legal and diplomatic landscape. A naval blockade is considered an act of war under international law, and the U.S. action has drawn a mixed international response. China, a major purchaser of Iranian oil, has warned against the world reverting to "the law of the jungle." Key American allies, including the United Kingdom, have stated they will not support the blockade. Iran has condemned the move as an act of aggression, with military officials warning of dire consequences for any hostile forces in the strait. As U.S. warships patrol the Gulf, the world watches to see if this new strategy will force a resolution or push the region toward a wider, more devastating conflict.
Source: nytimes