On April 13, the U.S. military began a “blockade of all maritime traffic entering and exiting Iranian ports.” The move came after U.S. President Donald Trump announced on April 12 that the United States would begin a blockade after American and Iranian negotiators were unable to reach an agreement during a meeting in Islamabad.The announcement of a blockade immediately raised questions about how a blockade would work, how it fits into a broader U.S. strategy, its impacts on the global economy, and more. We asked five experts to assess the practicalities of enforcing a blockade, its legality, Iran’s likely response, and implications for China — and to offer some historical perspective.Read more below.Emma SalisburyNon-Resident Senior Fellow in the Foreign Policy Research Institute’s National Security ProgramAssociate Fellow at the Royal Navy Strategic Studies CentreWhile it is currently unclear what naval assets are being committed to enforce the blockade, the Strait of Hormuz is an extremely demanding operational environment for naval forces. At roughly 21 miles wide at its narrowest point, the strait is congested and bordered by the hostile territory of Iran, making enforcement of any blockade extraordinarily complex.To implement such a blockade, the U.S. Navy would need multilayered capabilities. Surface combatants — likely Arleigh Burke-class destroyers — would provide the visible presence, air defense, and interdiction capacity needed to enforce exclusion zones.Air superiority would be non-negotiable. Carrier air wings — including F/A-18 Super Hornets and E-2D Hawkeyes for airborne early warning — would need to operate continuously to suppress Iranian air and missile threats from the mainland, alongside Air Force assets.Persistent intelligence, surveillance, and reconnaissance via P-8 Poseidons and surveillance drones would be required to monitor the vessels transiting the strait, both to separate legitimate traffic from illegitimate traffic and to spot potential threats.Jennifer ParkerNon-Resident Fellow, Lowy InstituteAdjunct Professor, UWA