The two-week ceasefire agreed by the United States (U.S.) and Iran on April 8th signalled a productive effort in halting suffering in the Middle East. While ceasing hostilities in Iran, the U.S. did not abandon its offensive campaign, diverting its attention towards disrupting Iran’s most indispensable economic branch.
The Operationalization of the U.S. Blockade
With this endeavour, the U.S. is employing more than a dozen warships, over 100 aircraft, and more than 10,000 personnel close to the tumultuous Strait of Hormuz, restricted by Iranian authorities in response to U.S. and Israeli actions. The U.S. Central Command (CENTCOM) clarifies the exercise, noting that the blockade encompasses all Iranian ports, both inside and outside the Strait of Hormuz, but not the chokepoint itself, implying that traffic unrelated to any Iranian port is not intercepted.
Enforcing the blockade ultimately entails that ships sailing towards or out of Iranian ports will be turned around, in order to avoid any seizures of vessels. The U.S. military has hinted that its fleet will be stationed east of the Strait, in the Gulf of Oman and Arabian Sea, pivotal transit waters for most of Iran’s exports.
International law advocates criticized the operation, stressing no country has a legal right to block shipping in straits used for international transport; the UN maritime agency’s Secretary-General Arsenio Dominguez claims “there is no legal basis in international law to block any strait used for international navigation”, whilst still acknowledging the conflict and its belligerents.
The latter is what fuels the argument that the operation is lawful: “the US, as a belligerent, can legitimately impose a blockade under international law – specifically, the law of naval warfare” clarifies Donald Rothwell, professor of international law at the Australian National University. Moreover, CENTCOM recognizes that blockading an international waterway is illegal under maritime law, thus the blockade acts as an interdiction of cargo-carrying ships into or out of Iran rather than a suppression of the strait itself.
Is the blockade truly enforced?
The phenomenon’s accomplishment has come under scrutiny given reports of various oil tankers crossing in or out of Iranian ports ever since the Americans’ proclamation.
Among the most notable cases are the tankers Rich Starry and Elpis, both of which were tracked departing Iranian terminals and moving through the Strait of Hormuz in the days following the blockade’s implementation. According to ship-tracking data, the Malawi-flagged Rich Starry appeared to successfully exit the Gulf despite the U.S. naval presence, raising immediate questions about the consistency of enforcement.
Similarly, the Elpis “shadow fleet” has reportedly traversed the strait despite the active U.S. siege, commencing its journey out of the Iranian port of Bushehr. Initial media perception pointed to the Americans’ unpreparedness in employing the blockade as the reason behind the ship’s placid departure from Iran and through the Strait of Hormuz.
Yet these apparent “successes” at bypassing the American stoppage mask a more complex operational picture. The U.S. position remains that the blockade is effective: CENTCOM reports indicate that multiple vessels – at least a dozen in the first days – were warned and turned back before completing their journeys. Rather than physically seizing ships at the Strait, U.S. forces have adopted a layered enforcement approach, allowing vessels to move initially before intercepting them further east, particularly in the Gulf of Oman.
This enforcement strategy helps explain how tankers such as Rich Starry and Elpis could be observed transiting the Strait without necessarily constituting a breach. Passage through Hormuz alone does not violate the blockade; what matters is whether ships ultimately succeed in delivering Iranian cargo to international markets.
Indeed, rumours suggest that the two U.S.-sanctioned ships have not been allowed to complete their commercial endeavours with Iran. The most revealing evidence is that tracking services were unable to trace the two ships closely after passing through the Strait of Hormuz, an indication that they might have been headed off by the Americans.
The Aftermath: Economic Impasse & Retaliation
Beyond the utter maritime ambiguity, the reality of the blockade yields drastic economic consequences. Oil exports remain the backbone of the Iranian economy, and such disruption, materialized through delayed shipments, rerouted tankers, or heightened insurance and transit costs, translates into significant fiscal strain. The uncertainty in maritime access has already begun to ripple through Iran’s export capacity, with traders and intermediaries facing growing risks in handling Iranian crude.
This pressuring campaign has generated satisfactory outcomes for the American administration, with Iran declaring the Strait “completely open” for all commercial vessels. While the announcement was mostly a testimony of the fruitful peace discussions between the U.S. and Iran, along with further commitment to a ceasefire in Lebanon, the timing of the pronouncement still suggests the blockade was an efficacious tool in dwindling Iran’s economic flow.
Nonetheless, the Americans’ contentment did not last too long, with Iran announcing on April 18th, only a day after the aforementioned constructive step, that it would close the Strait once again. Thus, Iran faces a strategic dilemma: to reopen and stabilize access to the strait in order to preserve what remains of its export flows, or to continue leveraging disruption as a tool of pressure against the United States and its allies. Ultimately, the blockade has transformed the Strait of Hormuz into more than a chokepoint; it is now a contested space where law, strategy, and economic survival intersect.
Featured photo above is of The San Antonio-class amphibious transport dock ship USS New York and the Arleigh Burke-class guided missile destroyer USS Porter transiting the Strait of Hormuz. This file is a work of a sailor or employee of the U.S. Navy, taken or made as part of that person’s official duties. As a work of the U.S. federal government, it is in the public domain in the United States.
