‘Safe passage’: The fatal ambiguity at the heart of the Hormuz MoU

Its promise of safe passage settled neither who governs the strait nor on what terms, making renewed escalation the memorandum’s logical outcome.Chair of Maritime Law at City St Georges, University of London.Published On 16 Jul 2026Barely three weeks into a Memorandum of Understanding (MoU) meant to end a war, the United States is once again blockading Iranian ports, the two states are trading strikes on bases and military assets across the Gulf, and Mr Trump has floated the idea of charging shipping a 20 percent levy, or “protection money” in less polite language, for the security of the Strait of Hormuz. I would argue, however, that this is not so much the collapse of the June deal, as many are saying, as its logical conclusion. The clause on which global oil traffic depends was written to be signed, not to be operated, and the water is now exposing the difference.Article 5 of the MoU promises “safe passage of commercial vessels” through the strait. It is an elegant phrase. It is also, as a matter of Maritime Law, almost empty, and that emptiness is less an accident of drafting than the price of agreement. Iran and Washington could sign because the words commit each side to very little and permit each to believe very different things. That is precisely why the arrangement is unravelling faster than even the pessimists expected.Consider what “safe passage” leaves unanswered. It does not say who administers it. Article 5 tasks Iran with making “arrangements using its best efforts”, then sends Tehran off to hold a “dialogue” with Oman and “discussions” with the other Gulf states to define “the future administration and maritime services” of the strait. The US, the world’s pre-eminent naval power and the historical guarantor of navigational freedom, is not a party to those talks. Nor is the arrangement conditioned on the parties reaching any agreement. Iran is therefore free to argue that, once it has talked, it may unilaterally announce a new regime: Prior notification, designated Iranian corridors and charges dressed up as fees for “security, safety and environmental services”. Reports since the signing put the revenue Tehran imagines at tens of billions of dollars a year. An arrangement meant to reopen the strait has instead handed one coastal state a colourable claim to metre it.