Hormuz Is Not Closed Yet It Is Already a Weapon

The United States and Iran have not closed the Strait of Hormuz, though they have already turned it into a weapon, and the distinction matters because commercial paralysis can precede, and perhaps outlast, any formal blockade. Between 28 August and 11 September, the confrontation moved from disputed mine-clearance claims and conditional Iranian transit rules to reported US strikes on Larak and other IRGC infrastructure, Iranian missile activity towards Jordan, Bahrain, Kuwait and Iraq, and a maritime exchange involving US warships and Iranian-linked tankers. The existence of direct hostility is now very likely, albeit the sequence, damage and responsibility for individual incidents remain contested. Iran does not need to prevent every vessel from passing if it can make passage sufficiently hazardous that owners, insurers and crews decide against attempting it.

The commercial evidence points in that direction. Kpler recorded seven tracked Hormuz transits on 9 September against a recent 10-day average of 14, six commodity vessels on 8 September, and still lower counts on several preceding days; no LNG tanker was recorded leaving on 9 September. Those figures cannot be converted into a single exact decline, since the vessel categories, geographic boundaries and observation periods vary, while AIS gaps and delayed reporting obscure the total. Nevertheless, the direction is clear. Rystad reported oil flows below two million barrels per day against roughly eight to nine million before fighting resumed, although Vitol separately estimated that a shuttle arrangement was moving about ten million barrels per day through the wider Gulf of Oman system, a figure not independently verified. QatarEnergy extended force majeure into early November and cancelled 29 LNG cargoes. This is disruption, not closure; it is also far from normal commerce.

The United States has contributed to that ambiguity even as it seeks to overcome it. US Central Command reported escorting 40 commercial vessels carrying about 18 million barrels on 1 September and later said that 92 vessels had been redirected, while it also reported strikes on Iranian tankers near Kharg Island, Jask and the Gulf of Oman. The Iranian Revolutionary Guard Corps, meanwhile, claimed attacks on ten ships, and Jordan reported intercepting 18 of 20 missiles directed towards Al-Azraq, with no confirmed damage to the base. Neither side's account can be accepted wholesale. The United States may be protecting navigation while simultaneously enforcing a maritime campaign, and Iran may be threatening access without possessing the means to police every mile of the waterway. For shipowners, however, the distinction is less reassuring than it is for analysts. A tanker captain does not require proof of Iranian control before refusing the route.

There is a close historical precedent, though it should be used carefully. During the Iran-Iraq War, the Tanker War began in 1984, when both Baghdad and Tehran attacked commercial shipping associated with the other's oil exports. Kuwait sought protection by reflagging its tankers under the United States flag, and Operation Earnest Will began in July 1987, placing American warships alongside commercial convoys through the Gulf. The arrangement was presented as a means of preserving navigation, yet the convoy system itself became an instrument of escalation. On 24 July 1987, the reflagged Bridgeton struck a mine while leading a convoy, demonstrating that an apparently protected route could remain physically dangerous. On 14 April 1988, the USS Samuel B. Roberts hit an Iranian mine in the central Gulf, and the United States responded four days later with Operation Praying Mantis, destroying Iranian naval vessels and oil platforms. The episode did not produce a neat victory at sea. It produced a chain in which protection, interdiction and retaliation became difficult to separate, before Iran accepted a ceasefire on 20 August 1988.

The present crisis is not a repetition of 1987. There is no Iran-Iraq land war generating the same volume of maritime targets, and the current record does not establish a minefield, a formal convoy regime or a complete Iranian closure. Indeed, the Finland Prosperity has been observed carrying nearly two million barrels through Hormuz, selected crude movements continue, and the reported shuttle arrangement suggests that Gulf oil is not wholly immobilised. The stronger analogy lies elsewhere: once a state makes navigation contingent on military permission, escort, exceptional insurance or the tolerance of attack, the legal status of a waterway becomes less consequential than its perceived risk. The United States and Iran may each believe that limited maritime action strengthens their bargaining position. History suggests that limited action can instead create the circumstances in which a single mine, missile or mistaken identification demands a larger response.

The danger is compounded by the fact that Hormuz is now being discussed alongside Bab al-Mandab, even though the two theatres are not shown to be operationally coordinated. Houthi forces have reportedly pressed towards Mokha and the Hanish Islands, claimed maritime action against Saudi-linked shipping and attacked Abha, Khamis Mushait, Jazan and Najran; Saudi authorities reported at least 73 wounded in the wider campaign. Yet Bab al-Mandab recorded 28 commodity vessels on 9 September against a recent average of 27, and the supplied material does not independently confirm Houthi control of the positions said to overlook the strait. This is a meaningful distinction. The Red Sea route remains threatened, but it has not been demonstrated to be closed. Gulf exporters and Asian importers therefore face a particularly pernicious problem, since rerouting around the Cape of Good Hope may avoid one danger while lengthening voyages, raising freight costs and exposing vessels to another.

I would therefore hold that severe Hormuz restriction is very likely to persist through 21 September, while a complete operational closure remains unlikely and a durable US-Iran ceasefire remains unlikely. The most probable outcome is bounded retaliation, intermittent passage and continuing commercial avoidance, rather than either a clean diplomatic settlement or a total physical interdiction. I would change that judgement if independently tracked traffic returned for several consecutive days towards its matched pre-conflict baseline, if a written and enforceable navigation arrangement emerged, or if zero authorised commercial passage were confirmed across multiple independent systems for 48 hours. Until then, the decisive effect is not that Iran has closed Hormuz, nor that the United States has reopened it. It is that neither side needs to do either in order to make the strait economically unreliable. If uncertainty can perform the work of a blockade, what exactly does closure mean?