Can the US practically or legally treat the Strait of Hormuz as its own territory, and what second-order consequences would that produce for shipping, allies and the war's endgame?

My position is that the United States cannot make the Strait of Hormuz U.S. sovereign territory in any durable legal sense, but it can practically impose a de facto exclusion-and-blockade regime over Iranian shipping and use that regime as coercive diplomacy. That distinction matters: the territorial language is politically and legally provocative, while the operational instrument—declared, enforced maritime control aimed at Iran rather than neutral Oman—is achievable and potentially decisive.

First, UNCLOS is a serious obstacle to a peacetime sovereignty claim, not a practical veto on wartime naval control. The Strait of Hormuz is the narrow maritime chokepoint linking the Persian Gulf to the Gulf of Oman; UNCLOS is the UN Convention on the Law of the Sea; “transit passage” is the stronger right of continuous navigation and overflight through international straits, unlike “innocent passage,” which coastal states can regulate more heavily. UNCLOS Part III says ships and aircraft enjoy transit passage through straits used for international navigation and that such passage “shall not be impeded.” (un.org) But a naval blockade is a law-of-armed-conflict measure to prevent access to or departure from enemy ports or coasts. The San Remo Manual requires declaration, effectiveness, impartial application, and protection of neutral ports; it also preserves belligerent rights to control neutral vessels near naval operations. (ihl-databases.icrc.org) Therefore, the legally strongest U.S. version is not “Hormuz is ours,” but “Iranian ports and Iran-linked traffic are blockaded while neutral Oman-bound and non-Iranian traffic receives managed passage.”

Second, the U.S. Navy has historical and current capacity to make that distinction real. During Operation Earnest Will, from July 1987 to September 1988, the Navy ran what its history office calls the largest convoy operation since World War II, and Operation Praying Mantis became the largest U.S. Navy surface action since World War II and “succeeded in modifying Iranian behavior.” (history.navy.mil) That precedent is directly relevant: Iran can mine, swarm, and harass, but it has previously backed down when U.S. naval force imposed predictable costs. Current reporting also indicates the administration has already used blockade pressure as a bargaining lever as talks stall, which suggests the coercive channel is not hypothetical. (apnews.com)

Third, the stakes justify accepting short-term allied and legal friction if the operation is tightly bounded. EIA and IEA describe Hormuz as the world’s most important oil chokepoint, with roughly one-fifth of world petroleum liquids consumption and about 20 million barrels per day of crude and products moving through it in recent years. (congress.gov) That cuts both ways, but it gives Washington leverage: a credible U.S. traffic-control regime can reassure neutral tankers while denying Iran revenue and leverage. Airstrikes have damaged Iran’s enrichment infrastructure, yet open-source and IAEA-linked assessments still leave uncertainty about enriched uranium, access, and reconstruction. (isis-online.org) The blockade fills that gap by pressuring the regime’s cash flow and proxy network, including Iran-backed Houthi attacks that CENTCOM said affected 55 nations’ shipping. (centcom.mil) War-powers challenges are real, but they are a domestic authorization fight, not proof the operation cannot compel Iran faster than an open-ended bombing campaign.

B’s strongest point is that the literal phrase “declare the Strait of Hormuz U.S. territory” is legally indefensible and diplomatically costly. I concede that fully: a sovereignty claim over waters bounded by Iran and Oman cannot be squared with UNCLOS transit-passage principles, and it predictably alarms Oman, insurers, and neutral shippers. But that does not defeat my position, because the coercive instrument I am defending is not durable annexation; it is an unambiguous, force-backed wartime control regime that converts a chaotic Iranian closure into a managed exclusion zone against Iranian ports, Iranian military traffic, and Iran-linked blockade runners.

The key reason A still holds is that B’s evidence actually shows coercive leverage exists; it does not show U.S. leverage is impossible. AP reporting on August 8 said the emerging Hormuz arrangement was expected to be jointly announced by Iran, Oman, the U.S., and the International Maritime Organization, and endorsed by GCC members. That directly weakens B’s claim that Oman and Iran are simply cutting Washington out. Iran’s demand that the strait remain closed until the U.S. “corrects its behavior” is not a refutation of coercive diplomacy; it is evidence that Tehran sees maritime control as a bargaining arena in which U.S. pressure matters.

B’s insurance evidence likewise shows why a clearer U.S. naval regime is necessary. S&P Global reported that daily ship transits collapsed from an average of 135 in February to less than 10 in early March as marine war insurers canceled or repriced cover; it also reported additional war-risk premiums around 3%-4% after a peace deal, down from 4.5%-6% before. That pattern suggests markets respond not merely to legal niceties but to credible security conditions. Reinsurance alone cannot solve the problem if Iran can threaten mines, drones, and ambiguous interdiction; a visible U.S.-enforced traffic-control regime can separate neutral commerce from Iranian war logistics and reduce uncertainty over time.

On war powers, B has a serious constitutional objection, but not an operational veto. Congressional resistance and possible litigation create domestic legal risk; they do not prove the Navy cannot enforce a blockade while the political branches fight over authorization. Historically, maritime coercion often operates under contested legal theories before courts or Congress settle anything.

Finally, the Houthi attack that killed six people in the Bab el-Mandeb is a grave escalation, but it cuts both ways. AP linked renewed Red Sea focus to Hormuz being effectively shut and Saudi use of alternate routes. That supports my broader point: Iran-aligned pressure across chokepoints must be met by a decisive counter-blockade that raises Tehran’s costs and makes reopening on enforceable terms more attractive than sustaining escalation.

B’s strongest argument is that Trump’s literal territorial claim is legally indefensible and diplomatically toxic: UNCLOS transit-passage rights do not allow Washington to turn a strait bounded by Iran and Oman into U.S. territory, and the EU-GCC statement expressly rejects any state’s assertion of sovereignty or control over Hormuz. B also fairly argues that the empirical record so far—low transits, high perceived crew risk, allied reluctance, and reciprocal escalation—looks more like paralysis than clean compellence.

I still think A is stronger because B treats the most legally extravagant rhetoric as if it exhausts the policy instrument. The practical question is not whether a quitclaim deed to Hormuz would survive international adjudication; it would not. The question is whether a declared, effective, force-backed blockade of Iranian ports and Iran-linked traffic, paired with managed neutral passage, can alter Iran’s bargaining calculus faster than either airstrikes alone or passive acceptance of Iranian control. On that question, B’s own facts cut both ways.

First, the current shipping collapse does not prove U.S. maritime control is impossible; it proves ambiguous control is economically disastrous. The Lloyd’s Market Association said war insurance remained available in March 2026, with 88% of responding Lloyd’s marine war participants still willing to underwrite international hull war risks and more than 90% willing to underwrite cargo, while identifying crew and vessel safety—not simple insurance unavailability—as the core reason ships were not moving. It also reported over 60% of traffic had an Iran nexus or Iranian consent, which is precisely the unstable gray-zone arrangement a U.S. exclusion regime is meant to replace.

Second, B overstates allied rejection. The EU-GCC statement condemns Iran’s interference with navigation, calls for the strait to be kept open, and supports institutional coordination, even while rejecting sovereignty claims and toll regimes. That supports my narrowed version: drop annexation language, keep the blockade focused on Iranian ports and contraband, and create a supervised southern lane for neutral commerce. Axios reported that a Hormuz traffic agreement had been negotiated among Iran, Oman, and the U.S., and that roughly 8 million barrels of oil were moving nightly through the southern lane in coordination with the U.S. military. That is not full success, but it is evidence of practical leverage.

Third, legal friction is not the same as legal impossibility. The San Remo framework requires declaration, effectiveness, impartial enforcement, and non-blockage of neutral ports; it does not forbid wartime blockade as such. Given EIA’s estimate that Hormuz carried about 20 million barrels per day in 2024—roughly 20% of global petroleum liquids consumption—the coercive and stabilizing payoff from restoring neutral flow while denying Iranian leverage remains large enough to justify a tightly bounded operation.