US Allies Develop Contingency Plan to Keep Strait of Hormuz Open Without US Involvement

On April 2, 2026, British Foreign Secretary Yvette Cooper convened a virtual meeting of more than 40 nations to plan the reopening of the Strait of Hormuz — the 21-mile-wide chokepoint between Iran and Oman through which roughly one-fifth of the world's oil and a fifth of its liquefied natural gas flows [1][2]. The United States was not at the table.

The meeting marked a culmination of weeks of diplomatic maneuvering that began when President Donald Trump told allies they should "take care of" the strait themselves, calling on countries that depend on Middle Eastern energy to "build up some delayed courage" rather than relying on American warships [3]. What started as a public rebuff of Trump's demands has since evolved into the most ambitious non-US maritime security operation attempted since the Cold War.

The Stakes: 20 Million Barrels a Day

The Strait of Hormuz is the single most consequential chokepoint in the global energy system. In 2024, an average of 20.3 million barrels per day of crude oil and petroleum products transited the strait — approximately 20% of global petroleum liquids consumption [2]. Saudi Arabia alone accounts for 38% of Hormuz crude flows, or 5.5 million barrels per day [2].

Source: EIA, World Oil Transit Chokepoints

Data as of Jan 1, 2025CSV

About one-fifth of global LNG trade — over 112 billion cubic meters in 2025, primarily from Qatar — also moves through Hormuz [4]. The asymmetry of who depends on these flows is stark: 84% of the crude oil passing through the strait heads to Asian markets [2].

Source: EIA

Data as of Dec 1, 2024CSV

Japan is the most exposed major economy. It relies on the Strait of Hormuz for approximately 90% of its oil imports and sources 87% of its total energy from fossil fuel imports [5][6]. South Korea gets about 70% of its crude from the Middle East, routing more than 95% of that through Hormuz, and sources 81% of its energy from imported fossil fuels [5][6]. Both countries hold limited strategic reserves — Japan roughly 4.4 million tons of LNG and South Korea about 3.5 million tons, enough for only two to four weeks of stable demand [5].

Europe is far less directly exposed. Only about 4% of crude flows through Hormuz are routed to European markets — roughly 600,000 barrels per day [2]. But European economies are not insulated: oil is a global commodity, and a Hormuz closure has driven WTI crude prices up 45.7% year-over-year to $104.69 per barrel as of late March 2026 [7].

Source: FRED / EIA

Data as of Mar 30, 2026CSV

How the Coalition Formed

The path from Trump's demand to a 40-nation coalition took less than three weeks.

On March 15, Trump called on China, France, Japan, South Korea, and the United Kingdom to dispatch warships to the Persian Gulf [3]. The response was swift and uniformly negative. British Prime Minister Keir Starmer rejected the request [8]. Japan said it had "not made any decisions whatsoever about dispatching escort ships" and was "continuing to examine what Japan can do independently and what can be done within the legal framework" [9]. Australia said it had not even been formally asked [9]. The European Union's Kaja Kallas reported there was "no appetite" for expanding the mandate of the EU's Red Sea naval force to cover Hormuz [10].

French President Emmanuel Macron was the most blunt. Attempting to secure the strait by force, he said, was "unrealistic" — "It would take forever, and would expose all those who go through the Strait to risks from the Revolutionary Guards but also ballistic missiles" [10].

Yet within four days, attitudes shifted. On March 19, the UK, France, Germany, Italy, the Netherlands, and Japan issued a joint statement from London condemning "attacks by Iran on unarmed commercial vessels in the Gulf" and the "de facto closure of the Strait of Hormuz by Iranian forces" [11]. The signatories expressed readiness "to contribute to appropriate efforts to ensure safe passage through the Strait" and welcomed coordinated releases of strategic petroleum reserves by the International Energy Agency [11].

The distinction the allies drew was between joining an American-led military campaign — which they rejected — and organizing their own collective response focused on demining, escort operations, and diplomatic pressure once active hostilities subsided. By April 2, the coalition had swelled to over 40 nations, spanning NATO allies, Gulf states including Bahrain and the UAE, and countries as geographically distant as Chile, Nigeria, and the Marshall Islands [1][12].

What the Allies Can Actually Deploy

The gap between what the coalition intends and what it can field remains the central question.

The US Fifth Fleet, headquartered at Naval Support Activity Bahrain, has historically maintained a force posture built around a carrier strike group, amphibious ready groups, and the 31st and 11th Marine Expeditionary Units [13]. The fleet's area of responsibility spans 2.5 million square miles across the Persian Gulf, Red Sea, Arabian Sea, and Indian Ocean [13]. Even with the US Navy's surface fleet having shrunk to roughly 100 major combatants from approximately 250 during the 1987–88 Tanker War era, a single Hormuz task force of 30 ships would represent nearly a third of today's US fleet [14].

Among allies, France has made the most substantial commitment. The French Navy deployed roughly half its fleet of major surface combatants to the Eastern Mediterranean, including the aircraft carrier Charles de Gaulle, and pledged 10 additional warships for Middle East operations, including potential Hormuz escorts [15][16]. The UK maintains a persistent naval presence in the Gulf through its base in Bahrain but has not committed specific additional assets beyond diplomatic leadership of the coalition.

The critical capability gap is mine countermeasures. Iran has reportedly laid mines across the strait, and any reopening operation would require extensive mine-clearing before commercial shipping could resume [17]. The US Navy itself has acknowledged limitations: as of early 2026, only one littoral combat ship with a mine countermeasures mission package was deployed to the region [14][18]. The UK, France, and several smaller European navies operate dedicated mine countermeasures vessels, but coordinating a multinational demining operation without US command infrastructure and logistics would be without precedent in the post-Cold War era.

Source: SIPRI / Global Firepower

Data as of Jan 1, 2025CSV

Iran's Denial Toolkit

Iran's ability to disrupt the strait draws on three decades of investment in what military planners call anti-access/area-denial (A2/AD) capabilities — systems designed to prevent an adversary from operating freely in a defined area.

The most immediate threat is mines. Iran maintains an estimated inventory of 5,000 to 6,000 naval mines, one of the largest stockpiles in the world [17][19]. The inventory includes contact mines, moored hull-impact mines, acoustic and magnetic influence mines, and limpet mines designed to attach directly to ship hulls [19]. These weapons are cheap, difficult to detect, and can be deployed from small boats, commercial vessels, or even fishing dhows with minimal warning.

Iran's anti-ship missile arsenal includes the Noor, a sea-skimming cruise missile with a range of approximately 120–170 km that can be launched from concealed coastal sites; the Qader, with a range of 200–300 km; and the Khalij Fars, a ballistic anti-ship missile with a 300 km range and an electro-optical seeker for terminal guidance against moving vessels [19]. These can be fired from mobile launchers positioned along Iran's 1,500 km Persian Gulf coastline.

The Islamic Revolutionary Guard Corps Navy (IRGCN) also fields swarms of small fast attack craft exceeding 50 knots, armed with light missiles, machine guns, or configured as explosive-laden suicide craft [19]. Combined with drone swarms and unmanned surface vessels, these forces are designed to overwhelm conventional naval defenses through sheer numbers rather than individual capability.

James Russell of the Naval Postgraduate School has argued that "cheap, unmanned anti-ship weapons reshape naval warfare" in ways that fundamentally challenge carrier-dominated power projection [20]. The cost-benefit calculus is unfavorable: defending a convoy against swarms of drones and fast boats requires expensive interceptors, while the attacking systems cost a fraction of the price.

How long Iran could sustain a full closure is debated. The IRGC's coastal defenses are formidable in the near term, but they are also vulnerable to sustained degradation through air and missile strikes. The question for the 40-nation coalition is whether they can mount such a campaign without US carrier aviation and Tomahawk cruise missiles — assets that have no equivalent among allied navies.

Legal Foundations and Historical Precedent

The coalition's legal footing rests on established international law. The Strait of Hormuz is classified as an international strait under the UN Convention on the Law of the Sea (UNCLOS), which guarantees the right of transit passage — free, continuous, and unobstructed passage for all ships and aircraft, both civilian and military [21]. The prevailing legal interpretation holds that transit passage rights cannot be suspended, even during armed conflict [21].

The most direct operational precedent is Operation Earnest Will (1987–88), in which the US Navy escorted reflagged Kuwaiti tankers through the Persian Gulf during the Iran-Iraq Tanker War [22]. Convoys of renamed Kuwaiti tankers would marshal in the Gulf of Oman, meet a flotilla of three to four US warships, and steam in company through Hormuz on a two- to three-day transit [22]. UN Security Council Resolution 598, adopted unanimously in July 1987, provided the diplomatic framework [22].

A more recent precedent is Operation Atalanta, the EU's counter-piracy naval mission off Somalia launched in 2008, which demonstrated that European navies could sustain independent maritime security operations over extended periods without US command authority. However, Atalanta operated against lightly armed pirates, not a state military with guided missiles and thousands of naval mines.

The current coalition is pursuing a UN Security Council resolution, drafted by Bahrain, that would authorize countries to use "all defensive means necessary" to secure the strait [1]. Whether Russia or China would veto such a resolution remains uncertain.

The Case for US Disengagement

The strongest argument for American withdrawal from Hormuz patrol duties runs roughly as follows: the United States is now the world's largest oil producer and a net energy exporter. Only about 3% of US crude oil imports transit the Strait of Hormuz. The primary beneficiaries of American naval protection are wealthy Gulf oil exporters and Asian importing economies — nations with the financial resources to provide their own security.

Saudi Arabia spent an estimated $78 billion on defense in 2025, approximately 7.1% of GDP [23]. The kingdom has embarked on the Saudi Naval Expansion Program II (SNEP-II), a multi-billion-dollar modernization of its Eastern Fleet that includes advanced frigate-sized warships modeled on the US Freedom-class Littoral Combat Ship [23]. The UAE secured over $2 billion in precision-guided munitions and military equipment in 2024 alone [23]. Saudi Arabia aims to produce 100% of its new naval vessels domestically by 2030 [23].

From this perspective, US taxpayer-funded Fifth Fleet operations amount to a subsidy for oil exporters who could finance their own protection. The $78 billion Saudi Arabia spends on defense annually dwarfs the budgets of most NATO members. If the Gulf states and Asian importers cannot collectively secure a 21-mile-wide waterway that their own economies depend on, the argument goes, then American protection has created a dependency rather than enhanced security.

US Energy Secretary Chris Wright reinforced this logic in late March, stating that Asian nations wanted to increase purchases of US oil and gas to reduce Middle East dependence — a shift that would diminish Hormuz's strategic significance for American energy security while creating export revenue [24].

Who Is Committed, Who Is Free-Riding

The April 2 coalition meeting revealed a familiar pattern in multilateral security: broad rhetorical commitment, narrow operational readiness.

France and the UK have taken the most concrete steps. France's deployment of 10 warships and its carrier strike group to the region represents a genuine force commitment [16]. The UK has assumed diplomatic leadership, hosting both the March 19 joint statement and the April 2 coalition meeting [11][1]. Germany, Italy, and the Netherlands signed the initial joint statement but have made no public commitments of naval assets [11].

Japan and South Korea — the two nations most economically vulnerable to a Hormuz closure — have been notably cautious. Despite signing the March 19 statement, Japan emphasized it was still "examining what can be done within the legal framework," a reference to the constitutional constraints on Japanese military deployments abroad [9]. South Korea joined the broader coalition but has not pledged specific forces.

Among Gulf states, Bahrain has been the most active, drafting the proposed UN Security Council resolution [1]. The UAE joined the coalition but has not detailed military contributions. Saudi Arabia, the state with the most at stake as the largest oil exporter through Hormuz, was not listed among the initial 40-plus coalition members — a conspicuous absence.

The coalition statement committed members to "the collective mobilisation of our full range of diplomatic and economic tools" [1] — language that pointedly avoids binding military commitments. Military planners from participating countries are scheduled to meet separately to develop operational plans, but no timeline for that meeting has been announced [12].

Command, Cost, and the Question of Infrastructure

If allied navies did assume Hormuz patrol duties, they would face three immediate structural problems: command authority, cost allocation, and logistics infrastructure.

No existing alliance framework has a ready mandate. NATO's area of responsibility does not extend to the Persian Gulf. The Combined Maritime Forces (CMF), a 39-nation naval partnership headquartered in Bahrain alongside the US Fifth Fleet, was built around American command and logistics. The Quad — the US, Japan, India, and Australia — is a diplomatic forum, not a military alliance. The EU's naval operations lack the scale and geographic reach required.

The operational cost of sustained Hormuz patrols is difficult to estimate precisely, but proxies exist. The UK's contribution to counter-piracy operations off Somalia ran roughly £30–40 million per year for a single frigate and support assets. A full Hormuz mission — involving mine countermeasures, air patrols, and convoy escorts — would be orders of magnitude larger. Analysts at the Washington Institute have noted that a task force of 30 ships would represent a significant share of any single nation's navy, implying annual costs in the billions of dollars per major contributing nation [14].

The logistical challenge may be the most daunting. The US Fifth Fleet's Bahrain headquarters was struck by Iranian missiles and drones on February 28, 2026 [13], raising questions about the viability of the existing support infrastructure. Allied navies would need to establish or share basing arrangements, supply chains, and intelligence-sharing protocols — systems that currently depend heavily on American infrastructure.

What Comes Next

The coalition's stated approach is sequential: first, wait for active hostilities to subside; second, clear mines from the strait; third, establish escort operations for commercial shipping [1][12]. Each phase carries its own risks and uncertainties.

The UN Security Council vote on Bahrain's resolution, which would authorize defensive measures to secure the strait, could provide the legal mandate the coalition seeks — or it could stall amid great-power vetoes [1]. Meanwhile, oil prices remain elevated, Japan and South Korea face tightening energy reserves, and the question of whether 40 nations can do what one superpower has done for decades remains unanswered.

The Hormuz coalition is, in one sense, precisely what American burden-sharing advocates have long demanded: allies stepping up to protect their own interests rather than relying on US military power. Whether it proves to be a functional security arrangement or a diplomatic exercise with insufficient military backing will depend on commitments that have not yet been made — in ships, money, and political will.