For decades, Iran has held the Strait of Hormuz as its trump card in reserve. And now, they have played it.
The 21-mile-wide choke point – through which 20 per cent of the world’s oil supplies flow – provides the perfect leverage for a regime that believes America and Israel’s onslaught can be brought to an end by imposing massive, retaliatory economic pain.
With each day that the Strait remains effectively blocked, the costs to America and the world mount. Donald Trump has appealed to Nato and even China to help reopen it. But how could that be done?
The sea
The most immediate solution – and from a military point of view, the simplest – would be a naval escort mission backed by immense air power.
“The US will be going through a number of stages as it tries to reopen the Strait. The first is to degrade Iran’s ability to launch anti-ship cruise missiles and deploy other capabilities, like small boats, in the Strait by using intelligence to identify where they are based and then striking them,” says Jack Watling, senior research fellow for land warfare at the Royal United Services Institute (RUSI).
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“Normally, you would also be trying to degrade the sensors that would be used to track tankers [before they are attacked]. But because this is a very enclosed waterway, that really can’t be done. There are just a lot of people who can directly overlook the Strait.
“And so the second element will need to be the escorting or convoying of ships through the Strait at some point, and therefore, naval vessels providing direct protection to shipping as it tries to get through. Which is what Trump has asked for, some kind of assistance in that respect.”
Trump last week expressed the hope that “China, France, Japan, South Korea, the UK and others, that are affected by this artificial constraint, will send ships” to unblock the Strait. But offers of help have not been forthcoming. Keir Starmer said on Monday that Britain was working with allies on a “viable plan” to help, but would not be drawn on sending ships. Others, including Germany, France and Japan, have also refused to offer immediate assistance.
That’s a problem for Trump and his advisers, who were apparently caught by surprise when Iran began hitting ships in the Strait of Hormuz, possibly because Tehran refrained from closing it during last summer’s 12-day war. As a result, the resources required to keep it open were not available when the war began, even though the US Navy had war-gamed for this exact scenario for decades.
Success now will require rushing in the right assets to counter a range of Iranian threats.
“You have to contain threats in three environments: air, surface and subsurface,” says Tom Sharpe, a former Royal Navy commander who sailed warships through the Strait during his career. “You can’t even consider going in there until you have a decent level of assurance that those three are at least under control. Once you have done that, you can consider conducting escort operations.”
First, the Americans must assemble a force capable of combating drones and anti-ship missiles in the air, fast attack boats and unmanned surface drones, on the surface, and mini-submarines and mines beneath the waves. Then, there are two basic options for shepherding vessels through the Strait. The first, familiar from the Battle of the Atlantic, is to group cargo ships into convoys accompanied by warships that can engage and see off enemy threats.
Americans have done this before. “Operation Earnest Will”, the largest convoy operation since the Second World War, saw US warships protecting Kuwaiti and other tankers transiting the Strait of Hormuz from Iranian attack in the latter stages of the Iran-Iraq war.
The second strategy would see the US deploy warships to patrol overlapping “missile boxes” that linked up to form a protective chain between the Iranian coast and commercial shipping lanes. That was the approach they used in “Operation Prosperity Guardian”, the 2023 to 2025 effort to protect Red Sea shipping from attacks by the Houthis in Yemen.
“Ideally, you’d want a mix of both,” says Sharpe. “But if you consider those three threat environments [air, surface and subsurface], and the fact that you need to escort 100 ships a day to restore shipping to normal levels, you’ve got a resource problem.”
At its peak, “Operation Earnest Will” involved 30 American warships – and because shipping volumes were lower in the 1980s, they were protecting fewer ships.
“Operation Prosperity Guardian” involved between six and 12 destroyers at various times, but only had to worry about threats from the air because the Houthis did not have fast attack boats, submarines or mines.
As it stands, the US has two carrier strike groups in the region, but they are currently preoccupied with prosecuting the air war against Iran. One of the carriers, USS Gerald R Ford, is expected to put into port in Crete after a major fire on board, US officials said on Tuesday.
The carrier has already been at sea for nine months, having taken part in operations against Venezuela in the Caribbean prior to arriving in the Middle East, raising questions about crew fatigue and morale. Hence Trump’s appeals to allies and adversaries alike to lend a hand.
Among those he has called on to help, the Royal Navy still has a handful of minesweepers, but they are all in the UK and would take weeks to reach the Gulf. Britain is also one of the leading pioneers in the use of subsurface anti-mine drones – essentially torpedoes loaded with cameras and hi-tech sensors that can map the seabed and locate mines and other threats. But the technology is still in the experimental phase and has not yet been used in combat.
China, meanwhile, which has long ignored international sanctions on the purchase of Iranian oil and buys up more than 80 per cent of all such exports, has the largest navy in the world. But so far, it does not seem to feel that the pressure of the blockade is critical enough to send its own ships to unblock it.
Indeed, the Iranian attacks to date have been selective. While they have struck every couple of days to deter shipping, Iranian forces have also allowed vessels carrying their own crude to sail unmolested to customers, including India and China.
The land
Operations at sea may not be enough, which is why America’s 31st Marine Expeditionary Unit (MEU) is on its way from the Western Pacific to the Middle East. With 2,500 marines, amphibious assault ships, landing craft, helicopters and MV-22 Ospreys – a vertical take-off aircraft designed for amphibious landings – they will provide US commanders with a powerful raiding force that could take the fight onshore.
Their presence alone, on board American vessels, could shape the battle.
“They can have an effect without putting a boot on the ground,” says Vice Admiral Andrew Burns, a former commander of the Royal Navy’s amphibious task group. “Just posting them off the coast of Iran is going to have a cognitive effect on the Iranian defenders. The Iranians will be thinking very seriously about what the American intent is. It could cause them to deploy their forces in a way that’s advantageous to you as the commander at sea.”
If the US Marines did land, one potential target would be Kharg Island, home to Iran’s main oil export terminal. Trump said on Friday that the United States had “obliterated” Iranian defences there.
Kharg lies some 300 miles from of the Strait of Hormuz, so the goal of such an operation would not be to physically unblock it, but to create enough economic pressure to force Iran to lift its blockade. But the island is not the only target.
The western mouth of the Strait is dominated by several Iranian islands, including Hormuz, which lends its name to the waterway.
Three of those islands present an intriguing diplomatic opportunity. The last Shah of Iran seized the trio – Abu Musa and the Greater and Lesser Tunbs – in 1971, despite the withdrawing British authorities promising them to what became the United Arab Emirates. They remain disputed territory, which means the White House could claim the operation was not an invasion of Iranian sovereign territory. The US could conceivably hand back control to Abu Dhabi in compensation for the chaos wrought by the war.
But the most ambitious – and potentially costly – option would be to land along the entire northern shore of the Strait of Hormuz, pushing Iranian forces back from the coast in order to protect the shipping lane. The US Navy and Marines are more than capable of creating the conditions for a simultaneous helicopter and sea-borne landing.
“But I think the challenge is then how you maintain your position in and around the Strait of Hormuz, if that is their intent,” says Burns. “The most challenging thing is to defend their positions against a concerted Iranian counterattack.”
There are some unhappy precedents for this kind of thing. In 1915, Britain and France tried an amphibious attack at Gallipoli to open the Dardanelles. The result was a year-long campaign involving half a million troops that failed to get more than a few miles of land.
The geography of Iran is even more mountainous and unforgiving than that at Anzac Cove. And the Ottomans did not have drones. If the Marines withdrew to avoid being drawn into such a disaster, the Iranians might resume pressure on the Strait as soon as they could.
The negotiating table
That, says RUSI’s Watling, is why the military solution must be supplemented by a political angle.
“If we think about what the Iranian government wants in terms of what it’s doing to the Strait of Hormuz, it wants to show the world that it can inflict enough economic pain that Iran cannot be attacked with impunity again. It wants to re-establish the deterrence that its ballistic missile arsenal was supposed to provide,” he says.
The American insistence on regime change means offering the Iranians that assurance as a quid pro quo for opening the Strait will be difficult. “The Iranians want the last word, to show the world that the US and Israel were compelled to withdraw and de-escalate. And Trump does not want to be seen to have been forced away from the issue,” says Watling.
There is one possible solution that would suit Iran and most of the rest of the world, but not the United States. It is conceivable that a diplomatic deal, brokered perhaps by China and supported by European countries anxious about an energy shock, could open the Strait for neutral tankers.
That would keep oil flowing to the rest of the world. But it would be a great blow to Trump’s prestige.