Closing the World’s Jugular

Trump’s Hormuz blockade seeks to weaponize a chokepoint that history shows is far easier to disrupt than to control.

Across centuries, for rulers and states alike, to command a narrow strait has been to wield power far out of proportion to its geography. From the Hellespont of antiquity to the Danish Sound, chokepoints have tempted them with the promise of effortless leverage. The Strait of Hormuz is the latest test of that enduring illusion.

If the latest stream of conflicting signals from the U.S.-Iran standoff is any guide, the strait is both open and not. Iran’s Speaker warns it will “not remain open” if American pressure continues. U.S. President Donald Trump insists it is “open and ready for business,” even as he vows to maintain a naval blockade until a broader deal is struck. Earlier, Iran’s Foreign Minister had declared Hormuz “completely open” under the ceasefire. However, tracking data shows that tanker traffic has been reduced to a trickle.

Trump’s blockade of Iranian ports - which officially came into force following the collapse of high-stakes peace negotiations in Islamabad between the U.S. and Iran - is perhaps the most consequential act of economic warfare since the Cold War.

It rests on the familiar premise that economic strangulation can achieve what diplomacy and bombardment have not. History, however, suggests that the United States President is not the first to attempt it and that such gambits rarely unfold as intended.

Since the outbreak of hostilities, Iran has charged as much as $2 mn per transit. Between March 30 and April 5, 51 of the 72 vessels that passed through Hormuz appear to have complied.

On paper, Iran is deeply vulnerable to Trump’s blockade. According to Miad Maleki, a senior fellow at the Foundation for Defense of Democracies (FDD) who previously worked as a senior U.S. sanctions strategist, the U.S. naval blockade of Hormuz would cost Iran approximately $276 mn a day in lost exports and disrupt $159 mn day in imports, resulting in a combined economic damage of $435 mn a day, or $13 bn a month.

Before the blockade, Iran exported roughly 1.5 million barrels per day, earning about $139 million daily at wartime prices, said Maleki. Kharg Island, the terminal that handles around 92 percent of crude exports, has no viable substitute. Given limited storage, production may have to be curtailed within weeks of effective interdiction.

Thus, a sustained blockade would act as a tourniquet on the regime’s economic lifeline by this logic. Secondly, experts opine that Iran’s supposed escape routes are largely illusory. Jask, the bypass terminal on the Gulf of Oman, was designed for a million barrels per day but operates at a fraction of that. Chabahar handles general cargo but is not configured for bulk crude at scale.

The more immediate vulnerabilities lie on the import side. One-fifth of Iran’s wheat has historically arrived via Gulf ports. Most maize is sourced from Brazil and Ukraine. Soyabeans, essential for animal feed and vegetable oil, are almost entirely imported by sea. (Food prices were already more than 100 percent higher in March than a year earlier)

The instinct to weaponize Hormuz is not new; nor is the difficulty of translating economic pressure into political compliance. In 1838, Britain deployed its Indian Ocean squadron to coerce Persia during a dispute over Herat. It did so again in 1856–57 during the Anglo-Persian War, seizing Bushire and exerting temporary control over Gulf traffic. In both cases, coercion produced concessions but not a lasting settlement.

A more sophisticated attempt came in 1951, when Britain responded to Iranian Prime Minister Mohammad Mosaddegh’s nationalisation of the Anglo-Iranian Oil Company by imposing what amounted to an oil blockade. Through naval pressure, insurance restrictions and diplomatic coercion, London choked off Iranian exports. The economic damage was severe but Mosaddegh did not yield. He fell only after the coup orchestrated by the CIA and MI6 in 1953.

The Tanker War of 1984–88 reinforced the lesson. As the Iran–Iraq conflict spilled into the Gulf, both sides began attacking oil tankers and commercial shipping in an effort to strangle each other’s revenues. Iraq, backed by Western and Gulf intelligence, targeted Iranian exports; Iran retaliated by striking vessels linked to Iraq’s Arab supporters, particularly Kuwait and Saudi Arabia. The conflict quickly snowballed onto a global stage. Kuwait sought protection by reflagging its tankers under the American flag, prompting the United States to launch Operation Earnest Will in 1987 to escort convoys through Hormuz.

The risks were immediate and tangible. In 1987, an Iraqi aircraft mistakenly struck the USS Stark, killing 37 American sailors. In 1988, the USS Samuel B. Roberts was severely damaged by an Iranian mine, bringing the United States into direct confrontation with Iran. Operation Praying Mantis followed in April that year: a single day of fighting in which American forces sank or crippled much of Iran’s operational navy and destroyed offshore platforms used for military purposes. It was the largest U.S. naval engagement since the Second World War and a decisive demonstration of conventional superiority.

But even this overwhelming display of American conventional superiority did not settle the strategic question. For Iran, direct confrontation against a technologically superior adversary had exposed the limits of its fleet.

This prompted Tehran to completely change future terms of engagement as it replaced its frigates with mines while coastal missiles extended reach without inviting direct engagement.

Hormuz today is a dense intersection of global interests as Asian importers, Gulf producers, Western navies and regional rivals all converge within its narrow confines, each with different thresholds for risk.

It is a system under strain. And recent days have made clear that amid conflicting and unyielding signals from both Iran and the U.S., it is uncertainty and hesitancy that is reigning supreme. During the Suez crisis of 1956 and again after the Six Day War of 1967, the Canal became unusable, causing the redirection of global trade for years. Something similar is unfolding in Hormuz today, where risk or the threat of it is determining movement along the strait.

To squeeze the world’s jugular is therefore not merely to exert pressure on an adversary but to tamper with a system that has never been entirely controllable. For history shows that while chokepoints are often weaponized, they rarely behave as expected once they are.

Five Centuries of Toll-Takers

From Albuquerque’s cannon to the English East India Company’s ledgers, every empire that reached the Gulf swiftly understood that Hormuz was a waterway to be weaponized.

By the early 16th century, the kingdom of Hormuz (whose rulers were nominally vassals of the Persian Safavid shah) functioned as a key entrepôt, linking Persian, Arab and Indian Ocean commerce. It derived much of its wealth from taxing passing trade.

The Portuguese were the first Europeans to grasp the strait as a systemic instrument of power. Afonso de Albuquerque arrived at Hormuz in 1507 with a small but disciplined fleet. His methods were theatrical and brutal, and involved burning vessels in the harbour, mutilating prisoners and dispatching their severed limbs as a prelude to negotiation. This extreme violence as policy worked as the ruling Hormuzian monarch, the young Seyf al-Din, was effectively reduced to a client under Portuguese supervision while real authority came to be exercised through a regency aligned with Albuquerque’s interests. Hormuz became a cornerstone of the Estado da Índia.

From this position, the Portuguese imposed the cartaz system, a maritime licensing regime that extended far beyond the Gulf. Any ship sailing the Indian Ocean was required to carry a Portuguese pass and those that did not were liable to seizure, with their cargo confiscated. The diktat was that trade – which included spices from India and Southeast Asia, Persian silk, Arabian horses - could flow, but only under Portuguese supervision and taxation. Hormuz, strategically placed at the mouth of the Gulf, became a customs gate backed by Portuguese cannon. Revenues extracted here helped sustain Portugal’s far-flung empire, linking East Africa, India and Southeast Asia into a single, if fragile, commercial system.

The Ottomans, whose imperial reach extended from the Mediterranean to Mesopotamia, were quick to recognise the threat. Their own ambitions in the Indian Ocean were driven as much by commerce as by rivalry with Iberian powers. Two serious attempts were made to challenge Portuguese dominance. In 1552, a fleet under the Ottoman admiral Piri Reis entered the Gulf and threatened Hormuz, demonstrating that Ottoman naval power could project into these waters. Yet the effort faltered, and a subsequent expedition under Seydi Ali Reis ended in disaster, with ships wrecked and crews forced into arduous overland journeys back to Ottoman territory.

The Ottomans retained control of Basra and influenced the northern Gulf, but they never secured Hormuz itself. By allowing the Portuguese to maintain their hold on the strait, the Ottomans effectively conceded a key node in the Indian Ocean trading system. The Estado da Índia’s dominance persisted for over a century, illustrating how control of a single chokepoint could shape the commercial architecture of an entire ocean.

It was Shah Abbas I of Persia who eventually broke this monopoly, and he did so by adapting rather than confronting European naval power. For him, the Portuguese presence at Hormuz was not merely an economic inconvenience but a political affront. Yet Persia lacked a navy capable of dislodging them. The solution was an alliance of convenience.

In 1622, Safavid forces, supported by ships of the English East India Company, launched a coordinated assault on Hormuz. The English provided the naval firepower; the Persians supplied the manpower on land. The Portuguese, isolated and overstretched, were expelled in a matter of weeks. The Portuguese system had tied trade physically and fiscally to the island of Hormuz; its fall severed that link. Rather than attempting to revive the island as a commercial hub, Shah Abbas made a deliberate strategic choice to shift the centre of gravity to the mainland to Bandar Abbas - a modest port that was expanded and repurposed into the new entrepôt of the Gulf.

Under Portuguese rule, duties collected at Hormuz had flowed outward, sustaining an empire headquartered in Lisbon. Under Safavid control, they were internalised, feeding into the fiscal machinery of the Persian state. The wealth generated by the Gulf trade helped finance Safavid state-building, including the architectural splendours of Isfahan.

For the English East India Company, access to Persian silk and Gulf trade routes strengthened its position in the Indian Ocean. By the 19th century, the British Empire, preoccupied with securing sea routes to India, adopted a less overt but no less effective approach. Rather than imposing a universal licensing system like the cartaz, Britain established a framework of treaties with local rulers along the Trucial Coast. The General Treaty of 1820, followed by a series of Exclusive Agreements, effectively placed the southern Gulf under British protection and influence.

The objective was to exclude rival powers - particularly France and Russia - from establishing a foothold.

The discovery of oil in Persia in 1908 transformed the stakes. Hormuz, once a conduit for diverse goods became an artery for a single, strategic commodity. The rise of the Anglo-Persian Oil Company and the subsequent integration of Gulf energy into global markets repriced the importance of Hormuz in industrial terms.

Across the centuries, the temptation to turn the Hormuz leverage into absolute control has been constant. The difficulty of doing so has been equally enduring.

Blockade and Its Discontents

As opposed to conventional warfare, economic warfare has long promised decisive outcomes at a distance. While it offers the prospect of coercion without costly boots-on-the-ground occupation and prolonged bloodshed, history shows that the results have been a decided mixed bag.

The modern logic of economic warfare was articulated with particular clarity during the Napoleonic Wars (1803-1815). In 1806, after he smashed the Prussians at Jena-Auerstedt, Napoleon Bonaparte issued the Berlin Decree which inaugurated the Continental System - an attempt to exclude British goods from all European ports under French control or influence. A year later, the Milan Decree extended the system further, declaring that any neutral ship complying with British regulations, or even touching at British ports, would be liable to seizure. The aim was the complete economic isolation of Britain by severing it from continental markets and forcing it to negotiate.

The strategy rested on a plausible diagnosis that Britain’s strength lay not only in its navy but in its commercial reach, in its ability to finance war through trade, credit and taxation. By denying it access to European markets, Napoleon believed that Britain’s war-making capacity would wither. But the implementation of the Continental System revealed the limits of economic coercion. Given Europe’s coastline is vast and porous, smuggling through the Iberian Peninsula and the Baltic became endemic while neutral carriers found ways to circumvent French restrictions, often with tacit local support.

More fundamentally, the system imposed heavy costs on the continent itself as European consumers were cut off from British manufactured goods and colonial imports such as sugar and coffee. Industries dependent on imported inputs struggled. Enforcement required an intrusive apparatus of surveillance and control, breeding resentment among allies and subject states alike. Russia – then a Napoleonic ally - whose economy depended heavily on exports to Britain, grew increasingly restive. Its decision to abandon the Continental System in 1810 was one of the precipitating causes of Napoleon’s disastrous invasion two years later.

Britain, meanwhile, proved more resilient than anticipated. It redirected trade towards Latin America, the Mediterranean and its expanding imperial network. The Royal Navy enforced its own counter-measures restricting neutral trade with France and its allies. London’s financial system, underpinned by the Bank of England and a sophisticated market for government debt, continued to fund the war effort. Far from collapsing, Britain adapted, even as parts of continental Europe bore the brunt of disruption.

The Continental System is a cautionary example of economic warfare’s double-edged nature.

But a century later, the First World War offered a more systematic and more devastating application of blockade strategy when Britain’s naval cordon on Germany restricted imports of food, fertilisers and key industrial inputs. The effects were cumulative and severe. By 1916–17, the so-called ‘Turnip Winter’ saw urban populations subsist on animal fodder as staple foods disappeared. Malnutrition spread, particularly among children; infant mortality rose sharply, and civilian health deteriorated across the Reich. While estimates vary, historians generally attribute between 400,000 and 750,000 German civilian deaths to starvation and disease linked to the blockade, with children and the elderly disproportionately affected.

Germany responded with its own form of economic warfare. In 1916, the High Command had embraced unrestricted submarine warfare, calculating that sinking Allied shipping faster than it could be replaced would force Britain to the negotiating table within months. The arithmetic appeared compelling but the conclusion was mistaken. Once again, Britain adapted by introducing convoy systems, expanding shipbuilding and drawing on imperial supply networks. While the German campaign failed to deliver a knockout blow, it instead helped draw the United States into the war, decisively altering the strategic balance.

If the British blockade contributed to Germany’s eventual exhaustion, the suffering it inflicted became a powerful element in post-war German memory, feeding narratives of victimhood and grievance. The continuation of blockade conditions even after the armistice, until the signing of the Treaty of Versailles in 1919, deepened that resentment. Economic warfare had helped weaken Germany. It had also helped sow the bitterness that would shape its future.

Later cases show that while economic pressure can indeed inflict real hardship, they rarely translate into decisive political submission. Sanctions on Iraq in the 1990s devastated living standards without dislodging Saddam Hussein. Measures imposed on Iran itself in the 2010s, particularly after 2018, sharply reduced oil exports and triggered currency collapse. Tehran adapted by rerouting trade, expanding informal networks and absorbing economic strain domestically.

What emerges from this is while economic warfare can impose substantial costs and shape strategic choices, it rarely delivers immediacy.

Trump’s blockade of Hormuz now sits within this longer tradition. Its premise that cutting off Iran’s flows of trade and revenue will compel rapid political change is as old as Napoleon’s decrees. The search for a shortcut to victory, conducted through markets rather than battlefields, has a long and inconclusive history.