Global trade faces new era of maritime vulnerability as powers weaponize chokepoints

Two thousand four hundred years ago, a Spartan commander named Lysander understood something that modern policymakers are learning the hard way: control a narrow passage of water, and you control an empire. He blockaded the Dardanelles, starved Athens of grain, and watched a civilization surrender without a shot fired. Today, the world's economy depends on a handful of similar passages—narrow straits and canals where billions of dollars in cargo funnel through each year, vulnerable to anyone with the will and means to choke them off.

The Strait of Hormuz, thirty miles wide at its narrowest point, is the most critical of these passages. It is the only sea route connecting the oil-rich Persian Gulf to the rest of the world. In February, after the United States and Israel attacked Iran, Tehran announced it had seized control of the strait. Washington responded with its own blockade of Iranian ports. The result has been swift and brutal: vessel traffic through Hormuz has collapsed to hundreds of ships per month, down from the usual thousands. Oil prices have surged more than forty dollars per barrel. Gasoline and diesel are scarce. Jet fuel and fertilizer are already running short. Food prices are climbing. Experts are openly discussing stagflation—the toxic combination of stagnation and inflation that crippled economies in the 1970s.

Before this crisis, disruptions at maritime chokepoints were already costing the global economy roughly fourteen billion dollars annually, according to researchers at Oxford University. They studied the world's strategic canals, passages, and straits—places where large flows of trade converge into tight spaces. Some are literal channels of water; others, like the Cape of Good Hope, are routes where the sheer volume of vessels creates vulnerability. The Suez Canal, the Panama Canal, the Turkish straits, the Malacca Strait—each one is a potential pressure point. And now, major powers are treating them as such. Vincent Clerc, chief executive of Maersk, the world's second-largest container shipping company, put it plainly: "Some of these trade routes have been weaponised to an extent that we have not seen before."

The competition for control is intensifying. President Trump has threatened to seize the Panama Canal, accusing China of trying to dominate it. In response, analysts expect Beijing may revive a long-dormant plan to build a rival canal through Nicaragua. A Russian-Chinese naval exercise off South Africa's coast in January sent a signal to the world: the great powers are positioning themselves to exert pressure on the routes that matter most. The Indian Ocean, through which two-thirds of global oil and one-third of all cargo passes, has become a theater of competition between the United States, China, and Russia. Researchers at Chatham House note that the countries participating in or observing that exercise—Egypt, Ethiopia, Indonesia, the United Arab Emirates, and South Africa—all sit near or along the Indian Ocean's major chokepoints. For China, the stakes are existential. Beijing's Belt and Road initiative has always been, in part, about building alternatives in case the United States closes off the traditional routes. Now, with the Hormuz crisis unfolding, that logic seems prescient.

When a chokepoint closes, the consequences depend on whether alternatives exist. Shipping companies have learned to reroute around the Suez Canal, taking their vessels eight thousand miles around the Cape of Good Hope to avoid Houthi militants who began attacking ships in the Red Sea in 2023. The detour is expensive and time-consuming, but it is possible. The Strait of Hormuz offers no such escape. Eighty percent of the trade flowing through it has nowhere else to go. A study into the risks of the world's twenty-four narrow straits found that when Hormuz is blocked, there is simply no alternative. The consequences ripple outward in ways that are difficult to predict. West African nations, with no direct Middle East connections, are being hit hard as fertilizer shortages threaten harvests and push food prices higher. A logistics executive in Denmark noted the brutal arithmetic: "When everything is flowing, you don't consider your job vital. But if you can't get cargo in, the people there can't eat." Some companies are attempting radical workarounds—moving goods overland through Saudi Arabia and Turkey, using trucks and pipelines to replace the capacity of massive container ships. It is a fraction of what the sea routes normally carry, and it is not enough.

The longer the disruption persists, the more the world's supply chains contort. Experts speak of a "rule of thumb": for every week the Strait of Hormuz remains closed, expect a month of disruption downstream. As the crisis stretches into months, policymakers are bracing for recession. Industrial shutdowns loom. Fuel rationing may become necessary. The fear is no longer abstract—it is immediate and spreading.

Yet the Hormuz crisis may be only the beginning. Analysts warn that other actors—rebel groups, smaller nations, ambitious powers—may learn from Iran's success and attempt similar leverage over their own chokepoints. The cost of posing the threat is low; the cost of guaranteeing safety is high. The worst-case scenario, many experts agree, would be a conflict between China and Taiwan. The Taiwan Strait carries one-fifth of all global maritime trade. A closure would require only a short diversion to navigate around—but the broader economic and geopolitical shock would be catastrophic. In the meantime, the world is learning that the routes that move its goods are not neutral passages. They are prizes. And in an era of rising geopolitical tension, they are increasingly being treated as weapons.