Foreign Affairs warns Iran's Hormuz closure has set 'cheap, fast and devastating' precedent for Malacca, Taiwan, Luzon and Lombok chokepoints

Writing in Foreign Affairs on May 22, the authors argue that Iran's late-February move to close the Strait of Hormuz — with drones, anti-ship missiles, mines, and Islamic Revolutionary Guard Corps warnings that "if anyone tries to pass, the heroes of the Revolutionary Guard and the regular navy will set those ships ablaze" — has done more than choke off Middle Eastern oil exports. By demonstrating that relatively inexpensive technologies and a willingness to disregard international law together suffice to weaponise a strategic strait, Hormuz has, in their view, lowered the threshold for similar action across Asia, the region whose waterways sit astride global trade, energy and semiconductor flows.

The piece details Tehran's tactics: a structured toll system requiring vessels to submit documentation and pay fees, with unconfirmed reports of at least one ship paying $2 million to transit, and a strait-closure capability built on coastal radar, shore-based missiles, drones, uncrewed surface vessels, fast attack boats and mines. The authors note that the mere threat of disruption is enough to raise insurance premiums, reroute shipping and unsettle commodity markets. Washington's mid-April response — President Trump's declaration that the US Navy would blockade "any and all Ships trying to enter, or leave, the Strait of Hormuz" — was, the authors argue, equally significant. The 21-nautical-mile Hormuz qualifies for the UNCLOS "transit passage" regime that applies to straits narrower than 24 nautical miles, granting ships and aircraft the right of unimpeded navigation. Trump's maximalist declaration was subsequently narrowed by US Central Command to an impartial blockade of vessels entering or leaving Iranian ports — a calibrated version the authors describe as legally defensible — but the maximalist version itself, they argue, signals a new tolerance of extensive economic costs and international-law violations.

The most acute Asian exposure is the Strait of Malacca. The 1.5-nautical-mile waterway carries up to 40 percent of global trade and 80 percent of China's energy imports; bypassing it requires routing through Indonesia's secondary waterways or around Australia at significant cost. The authors invoke the 2003 "Malacca dilemma" framing of then-President Hu Jintao and predict Beijing will accelerate plans to reduce dependence on the strait through overland pipelines via Myanmar, Russia and Central Asia, expanded Indian Ocean port access, and Arctic shipping routes. They note that Indonesia's finance minister recently floated the idea of charging tolls — perhaps "under the guise of an environmental levy" — before the foreign minister walked the statement back, while Singapore continues to capture the lion's share of the commercial value of passage through its port and transshipment services.

The Taiwan Strait, the authors argue, carries a different but equally severe risk profile. Twenty percent of global maritime trade passes through it; Taiwan remains the dominant producer of advanced semiconductors and lacks any geographic bypass, its major ports concentrated on the west coast facing the strait and its mountainous interior complicating east-west transport. Citing Bloomberg, the piece estimates 5.3 percent of global GDP could be erased by a strait blockade. The Hormuz precedent, in their reading, validates two asymmetric strategies that are already shaping force postures in the region: China's anti-access/area-denial (A2/AD) doctrine of layered missile, naval, air and surveillance systems, and Taiwan's "porcupine" approach of dispersed, mobile defensive platforms. Although the Taiwan Strait is roughly 70 nautical miles wide at its narrowest, requiring longer-range capabilities than Hormuz demands, the underlying principle — that straits are weaponisable strategic assets — applies.

Two further waterways figure prominently. The Luzon Strait, which links the South China Sea to the Pacific, has been the focus of US-Philippine exercises developing localised denial capabilities; its depth allows submarines to transit undetected. Beijing recently responded with live-fire exercises in the strait. Both the Taiwan and Luzon straits exceed the 24-nautical-mile UNCLOS threshold, meaning they contain continuous exclusive-economic-zone corridors in which high-seas freedoms apply — but the authors warn the strategic value of controlling them is likely to outweigh legal constraints in a crisis. The Lombok Strait, a deep-water trench between Bali and Lombok, has become a quieter theatre: in early April, Jakarta recovered an unmanned underwater vehicle of suspected Chinese origin in the waterway, and around the same time an Indian media outlet leaked an imminent US-Indonesia blanket overflight agreement, prompting Indonesia's foreign ministry to warn the defence ministry that the deal risked "the impression that Indonesia is involved in an alliance" and could entangle it in "a regional conflict situation." Beijing meanwhile warned the arrangement could violate the ASEAN Charter.

The authors close with a policy programme: bolster maritime domain awareness in Taiwan, Indonesia, Malaysia and Singapore; coordinate allied operations to maintain transit through contested straits in a crisis; upgrade secondary deep-water ports in the Philippines, Vietnam and along India's eastern seaboard; redouble efforts to decentralise advanced semiconductor production to allied countries such as Germany and Japan; and pre-commit to economic sanctions in response to unlawful disruption of major Asian waterways. They also urge Washington to finally accede to UNCLOS, a step the United States has so far declined despite generally accepting the convention's core provisions as customary international law — a credibility gap they argue now matters more than ever as Tehran's Hormuz playbook tempts imitators.