Why a Hormuz blockade is more bluff than brinkmanship

As tensions soared in mid-June after US and Israeli military strikes hit Iranian nuclear sites, Tehran’s most alarming response wasn’t a direct military counterattack—it was the implicit threat to close the Strait of Hormuz, the world’s most important energy chokepoint. That narrow stretch of water funnels a third of global oil exports. If Tehran were to block it, the consequences could be seismic. But would Iran really go that far? A close analysis of international maritime law, economic imperatives, and Iran’s historical behavior reveals that while the threat is real enough to rattle markets, a full-scale closure remains improbable.

Iran’s geographic proximity to the Strait of Hormuz gives it undeniable leverage. At its narrowest, the passage is just 33 kilometers wide, flanked by Iran to the north and Oman to the south. Roughly 15 to 17 million barrels of oil pass through it daily—most destined for Asia. It’s no wonder the strait has become a geopolitical pressure point.

But physical proximity does not equal legal control. Under the United Nations Convention on the Law of the Sea (UNCLOS)—to which Iran is a signatory—the Strait of Hormuz qualifies as an international strait. That means all ships and aircraft enjoy “transit passage”, a right that “shall not be impeded” even during times of heightened conflict. In effect, Iran is legally bound to allow uninterrupted commercial and military navigation through the strait.

If Iran were to attempt a closure, it would be in direct violation of international law, opening the door to diplomatic isolation or even military response under the guise of defending global commons. And given that Iran has long relied on UNCLOS to defend its maritime rights elsewhere, such a move would be both hypocritical and self-defeating. Furthermore, the strait is regularly patrolled by the US Navy’s Fifth Fleet, based in Bahrain, alongside allied naval forces from the UK and France. Any Iranian effort to impose a naval blockade would be met with overwhelming resistance. As one military analyst put it, “Iran can harass traffic in Hormuz—but it can’t own it.”

While Iran’s threat to close the strait is often framed as a show of strength, it may actually betray weakness. In truth, Iran’s economy is deeply dependent on oil exports—and those exports overwhelmingly rely on the Strait of Hormuz.

Although the Goreh-Jask pipeline allows Iran to bypass Hormuz for a small share of its oil shipments, over 80% of its crude still exits via the strait. Blocking it would mean slashing its own revenues, especially damaging at a time of crippling inflation, high youth unemployment, and limited access to foreign reserves due to sanctions. It’s not just oil sales. Iran also relies on maritime trade for essential goods, including food, medicine, and manufactured imports. A prolonged closure would worsen supply chain constraints, damage domestic industry, and likely trigger domestic unrest.

Moreover, key buyers like China and India—already cautious about secondary sanctions—would hesitate to keep importing oil from a nation that is actively destabilizing global markets. Iran’s Gulf neighbors would seize the opportunity to fill the void, further diminishing Iran’s energy influence. In effect, Tehran would be sabotaging the very income stream that funds its defense and nuclear ambitions.

In short: threatening Hormuz is easy. Closing it is economic suicide.

So why make the threat at all? Because it serves as a powerful deterrent signal in the language of geopolitics. Tehran’s reference to Hormuz isn’t necessarily a promise—it’s a warning. By reminding the world of the damage it could inflict, Iran aims to raise the costs of confrontation and pressure adversaries back to the negotiating table. This is a classic playbook in asymmetric warfare. Iran lacks the conventional firepower of the US or Israel, but it excels in gray-zone tactics—sabotage, proxy attacks, and symbolic threats that create ambiguity. Hormuz, with its global economic importance, is a perfect tool for this kind of signaling.

This isn’t the first time Iran has rattled the Hormuz saber. During past crises—such as the 2011 sanctions ramp-up, the 2019 tanker attacks, or the fallout from Qassem Soleimani’s assassination in 2020—Iran made similar threats. None materialized into a full closure. The pattern is consistent: Tehran makes the threat, watches global markets react, gauges diplomatic openings, and steps back before pushing too far. It's coercive diplomacy with plausible deniability.

But the danger is not in the strategy—it’s in the possibility of miscalculation. An accidental naval collision, a misfired missile, or a rogue militia attack on a tanker could escalate far beyond Tehran’s intended signal. That’s what makes the Hormuz standoff so volatile. The risk isn’t a planned closure—it’s an unplanned crisis.

Markets have already responded. After the June strikes and Iran’s initial threat, Brent crude spiked nearly 14%, touching US$79 per barrel before falling back to US$68 once a ceasefire took hold. This swing reflects investor anxiety about geopolitical risk premiums—anxiety that could persist even if the strait stays open.

Energy-importing nations in Asia, particularly Japan, South Korea, and Southeast Asia, are especially exposed. More than 70% of the oil passing through Hormuz goes to Asia, and few countries have the strategic reserves to absorb a prolonged shock. Governments across the region are now reassessing their contingency plans and energy sourcing strategies.

Meanwhile, shipping insurers have raised premiums for transit through the Persian Gulf, and some carriers are beginning to reroute—potentially increasing costs and delays. The psychological toll of Hormuz insecurity is already reshaping global supply chain planning.

There are also military and diplomatic implications. Gulf states are being pulled deeper into the orbit of U.S.-led naval coordination. China, Iran’s key partner, faces a delicate balancing act: it needs Persian Gulf energy but also wants to avoid being drawn into an American-led regional order. That tension may test Beijing’s “pro-Iran but pro-stability” doctrine.

Iran’s threat to close the Strait of Hormuz is not empty—but it is unlikely to be realized in full. Legally, Iran is constrained. Economically, it is cornered. And strategically, it has far more to lose than gain from turning a global trade artery into a warzone. Still, the threat is meaningful. It reminds global powers that the Middle East remains a powder keg. It puts pressure on oil-importing economies to diversify energy routes. And it signals that Iran views economic pain as a bargaining chip in nuclear diplomacy.

But Tehran’s leaders are not irrational. They are strategic players operating in a constrained environment. Unless attacked again or faced with existential peril, Iran is unlikely to initiate a closure that would alienate its allies, destroy its revenue, and justify international retaliation. For now, the Strait of Hormuz remains open—but the channel for miscalculation has never been narrower. The world must take the threat seriously, not because it’s inevitable, but because it’s one mistake away.