U.S. President Joe Biden has taken steps to avenge the deaths of William Rivers, Kennedy Sanders, and Breonna Moffett, the three U.S. service members killed by an Iranian-backed militia strike in Jordan on Jan. 28. The United States launched strikes on Iranian-linked targets in Syria and Iraq on Feb. 2.
Yet, whatever further steps Washington takes, shipping in the Strait of Hormuz will be in even more dire straits. Merchant vessels are deeply dependent on the waterway—where Iran, which controls one side of the strait, already regularly harasses shipping.
The strikes will, the United States hopes, send a clear message to Iran without escalating the indirect conflict into a direct one. Other acts of retaliation may follow. It “won’t just be a one-off,” National Security Council spokesperson John Kirby said on Jan. 31, adding that “the first thing you see won’t be the last thing.” Biden had already stressed that he doesn’t want escalation. “I don’t think we need a wider war in the Middle East. That’s not what I’m looking for,” he said on Jan. 30. But even if the fighting doesn’t spread, the strait just got a whole lot riskier.
The Strait of Hormuz is a crucial body of water. In 2022, 21 million barrels of oil traveled through the strait per day, which corresponds to 21 percent of the world’s global petroleum liquids consumption. It is also a chokepoint, a narrow body of water divided between Iran and Oman where traffic can easily be disrupted by storms, accidents, or willful acts by interested parties.
During the Iran-Iraq War in the 1980s, Iraq began attacking ships bound for Iran, and after a while, Iran retaliated. Soon, the Persian Gulf and the Strait of Hormuz were engulfed in what became known as the Tanker War. It was a wild war: The countries (especially Iraq) targeted merchant ships with rockets and land mines. Ships flagged in Cyprus, Greece, Iran, Japan, Kuwait, Liberia, Malta, Norway, Panama, Saudi Arabia, Singapore, Turkey, the United Kingdom, and other countries were hit.
But the ships kept sailing into the strait and the gulf anyway because the world needed oil. To get to the gulf and the oil, some ships “tried to slip through the Strait of Hormuz … at night, when the Iranian capability to attack ships is curtailed. Others, upon being challenged by Iranians at sea, attempted to ignore the challenge or misled the Iranians about their intended ports of call. One ship carried a false name on her hull,” Ronald O’Rourke wrote in the U.S. Naval Institute’s Proceedings magazine in 1988, as the war was ending. But the Iranians weren’t fooled. Determined captains then resorted to staying close to Western naval vessels, “preferably by joining a Western-led convoy traveling through the Gulf,” O’Rourke noted.
By the end of the Tanker War, more than 320 merchant mariners had been killed, injured, or were missing, while 340 merchant vessels had been damaged, some more than once. Some 30 million tons of shipping had been damaged, 11 ships had been sunk, and three dozen had been declared total losses. Though the Tanker War wasn’t Iran’s idea, the Iranians learned an obvious lesson from it: As long as the world needs oil, ships will need to go to the Persian Gulf, and that gives Iran a perfect opportunity to target ships of its choosing. That is, in fact, what it has increasingly been doing for the past five years. Last August, these attacks on merchant shipping prompted the United States to dispatch a task force of sailors, Marines, an amphibious assault ship, a dock landing ship, and other vessels to the strait.
They’re there to protect shipping because for as long as the world needs oil, ships will need to enter the Persian Gulf. And now that Washington will respond to the killings of the three U.S. service members, Iran can retaliate by harming ships in the Strait of Hormuz. “The loss of Persian Gulf oil would not affect the U.S. that much, but it would affect our allies,” said retired U.S. Navy Vice Adm. Andrew Lewis, who commanded the Second Fleet until 2021.
The shipping industry is already evaluating the risk of more attacks in the strait. “We’ve discussed this at length,” said Svein Ringbakken, the head of the maritime insurer DNK. “Regardless of whether this is the extent of the U.S. response or the U.S. also decides to retaliate against the IRGC [Islamic Revolutionary Guard Corps], the Iranians can attack merchant vessels. That’s what they’ve been doing for several years, and we’ve no reason to think they won’t use this opportunity.”
Indeed, Ringbakken noted, the Iranians could opt to do so surreptitiously: “They can hide behind plausible deniability and pretend that an intervention is linked to a previous accident, smuggling or the like, or perform attacks outside their own waters like in 2019.” That May, four tankers were attacked off the Emirati port of Fujairah near the Strait of Hormuz’s southern end; the United Nations subsequently found that the attacks had been perpetrated by an unidentified state actor. The following month, two tankers were attacked nearby.
As long as Iran doesn’t declare war on the United States or other countries linked to vessels traveling in and out of the Strait of Hormuz, there isn’t very much the U.S. or other countries’ navies can do to protect shipping there. “If it’s not a declared war, there are limits based on [the United Nations Convention on] the Law of the Sea,” Lewis said. Ringbakken added: “The navies can monitor and perhaps intervene in international waters, but apart from that, there isn’t a lot they can do.”
That gives Iran attractive opportunities. “Iran has proven capability, but it wouldn’t benefit from closing Hormuz, which is why it has been careful to keep its past actions limited,” said Neil Roberts, a secretary of the maritime insurance industry’s Joint War Committee, which assesses maritime risks. Indeed, Iran won’t need to try to shut the strait. It can just communicate that risks to merchant shipping there are about to increase. “The decision of whether oil will keep being transported from the Persian Gulf won’t be made at a national level but at a corporate level,” Lewis said. “The Strait of Hormuz will or will not shut down depending on how the industry reacts.”
Of course, if Iran were to escalate so massively that a new tanker war unfolded, the shipping industry and its insurers would have to make dramatic calculations. The Houthis’ attacks in the Red Sea have already increased risks for seafarers, but stepped-up attacks on shipping in the Strait of Hormuz would be far more dangerous.
In the 1980s, the industry was willing to tolerate not just sunk and totaled ships but also loss of life. Would that be the case today? It’s hardly a soft-hearted industry—just look at the more than 400,000 seafarers stranded on ships during the COVID-19 pandemic because countries wouldn’t let the ships dock—but 300-plus deaths might be a little much even by shipping’s standards.
“The question in case of a new tanker war would be whether modern sensibilities would be secondary to the need for supplies,” Roberts said. Whether global energy supplies matter more than seafarers’ lives may soon be a very concrete question. For now, Ringbakken said, “we have to live with the risk that the conflict will escalate.”