A narrow waterway connecting the Persian Gulf to the Gulf of Oman, the Strait of Hormuz has long functioned as a critical artery for global energy supplies. Roughly one-fifth of the world’s petroleum passes through it daily, a fact that has made the strait a recurring focus of geopolitical tension between Iran and Western powers.
The latest period of elevated risk follows a familiar pattern of Iranian threats and Western countermeasures, one that traces its origins to the Iran-Iraq War of the 1980s.
A Legacy of the Iran-Iraq War and the Tanker War
The historical record shows that during the Iran-Iraq War, which lasted from 1980 to 1988, both sides attacked oil tankers in what became known as the Tanker War, a campaign of maritime aggression that unfolded between 1984 and 1988. That conflict drew the United States into naval intervention under Operation Earnest Will, establishing a template for American military response to disruptions in the strait.
The Tanker War thus set a precedent for a cycle of Iranian provocation followed by Western sanctions or military responses. After the 1979 Iranian Revolution, the strait gained strategic weight as a new government in Tehran asserted control over the waterway, reversing decades of U.S.-backed influence under the shah. In the 1990s and 2000s, Iran repeatedly framed the strait as a line it would not allow others to cross, a stance that hardened further during nuclear negotiations in the 2010s.
In 2008, Iranian officials threatened to close the strait in response to potential sanctions, and in 2012 they again threatened closure over U.S. and European Union sanctions targeting Iran’s oil exports. The United States has consistently stated that it would use military force to keep the strait open.
Diplomatic Setbacks and Military Posturing
The 2015 Joint Comprehensive Plan of Action, known as the JCPOA, temporarily reduced tensions. But the U.S. withdrawal from the nuclear deal in 2018 and the subsequent escalation of sanctions heightened risks.
In 2019, after the U.S. withdrawal, Iran seized the British-flagged tanker Stena Impero in the strait. Sources familiar with the incident confirm the vessel was held for two months. The JCPOA is now effectively defunct, and sanctions remain in place, leaving the risk of miscalculation in the strait elevated.
In 2023, the Islamic Revolutionary Guard Corps Navy conducted exercises simulating a closure of the strait. That drill underscored the ongoing military dimension of the standoff and demonstrated that Tehran continues to rehearse closure scenarios.
Sources familiar with U.S. defense planning indicate that the Pentagon maintains contingency options for ensuring freedom of navigation through the strait. Operation Earnest Will remains a reference point for how the U.S. military might respond to renewed attacks on commercial shipping.
Legal Gaps and the Outlook Ahead
The United Nations Convention on the Law of the Sea guarantees transit passage through straits used for international navigation, but Iran is not a signatory to that convention. The absence of a binding legal framework for transit leaves the strait’s status unsettled, complicating legal arguments for transit rights.
Iran’s non-signatory status ensures that crises there can escalate quickly without a clear legal basis for resolution. The coming months will test whether diplomatic channels can prevent another confrontation. Most of the oil exported from Saudi Arabia, the United Arab Emirates, Qatar, and Kuwait must pass through the strait, making any disruption a potential shock to world supply.
For now, the U.S. position remains unchanged: the strait will stay open, by military force if necessary. The question is whether that resolve will be tested again.
With the historical pattern of escalation well established, and with both sides rehearsing their responses, the Strait of Hormuz remains a flashpoint where a single incident could draw the world’s attention once more.
