TEHRAN, July 12 — Iran’s threats to close the Strait of Hormuz have moved from rhetoric to a sustained action that, if it holds, would mark the first indefinite closure by the country. The waterway, a narrow chokepoint for global oil shipments, has seen previous disruptions, but never a full and open-ended shutdown by Tehran. The current closure represents an escalation from past incidents.
In December 2011, Iran’s then-Vice President Mohammad Reza Rahimi warned that Iran would block the strait if sanctions on its oil exports were imposed. The United States responded with naval deployments, and the threat subsided after negotiations.
That pattern — a warning, a show of force, a de-escalation — held for years.
A History of Tensions
In 2019, following the U.S. withdrawal from the Joint Comprehensive Plan of Action, or JCPOA, in May 2018 and the reimposition of sanctions, Iran shifted from threats to action. Iranian forces seized several oil tankers in the strait, including the British-flagged Stena Impero in July 2019. The U.S. formed the International Maritime Security Construct, or IMSC, in November 2019 to patrol the region.
Those incidents did not result in a full closure, but they highlighted the strait’s vulnerability. What is different now is the duration.
Previous disruptions were temporary. The current closure, if sustained, would be the first indefinite closure by Iran, marking an escalation from those earlier temporary disruptions. The U.S. administration has not yet announced a formal response to the closure.
The Strait of Hormuz connects the Persian Gulf to the Gulf of Oman and the open ocean. A sustained closure would affect oil shipments from major producers including Saudi Arabia, Iraq, the United Arab Emirates, Kuwait, and Iran itself.
The waterway has long been a flashpoint in U.S.-Iran tensions, and the current situation raises the stakes significantly. What to watch next: whether the U.S. administration will deploy additional naval assets to the region, and whether diplomatic channels can reopen before the closure becomes a prolonged crisis. The IMSC, established in 2019 to patrol the strait, remains in place, but its effectiveness in the face of an indefinite closure is untested.
