TEHRAN, Aug. 6 — A committee inside Iran’s parliament has begun reviewing draft legislation that would bar American- and Israeli-owned or operated vessels from transiting the Strait of Hormuz, the maritime chokepoint that carries an estimated 20-30% of the world’s seaborne-traded oil. The bill, introduced in the Islamic Consultative Assembly, arrives at a moment of sharpened tension between Tehran and the West. It is the latest in a long line of Iranian moves to turn geography into leverage.
The numbers explain why the world is watching. At its narrowest point, the strait is approximately 21 nautical miles wide, a thin ribbon of water connecting the Persian Gulf to the Gulf of Oman.
According to the U.S. Energy Information Administration, an estimated 20-30% of the world’s seaborne-traded oil passes through it daily — crude that feeds refineries, power plants and the daily commutes of millions. Iran holds the strait’s northern shore. Oman and the United Arab Emirates line the south.
Tehran has long asserted control over the waterway, pointing to its geographical position as justification. International law tells a different story: the United Nations Convention on the Law of the Sea (UNCLOS) designates Hormuz as an international strait, where the right of transit passage cannot be suspended.
For the crews aboard the tankers that thread these waters, the legal fine print matters less than the reality that a single decision in Tehran can close the route they sail.
Tensions, old and renewed
The draft bill reflects a standoff that has deteriorated steadily since May 2018, when the United States withdrew from the Joint Comprehensive Plan of Action and reimposed sanctions on Iran. In the years since, the strait has repeatedly surfaced as a flashpoint. The threat, in other words, is not new.
In 2018 and again in 2019, Iran’s Revolutionary Guard threatened to close the strait in response to what it framed as provocations, as U.S. sanctions and military deployments piled pressure on the Islamic Republic. This bill would formalize a version of that threat — shifting it from rhetoric in a military command to the letter of Iranian law.
A long road to law
Passage is far from guaranteed. The draft would still need approval from the Guardian Council, the 12-member body that vets all legislation for compliance with Islamic law and the Iranian constitution. That review process leaves room for the measure to stall, be amended or die quietly — but the simple fact of its consideration signals Tehran’s appetite for keeping the strait at the center of its confrontation with Washington.
The waterway has been here before. During the 1980s Tanker War, fought amid the Iran-Iraq War, both sides targeted oil tankers and merchant vessels, turning a vital commercial lane into a battleground and pulling international navies into the Gulf to protect shipping.
The memories of that conflict still shape how the region’s capitals read any new threat to Hormuz.
What to watch
For now, the question is whether the committee advances the bill to the full chamber — and how the international community reacts if it does. The strait’s legal status under UNCLOS, and the dependence of global energy markets on its waters, mean that even a draft proposal carries weight in shipping offices from Singapore to Rotterdam. Iran has historically wielded the threat of closure as a bargaining chip rather than a final act.
The calculation for Washington and its allies is whether this is another round of pressure, or the opening of a more dangerous phase.
