Beneath the shallow waters of the Gulf, shared between Qatar and Iran, lies the North Field — the largest single natural gas reservoir on earth. The Qatari portion is developed. The Iranian portion, called South Pars, is partially developed and severely constrained by sanctions and investment restrictions. What happens to the gas that Qatar extracts from its side of the reservoir determines energy supply conditions for electricity consumers in Japan, industrial gas buyers in South Korea, and power generators across Europe. All of it moves through Hormuz.

Iran’s nuclear program and the Strait of Hormuz are connected through a logic that diplomatic analysis frequently understates. The connection is not simply that a nuclear-armed Iran would be more willing to close the strait — though that proposition has its own merit. It is that the negotiations over the nuclear program, the sanctions imposed to pressure it, and the diplomatic settlements that have attempted to resolve it are all embedded in the same geopolitical relationship that determines whether the strait operates as a commercial corridor or a conflict zone. The nuclear file and the Hormuz file are the same file.

Between 1984 and 1988, Iranian and Iraqi forces attacked approximately 500 commercial vessels in the Persian Gulf. The Tanker Wars — that portion of the Iran-Iraq conflict that spilled into the maritime domain — were the most sustained campaign of attacks on commercial shipping since the Second World War. They established the template for how straits and sea lanes become instruments of war, how insurance markets respond to sustained maritime threats, and how major powers calculate the costs and limits of intervention in Gulf conflicts. The lessons were not adequately remembered in subsequent decades.

Approximately 20 million barrels of oil and petroleum products transit the Strait of Hormuz on an average day. The figure is so large and repeated so frequently in energy commentary that it has become almost abstract. Decomposing it into its constituent flows reveals a more specific picture of what is actually at stake — which countries, which companies, which commodity streams, and which supply chains run through twenty-one miles of contested water.

The United States Navy has been deploying unmanned surface vessels in the Persian Gulf in increasing numbers and on increasingly complex missions. Task Force 59, established in 2021 and headquartered at Naval Support Activity Bahrain, is dedicated to the integration of unmanned and autonomous systems into Gulf operations. The force has deployed unmanned surface vessels for maritime surveillance, tested autonomous coordination between multiple unmanned platforms, and begun experimenting with the integration of unmanned systems into the broader fleet architecture that conducts Gulf security operations. The experiment is significant because it is addressing the specific operational problem — too much water, too many threats, too few hulls — that has always characterized naval operations in the strait.

The Strait of Hormuz is a strait used for international navigation overlapping with the territorial waters of Iran and Oman. Under the United Nations Convention on the Law of the Sea, such straits are subject to the right of transit passage — a legal regime that grants all ships and aircraft the right to continuous and expeditious transit, and that limits the ability of coastal states to interfere with that transit. Iran has not ratified UNCLOS. It does not accept the transit passage framework. This legal disagreement is not merely academic. It is the normative foundation on which Iran’s claimed right to close or restrict the strait rests, and the normative foundation that every other party invokes to deny Iran that right.

The Strait of Hormuz is 90 miles long and between 21 and 55 miles wide. The navigable channel — the portion deep enough for laden very large crude carriers and the other substantial vessels that transit it — is much narrower. Two traffic separation lanes, each approximately two miles wide, handle the inbound and outbound commercial traffic, separated by a two-mile buffer zone. The effective transit corridor for a laden supertanker is therefore something on the order of two miles across, within a strait that appears much wider on maps but that shallow water, islands, and navigational hazards reduce to a constrained passage at the critical point.

Before a single missile is fired, before a mine is laid, before a naval vessel changes course, the insurance market registers the threat. War risk premiums on tankers transiting the Persian Gulf are among the most sensitive geopolitical indicators available. They move faster than official statements, faster than military repositioning, and faster than most news coverage. The underwriters at Lloyd’s of London are not strategists, but their pricing reflects a continuous aggregation of threat intelligence that rivals most government assessments.