Three small islands sit near the entrance of the Strait of Hormuz. Abu Musa belongs to the emirate of Sharjah. Greater Tunb and Lesser Tunb belonged to Ras al-Khaimah. In November 1971, two days before the British protectorate over the Trucial States expired and three days before the United Arab Emirates came into formal existence as an independent nation, Iranian forces occupied all three. Greater Tunb was taken by force, killing several Ras al-Khaimah police officers who attempted to resist. Abu Musa was occupied under a memorandum of understanding with Sharjah that Iran has since interpreted in ways that effectively amount to full occupation. The UAE has never accepted any of this. The dispute is over fifty years old and shows no sign of resolution.

The Supreme Leader of the Islamic Republic of Iran is eighty-five years old. His health has been the subject of sustained speculation for years, with periodic reports of serious illness that the Iranian government neither confirms nor adequately denies. The succession question is not speculative. It is operational. The individuals and factions positioning for post-Khamenei influence are doing so now, and their relative strength when the transition occurs will determine whether the Islamic Republic emerges from succession in a more confrontational or more accommodating posture toward the outside world, and toward Hormuz specifically.

Saudi Aramco processes more oil through fewer facilities than any other company on earth. The Abqaiq oil processing facility in the Eastern Province handles a majority of Saudi crude production, stabilizing and processing it before it moves to export terminals. Ras Tanura is the largest oil loading port in the world. These facilities — concentrated, critical, and heavily defended — represent the upstream end of a supply chain whose downstream end runs through Hormuz. An attack on Abqaiq or a closure of the strait produces the same downstream effect: Saudi crude stops reaching its buyers. The two risks are linked by geography even when they originate from different threats.

Bahrain is the smallest country in the Gulf and hosts the most consequential piece of American military infrastructure in the Middle East. Naval Support Activity Bahrain, home to the US Fifth Fleet and Combined Maritime Forces, occupies ground in the island kingdom that no other location in the Gulf could replicate — deep-water access, proximity to the strait, political stability sufficient to sustain a permanent large-scale military presence, and a host government whose security dependence on the American relationship is clear-eyed and durable. The base is there because the geography and the politics aligned. Both continue to hold, under conditions that are more complicated than they appear.

Iran operates submarines in the Strait of Hormuz and the broader Gulf of Oman. The fleet is not large, and the vessels are not modern by the standards of major naval powers. What they represent is a persistent underwater presence in one of the world’s most difficult antisubmarine warfare environments — a shallow, thermally layered, acoustically cluttered body of water where detection is genuinely hard and where even a small submarine with limited capability poses a disproportionate threat to shipping and to surface naval forces.

China imports more oil than any other nation on earth. A majority of that oil originates in the Persian Gulf. The overwhelming majority of that Gulf oil moves through the Strait of Hormuz. This dependency is the most significant structural vulnerability in the Chinese economy, and Beijing has spent the better part of two decades trying to reduce it without succeeding in any meaningful way.

The arithmetic is unforgiving. China’s oil import dependence has risen, not fallen, as its economy has grown. Domestic production has plateaued and is declining at the margin. The non-Gulf sources that Beijing has cultivated — Russia, Angola, Brazil — are real but insufficient to replace Gulf supply. When analysts calculate what a thirty-day closure of Hormuz would do to Chinese industrial output, the numbers become politically significant very quickly. Beijing’s strategic planners know this. They treat it as the central energy security problem that has no clean solution.

A tanker that does not appear on tracking screens is not invisible. It is simply operating in the gap between the legal obligation to broadcast its position and the practical inability of enforcement authorities to impose consequences for failing to do so. Iran has exploited that gap systematically and at scale, building a sanctions evasion infrastructure that has kept its oil revenues flowing through periods when official exports were near zero, and learning, in the process, the operational techniques of maritime concealment that have military implications beyond their immediate commercial function.

The 2019 attack on the Abqaiq oil processing facility used cruise missiles and drones. The subsequent attacks on tankers in the Gulf of Oman used limpet mines and, in some cases, explosive-laden fast boats. By the time Houthi forces began their Red Sea campaign in late 2023, the weapons mix had evolved to include one-way attack drones and ballistic missiles fired against commercial vessels. The technological trajectory is consistent: unmanned systems are becoming a larger share of the threat to shipping in and around the Persian Gulf, and their characteristics — low cost, deniability, saturation potential, and steadily improving accuracy — make them a structural shift rather than a tactical adaptation.

Before February 2022, European energy security analysis treated the Persian Gulf as a significant but secondary concern. The primary vulnerabilities ran through Ukrainian pipeline corridors and Russian supply decisions. Hormuz was a risk to Asian energy markets, to oil prices globally, and to a residual flow of LNG from Qatar to a handful of European regasification terminals that had been built for flexibility rather than baseload supply. The invasion of Ukraine changed this with a speed that European energy planners had not fully modeled. By the end of 2022, Europe was competing in global LNG markets for volumes that included substantial Qatari supply, and its exposure to events in the Persian Gulf had become structurally different from anything its policy frameworks had anticipated.

The Strait of Hormuz has a sister chokepoint at the other end of the Arabian Peninsula. Bab-el-Mandeb, the narrow passage between Yemen and Djibouti that connects the Red Sea to the Gulf of Aden, carries the maritime traffic of the Suez Canal route — container ships, bulk carriers, tankers moving between Europe and Asia, and LNG vessels serving European regasification terminals. When Houthi forces in Yemen began attacking commercial shipping in the Red Sea in late 2023, they demonstrated that Iran’s sphere of proxy influence could threaten two of the world’s most critical maritime corridors simultaneously.