Navigating Conflict: Legal Dimensions of Iran’s Control over the Strait of Hormuz

by MD MUNEEB HUSSAIN

Can Iran lawfully restrict one of the world’s most important shipping routes during armed conflict? The answer is less clear than it should be. While Iran’s actions in the Strait of Hormuz fall short of a formal blockade, they still expose commercial vessels to growing legal and military risks. The real problem lies deeper: a fragmented legal framework where States disagree on the rules themselves. In this grey zone, law does not prevent conflict, it reshapes it.

A Chokepoint Where Law Meets Power

The Strait of Hormuz is one of the most strategically important waterways in the world. A large share of global oil passes through this narrow corridor between Iran and Oman. Any disruption here affects not just regional actors but the global economy. In recent developments, tensions involving Iran, the United States, and Israel have turned this passage into a legal and military flashpoint. Ships have been detained, attacked, and escorted by naval forces. These incidents raise a basic but urgent question: what does international law actually allow in such a situation? Iran has not established a lawful blockade of the Strait of Hormuz. But its actions still create serious risks for commercial shipping. These risks arise not only from military escalation, but from disagreement about the law itself.

Why the Strait Matters in Law

To understand the dispute, we must begin with a simple point: not all sea routes are treated equally under international law. The Strait of Hormuz is an “international strait.” This means it connects two larger bodies of water and is used for global navigation. Because of its narrow width, the territorial waters of Iran and Oman overlap. As a result, ships cannot pass through without entering coastal State waters. Normally, States control their territorial waters. But international straits are different. Because they are vital for global trade, international law limits how much control coastal States can exercise. The key issue is what kind of navigation rights apply.

Two Competing Rules of Passage

At the heart of the dispute are two legal regimes: transit passage and innocent passage. Under the United Nations Convention on the Law of the Sea, international straits are governed by transit passage. This is a strong and practical rule. It allows ships and aircraft to move through the strait without delay. Submarines can stay underwater. Aircraft can fly overhead. Most importantly, coastal States cannot suspend this right. Transit passage reflects a simple idea: no single State should be able to choke a global shipping route. Iran rejects this framework. It argues that the Strait of Hormuz is governed instead by innocent passage. This rule is narrower. Ships must comply with stricter conditions. Submarines must surface. Overflight is not allowed. Coastal States can intervene if they believe their security is at risk. This is not just a technical disagreement. It is about control. If innocent passage applies, Iran has far greater authority over who can pass and how.

What Is Happening in Practice

Iran’s actions in the strait reflect this claim to greater control. It has detained vessels, cited navigational violations, and responded forcefully to perceived threats. Incidents such as the seizure of the Stena Impero show how legal arguments are used alongside strategic action. At the same time, the United States has considered escorting commercial ships through the strait. This may seem like a solution, but it creates new problems. Under the San Remo Manual, ships sailing under military escort can be treated as part of a military convoy. This could make them lawful targets. In other words, measures meant to protect shipping may actually increase the danger.

When Civilian Ships Become Targets

Modern naval warfare blurs the line between civilian and military objects. Under widely accepted legal principles, an object can be targeted if it contributes to military action and offers a clear advantage if destroyed. This has serious consequences in the Strait of Hormuz. Oil tankers, for example, may carry fuel that supports military operations. Cargo ships may transport goods with strategic value. Even indirect links to military supply chains can matter. The result is uncertainty. Ships that appear civilian may be treated as military targets in practice. For commercial operators, this creates a legal and operational risk that is difficult to manage.

Is Iran Imposing a Blockade?

Given these developments, it is tempting to describe Iran’s conduct as a blockade. But legally, that would be incorrect. A blockade must be effective. This means the State imposing it must be able to prevent all access to a coastline. The Strait of Hormuz remains open. Ships continue to pass, even if under threat. Iran is interfering with navigation, but it is not fully controlling it. This distinction matters. Calling the situation a blockade would give it a level of legal clarity that does not exist.

The Real Problem: A Legal Grey Zone

The deeper issue is disagreement about the rules themselves. Many States rely on UNCLOS and insist on transit passage. The United States goes further and argues that transit passage is part of customary international law, binding on all States. Iran disagrees and continues to assert innocent passage. This creates a legal grey zone. The rules change depending on who you ask. For ships in the strait, this is not an abstract debate. It affects how they are treated, what risks they face, and how conflicts may escalate. Law, in this setting, does not settle disputes. It becomes part of the dispute.

Why This Matters Beyond Hormuz

The situation in the Strait of Hormuz is not unique. It reflects a broader challenge in international law. When major powers disagree on fundamental rules, legal regimes begin to fragment. This has two consequences. First, it weakens predictability. States and private actors cannot rely on a single, stable framework. Second, it increases the role of power. Legal arguments are used strategically, not just normatively. For the development of legal science, this raises an important question: can international law still function as a common language when its basic rules are contested?

Conclusion: Law Under Pressure

Iran has not established a lawful blockade of the Strait of Hormuz. But that does not mean the situation is legally stable. On the contrary, it reveals how fragile the legal order can be in times of conflict. The real issue is not simply what Iran is doing. It is that States no longer agree on the rules that govern such actions. Transit passage and innocent passage are not just legal doctrines, they are competing visions of control. In this environment, the law does not stand above politics. It operates within it. And in the Strait of Hormuz, that means uncertainty is not an exception. It is the defining feature.

Zitiervorschlag: Hussain, Md Muneeb, Navigating Conflict: Legal Dimensions of Iran’s Control over the Strait of Hormuz, JuWissBlog Nr. 31/2026 v. 02.04.2026, https://www.juwiss.de/31-2026/.