Hormuz and the limits of open navigation

The Strait of Hormuz has once again moved from geography to law.

The questions raised in my last analysis on jurisdiction and enforcement do not end there. They reappear, in a different form, in the waters of this narrow but critical corridor. The setting has changed. The underlying concern has not.

The Strait carries nearly one-fifth of global energy supplies. Its legal status is well established. Under the United Nations Convention on the Law of the Sea, it qualifies as an international strait governed by the regime of transit passage. Ships and aircraft are entitled to continuous and expeditious passage, and that right cannot be suspended or impeded. Even earlier law recognised that such straits could not be closed.

On paper, the position is clear. The Strait cannot be lawfully shut. Yet the present moment illustrates a different difficulty.

Despite heightened tensions and repeated threats, vessels continue to pass. Pakistan's own tanker has recently transited the Strait without incident. That fact is not incidental. It confirms that the Strait remains open, both in law and in practice.

In legal terms, the threshold for closure is high. A blockade requires the actual prevention of passage. That condition is not met. The Strait has not been closed.

The pattern that emerges is not one of indiscriminate disruption, but of selective control. Certain vessels continue to pass, often subject to coordination or tacit clearance, while others face heightened risk. This is not the abandonment of legal structure. It is its managed navigation; pressure calibrated rather than declared.

The more relevant question, therefore, is not whether the Strait has been closed. It has not. The question is whether it can be made unreliable without being formally closed at all.

International law is structured around defined categories: transit passage, innocent passage, blockade and neutrality. Each carries its own rules and thresholds. What it does less effectively is address conduct that operates below those thresholds while producing similar consequences.

Navigation does not depend solely on legal entitlement. It depends on risk. Mines do not need to be widespread to be effective. The seizure of even a limited number of vessels, or the credible threat of such action, can raise insurance costs and deter passage. At that point, the Strait remains legally open but practically uncertain.

This is not a clear breach of the law. It is conduct at its margins; avoiding formal violation while shaping outcomes.

That distinction is precisely where the strain lies. When outcomes begin to mirror what the law prohibits, without formally crossing the line, the system is not openly defied but quietly tested.

It also reflects a shift in how power is exercised. Instead of confronting legal rules directly, states increasingly operate around them, preserving formal compliance while recalibrating practical realities. The result is not the absence of law, but a change in how its limits are understood and applied.

The distinction matters. A formal closure would engage clear legal consequences under both the law of the sea and the broader prohibition on the use of force. What is emerging instead is more calibrated: pressure that avoids formal classification while influencing behaviour.

This is not unfamiliar. During earlier conflicts in the Gulf, disruption was achieved through risk rather than declaration. The law remained formally intact. The conditions of navigation did not.

For states that rely on the predictability of legal rules rather than the projection of power, this distinction is not academic. Legal guarantees are only meaningful to the extent that they can withstand pressure.

Where conduct avoids formal breach while undermining practical use, the protection becomes thinner, not by violation but by erosion.

The Strait remains open. The law remains in place.

The question, as before, is whether either continues to matter when it matters most.