No ordinary sea: who governs the Strait of Hormuz?
Which law governs the Strait of Hormuz? Under international law, both Iran and the US are expected to comply with the ‘Constitution for the Oceans’. In practice, the situation is more complicated, explains maritime law expert Hilde Woker.
An American blockade of the Strait of Hormuz, Iran seeking to levy a toll on shipping... Are such actions lawful? And which law applies to this vital waterway? Even for Hilde Woker, an assistant professor of public international law who specialises in maritime law, there are no easy answers. Because the Strait of Hormuz is no ordinary stretch of sea.
Territorial waters of Iran and Oman
The Strait of Hormuz falls within the territorial waters of Iran and Oman – under the international law of the sea, that is. This grants the two states specific rights and obligations. Coastal states enjoy full sovereignty of their territorial seas, with the exception of the requirement to allow ships of other states ‘innocent passage’.
‘The same principle applies to the Netherlands’, says Woker. ‘Anyone can pass through our waters, but they may not stop, fish or conduct research without permission.’
That was the easy bit. It becomes more complex when we look beyond the widely accepted law of the sea. The waters between Iran and Oman are a busy shipping route for oil and gas, upon which large parts of the world depend. At the same time, the Strait lies in a geopolitically volatile region, marked by the recent US attacks on Iran.
Not your ordinary sea
There are three reasons why the Strait of Hormuz is not your ordinary stretch of sea.
First, although Iran has signed the United Nations Convention on the Law of the Sea (UNCLOS), it has never ratified the treaty. As a result, it is not formally bound by the law of the sea.
Second, international straits have a separate status under the law of the sea. The right of passage is more extensive in international waters than in territorial waters and goes beyond the concept of innocent passage.
There are strong arguments for classifying the Strait of Hormuz as an international strait. ‘At its narrowest point, the Strait is 20 nautical miles wide, which meets the definition of an international strait set out in UNCLOS’, Woker explains. ‘That grants ships a greater right of passage in this strait and, by extension, restricts the extent to which coastal states can exercise control. Even if a ship enters territorial waters, the right of transit passage still applies’, says Woker.
However, because Iran has not ratified UNCLOS, there remains disagreement on whether Iran is legally obliged to observe these rules.
Law of armed conflict versus law of the sea
The third reason is that Iran and the United States are at war. This means that the law of armed conflict may come into play, and in certain situations, it can take precedence over the law of the sea. Under the law of armed conflict, a blockade of the Strait of Hormuz could potentially be justified, whereas it would not be permissible under the law of the sea.
Even here, it is hard to give a clear-cut answer, says Robert Heinsch, an associate professor of international law. ‘It is conceivable that the hostilities could be characterised as an international armed conflict. In principle, blockades are allowed in that context, but they are subject to restrictions. They must not be used to starve the civilian population or cause disproportionate harm.
‘Whether a blockade complies with the rules must be assessed on a case-by-case basis. Those imposing the blockade must also respect the rights of neutral states, which includes an obligation not to interfere with neutral shipping.’
Negotiations and mediation
If these rules are breached, the issue becomes one of state responsibility.
‘In national law, you have the police, the prosecution service and the judiciary’, says Woker. ‘Enforcement is far less automatic at the international level. States can bring cases before an international court, but only if all parties consent. Or they can impose unilateral measures such as sanctions or the suspension of diplomatic relations, but these are unlikely to be effective for either Iran or the US. Negotiation and mediation may offer the most viable way forward’, Woker concludes.