The dramatic seizure of the Russian-flagged tanker Marinera/Bella 1 in the north Atlantic, carried out by the US coastguard with British support, underscores the collision between maritime law and power politics.

Under the United Nations Convention on the Law of the Sea (Unclos), ships on the high seas enjoy freedom of navigation and fall under the exclusive jurisdiction of their flag state. (However, boarding a vessel without consent is lawful in exceptional cases such as piracy, statelessness, hot pursuit or under a UN mandate.)

The US has justified the operation through domestic sanctions law and a federal warrant. These sanctions were part of a broader US oil-export blockade targeting shipments of Venezuelan crude, specifically sanctioning tankers involved in transporting oil for the Venezuelan government and affiliated entities. They were not directed at Russia generally.

The US and the UK emphasised the vessel’s “statelessness”. Indeed, the tanker’s mid-voyage switch to a Russian flag raises questions about the regularity of its re-registration.

Under maritime law, fraudulent reflagging is a violation that can render a vessel stateless and open the door to enforcement. In this case, this position is obviously contested by Russia, which claims that a proper re-registration happened.

Moscow’s protest and reported naval shadowing – Russia reportedly dispatched a submarine and at least one surface vessel in proximity but did not engage – highlight........

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