Two kinds of lawyer look at the same Ukrainian sea drone and reach opposite conclusions. One says the attack belongs to the laws of war and may well be lawful. The other says the 1982 sea convention rules it out. Attacks on tankers in late 2025 sharpened the dispute.
The war-law view
Wolff Heintschel von Heinegg, a professor of public international law, wrote in December 2025 about Ukrainian “Sea Baby” drone strikes on two Gambian-flagged tankers, the Kairos and Virat. His starting point was that an international armed conflict between Russia and Ukraine has existed since March 2014 and widened with the full-scale invasion of February 24, 2022. So the strikes, he argued, fall under the law of naval warfare, not under maritime law or sanctions enforcement.
That body of law lets a belligerent attack lawful targets anywhere outside neutral waters. They include warships, military installations, and merchant ships that make an effective contribution to enemy military action. A flag counts only as prima facie evidence of a ship’s character, he noted, and tankers in Russia’s “shadow fleet” could be treated as enemy vessels.
His conclusion was mixed. Ukraine could have captured the tankers. Sinking or disabling them with unmanned craft, with no effort to move the crews to safety, would not pass the test of prize law. Whether they were lawful targets at all depended on how military objectives are defined. Under the narrow definition in Additional Protocol I, he saw real doubt, because the contribution of oil exports to Russian military action is indirect. The United States takes a broader line, covering anything that sustains the enemy’s war effort. Most governments have not protested the Ukrainian attacks on Russian oil export infrastructure, he observed, which could amount to tacit endorsement.
The law-of-the-sea view
Yücel Acer, a professor of international law at Ankara Yildirim Beyazit University, reads the same events through the 1982 convention. Beyond territorial waters, the exclusive economic zones of Black Sea states are treated as high seas for navigation, where ships answer only to their flag state. Warships may step in against other states’ merchant ships only in a short list of cases, such as piracy, the slave trade, unauthorized broadcasting or statelessness. Even then, the tool is a “right of visit,” meaning stopping and boarding a ship, not shooting at it. He wrote that attacks on such vessels cannot be justified as self-defense, and that armed action inside a coastal state’s economic zone violates its sovereign rights.
A problem with the drones themselves
A third strand, from Charles Layne in January 2023, looked at Ukraine’s unmanned surface vessels after the October 29 attack near Sevastopol, which used seven of them. Under Article 91 of the convention, he wrote, a craft is a ship only if its state flags it. Ukraine had apparently not flagged its drones, so they were not ships. Without ship status, and then warship status, they could not lawfully exercise belligerent rights, and Ukraine would carry responsibility for a wrongful act under international law.
Sources
- The Ukrainian Attacks Against Gambian-Flagged Oil Tankers in the Black Sea (Articles of War, Lieber Institute West Point)
- Attacks on Merchant Ships in the Black Sea: What Law Says (Politics Today)
- Ukraine's Suicide Drone Boats and International Law (Articles of War, Lieber Institute West Point)
