The US Navy intercepted and seized the Iranian-flagged cargo ship Touska in the Gulf of Oman on April 20.
The USS Spruance damaged the Touska's engine room after the ship allegedly ignored warnings for six hours.
The US claims the seizure was lawful enforcement of its blockade on Iranian ports, in place since April 13.
Iran has condemned the blockade and the ship's seizure as "acts of piracy".
The legality hinges on whether the US and Iran are in an active state of armed conflict or if the April 8 ceasefire is legally binding.
Detailed Insights:
The US-Israeli alliance initiated conflict with Iran on February 28, leading to Iran effectively closing the Strait of Hormuz.
A ceasefire was implemented on April 8, but the US later announced a naval blockade to restrict Iran's oil exports, prompting retaliatory actions from Iran.
The legal framework governing the situation depends on the "status" of the conflict and the geographic coordinates of the US blockade, which remain undisclosed.
The 1982 UN Convention on the Law of the Sea (UNCLOS) governs peacetime activities, while the Law of Active Combat (LOAC), or International Humanitarian Law, applies during international conflicts.
If the ceasefire is not legally binding, the US may argue that the blockade is a lawful resumption of hostilities under the LOAC.
If the ceasefire is legally binding, the US actions would be illegal under UNCLOS, which guarantees commercial ships the "freedom of the high seas" and does not allow for unilateral enforcement of economic sanctions.
In wartime, the San Remo Manual grants belligerent warships the right to visit and search merchant vessels and capture enemy-flagged vessels.
Prize law allows the US to bring the Touska before a domestic Prize court to legally transfer the title of the ship and its cargo, though this hasn't been done since World War II.
Key Concepts Involved:
UNCLOS: An international agreement that establishes a legal framework for all marine and maritime activities.
LOAC: A set of rules that seek to limit the effects of armed conflict for humanitarian reasons.
San Remo Manual: A universally recognized code governing naval warfare and the capture of property at sea.