The U.S. seizure of an oil tanker off the coast of Venezuela on Dec. 10 has generated a good deal of political and legal discussion. Until more information is available, however, it remains difficult to assess the legality of the operation. While the boarding was likely lawful under established international law, the seizure of the ship presents a more challenging set of unsettled questions.
What is known is that a U.S. Coast Guard specialist law enforcement detachment, reportedly in conjunction with FBI and Homeland Security Investigations (HSI) agents, conducted a fast rope boarding from a U.S. Navy Seahawk helicopter of the Skipper, a very large crude carrier. The vessel was carrying 1.6 million barrels of Venezuelan crude when the U.S. seized it. The vessel is now in U.S. custody, and forfeiture processes are apparently underway with respect to the cargo, as the warrant indicates. The Skipper is said to be part of the “ghost armada,” or the “shadow” or “dark fleet,” a group of ships engaged in illegal operations, oftentimes in an attempt to circumvent sanctions.
The Trump administration has put forward different justifications for the Dec. 10 seizure. First, it increased U.S. pressure on the regime of Nicolás Maduro in Venezuela (noting the Trump administration’s highly questionable views about the existence of an armed conflict with some Venezuelan non-state actors and its ongoing pressure campaign). U.S. Attorney General Pam Bondi said the operation was based on the enforcement of a warrant related to U.S. sanctions in respect of Venezuelan and Iranian oil exports for which the vessel (then registered as “Adisa”) was specifically sanctioned in November 2022. Homeland Security Secretary Kristi Noem linked the seizure to the U.S. “war on drugs,” saying, it was “directed by the president to ensure that we’re pushing back on a regime that is systematically covering and flooding our country with deadly drugs and killing our next generation of Americans.” All of these justifications relate to domestic law authorizations and enforcement powers, or to political considerations.
By contrast, the international law basis of the boarding and seizure has not, it seems, been directly and clearly addressed by U.S. authorities to date. That said, the Guyana Chronicle, a newspaper owned by the Guyanese government, reports that “the Government of the United States recently informed [the Guyana Maritime Administration] that the Motor Tanker SKIPPER … IMO Number 9304667, was spotted in international waters falsely flying the Guyana flag.” That is, it is possible that U.S. authorities did present an international law basis for boarding the tanker to the Guyana authorities at the time of the seizure because it was effectively stateless.
For now, we can surmise that the international law authority that has probably been employed to carry out the boarding is the UN Convention on the Law of the Sea (UNCLOS) Article 110(1)(d) right of visit in respect of a ship “without nationality.” Here, we will outline the preconditions for the boarding, and then assess the more contentious issue of the options for continued exercise of jurisdiction if this is indeed the international law basis for the boarding. We will not deal with the validity of the U.S. autonomous sanctions as a justification apart from noting – as have several other scholars – that the absence of a U.N. Security Council Chapter VII “all necessary means” sanctions resolution does call this legal basis into question as a matter of international law (but probably not U.S. domestic law). We will also not examine why the boarding and seizure is not, as the Venezuelan government and others have claimed, an incident of piracy, except to say that piracy is not– by definition and by operation of UNCLOS Articles 101-107– applicable in this case.
The Preconditions for a “Right of Visit” Boarding
Essentially, the proper and legitimate exercise of the right of visit, which is where a warship or other appropriately authorised government vessel can stop and board a foreign merchant vessel without flag State consent, requires the following: the right enforcing unit; the right place; the right trigger.
The right enforcing unit
The unit and personnel exercising the right of visit must deploy from a warship or naval aircraft, or from “other duly authorised ships or aircraft marked and identifiable as being on government service” (UNCLOS Article 110(5)). In this case, the helicopter was a U.S. Navy Seahawk, deployed from the USS Gerald R Ford aircraft carrier, and the law enforcement agents were Coast Guard, FBI, and HSI. Therefore, the precondition for a valid exercise of the right of visit was clearly met in the Skipper boarding.
The right place
This requirement concerns where the boarding took place. On the information available, the boarding happened outside the territorial sea of any State, in the Caribbean Sea area. The Guyana Chronicle reported that the United States informed the Guyana Maritime Administration Department that the vessel was in “international waters.”. The Guardian placed the location of the boarding roughly south-southeast of St. Vincent and The Grenadines and east of Grenada (perhaps around, using the scale on The Guardian chart, 50-ish nautical miles). If this is broadly accurate, then the boarding probably took place somewhere in the northeast part of the Grenada Exclusive Economic Zone, or perhaps in the south-southeast part of the St. Vincent and The Grenadines EEZ.
If this is correct, then the boarding happened outside the territorial sea of any State, and this is the key issue. The fact that it may have taken place in a third State’s EEZ is of no consequence. This is because the Article 110 right of visit applies in the high seas, but also – by virtue of UNCLOS Article 58(2) – in EEZs (beyond the territorial sea). There is no merit to any argument that the right of visit is in some way limited by any EEZ due regard obligation because this right has nothing to do with the coastal state’s EEZ rights and therefore its exercise is “not incompatible with” the EEZ regime.
The right trigger
In this case, the most robust available authorization for an Article 110 right of visit to board the Skipper is that there were “reasonable grounds for suspecting” that it was a vessel without nationality. There are three broad types of vessels without nationality implicated in UNCLOS. The first is where a vessel has no nationality because it has no registration, or because its claimed registration has been rejected by the relevant State. This is most likely the situation with the Skipper when she was seized, noting the statement of Guyana’s Maritime Administration Department that the vessel was “falsely flying the Guyana Flag as it is not registered in Guyana.” Indeed, it is reported that Guyana had “de-listed” the vessel (that is, removed it from the registry of ships entitled to claim Guyanese nationality) and reported this to the International Maritime Organization soon after it was sanctioned by the U.S. Treasury in 2022. That is, the vessel claimed a nationality it was not entitled to and so it was in fact a vessel without nationality and thus liable to the right of visit by the United States (or any other country, for that matter).
The second possible catalyst for “statelessness” is where the vessel claims the nationality of a State that is not recognized. The classic example is the 1948 Aysa case, intercepted in the high seas off of the Mandate Territory of Palestine in 1946 by a British warship. The Aysa initially flew no flag, then subsequently displayed a Turkish flag and later a “Zionist” flag (which is the Israeli flag today). The United Kingdom’s Privy Council ultimately determined that by flying a Zionist flag, the Aysa was flying an illegitimate flag that was not within the comity of nations (noting that the State of Israel was not declared until two years later) and that it was therefore stateless. This situation does not apply to the Skipper.
The third most common possibility for characterization as a vessel without nationality is by way of UNCLOS Article 92(2). This rule states (as is most likely relevant in this case) that where a ship “sails under the flag of two or more nationalities, claiming them according to convenience, the ship can be assimilated to a ship without nationality.” This could have potentially applied in the Skipper case, noting the varying reports about flag changes, although it is difficult to ascertain on the currently available information.
Although these are the legal typologies that underpin the right of visit for statelessness, the practical, real-world signs that trigger the right are by contrast not as strictly defined. There are many such operational indicators, including flying no flag or flying a suspected false flag, as well as intelligence such as contrary registry information. This is likely why the U.S. authorities communicated with Guyana – to check the Skipper’s registration. So in this case, the immediate indicia (as noted above) was likely that the vessel was flying a false flag: the flag of Guyana, which it was not entitled to fly given that the Guyanese authorities confirmed that it was not registered by them.
One interesting issue that is presented by this case, however, is the implication of spoofing a different identification on the maritime automatic identification system (AIS). Transmitting on AIS discloses, amongst other things, a vessel’s identity, and so the question is whether this electronic equivalent of a false flag (e.g., transmitting an identification which claims a flag different from the one it is physically flying) meets the Article 92(2) threshold of sailing “under the flag of two or more nationalities.” It is our view that it does, but that is an essay for another time. Still, on the basis of having the right enforcing unit, the right place, and the right trigger, it would seem pretty uncontroversial that the U.S. boarding of the Skipper was a legitimate exercise of the Article 110 right of visit.
The Scope of “Follow On”Jurisdiction
The more difficult and contentious issue is what happens after boarding and the scope of jurisdiction that can be enforced by the United States subsequent to an Article 110 boarding. This question of authority is not as clear for the vessel without nationality trigger as it is for the other Article 110(1) triggers for the right of visit. Nor is it simply a case of applying the same rule to a vessel without nationality visit as for the other triggers, because Article 110, along with some other UNCLOS provisions, discloses different specific jurisdictional grants depending on the specific trigger. That is, four of the five right of visit triggers are accompanied by relatively clear and concise grants or limitations as to follow-on jurisdiction, and it is worth noting these so that the contrast with the vessel without nationality trigger is made clear.
If the right of visit is triggered by a reasonable suspicion of piracy (Article 110(1)(a)), then the follow-on jurisdiction explicit in the law of the sea is extensive: seize and punish the vessel and the pirates (Article 105) by exercising universal jurisdiction. By contrast, if the trigger for the right of visit was suspicion that the vessel was engaged in the slave trade (Article 110(1)(b)), then the scope of jurisdiction includes making all the slaves on board free (Article 99), but the task of prosecuting the vessel and the slave traders falls primarily to the slave trading vessel’s flag State and the States of nationality of the individual slave traders. Similarly, if the trigger for the right of visit is unauthorized broadcasting (Article 110(10(c)), then follow-on jurisdiction – especially in relation to any prosecution – is specifically circumscribed via Article 109(3). Finally, if the suspicion is that the vessel is actually of the same nationality as the warship intending to conduct the visit (Article 110(1)(e) – sometimes called a “flag visit”), then the general international law of jurisdiction applies if the vessel is indeed of the same nationality as the visiting warship. If the suspicion is not borne out, however, then the visiting warship must leave as it has no jurisdiction, and compensation may be owed by that warship’s flag State (Article 110(3)).
With the Article 110(1)(d) “vessel without nationality” trigger, however, the grant of follow-on or substitute jurisdiction is not clear. The key question is, of course, how wide can this follow-on jurisdiction be, and can it include enforcement of boarding/ seizing state jurisdiction warrants and laws (see UNODC Ch15), as is the situation (in a right of visit sense) in relation to the Skipper. Salvador Santino Regilme, a political scientist, told Al Jazeera that the “step from ‘right of visit’ to full seizure of ship and cargo sits in a grey zone that recent scholarship explicitly describes as a ‘jurisdictional lacuna’” rather than “a settled rule.” This would mean that even if the vessel does not have a nationality, the assertion of the boarding state’s own subsequent jurisdiction over the vessel, people, and cargo is unsettled and likely quite limited.
The broader view (which is the view of one of the authors – here, and here at pp 485-487) is that the absence of a flag State jurisdiction enlivens the right of the boarding State to assert either at selection of, or the full suite of, its own jurisdiction as applicable to ships flying that boarding State’s flag. This is necessary so that a jurisdiction is available to be exercised over the vessel, its cargo, and the people in it (noting that these people will also be subject to varying scopes of extra-territorial jurisdiction depending upon their States of nationality). For some States (see, for example, Indian Ocean Tuna Commission Resolution 16/05), this may be limited to ship-focused matters only, such as crew health and safety, seaworthiness, or fisheries jurisdiction. For other States, the grant of follow-on jurisdiction is more comprehensive, including for “all appropriate law enforcement actions” (NWP 1-14M (2022) para 3.11.2.3). On this approach, the application of follow-on jurisdiction in the form of execution of domestic law based sanction warrants, and seizure of cargo, is likely permissible as a matter of U.S. domestic law, but (noting the non-UNSC Chapter VII basis of the sanctions) equally likely to remain contentious as a matter of international law.
To conclude, based on the available information, it does seem that the boarding and initial seizure of the Skipper was, in international law terms at least, uncontroversially lawful as an exercise of the right of visit based on the vessel being without nationality. The degree to which that international law authority then permits the further exercise of expansive follow-on jurisdiction, however, is a more contentious question upon which States certainly differ.
