UNCLOS III provides that, if a ship or its crew are seized on the high seas, the flag state can appeal to the International Tribunal for the Law of the Sea (ITLOS) in Hamburg, Germany, for a prompt decision on the legality of the seizure.³ The treaty allows states to opt for other forms of arbitration on other disputes, but other forms of arbitration require all nations involved to agree on a specific panel of arbitrators. The only important category of dispute where one party can force another to answer before ITLOS is when a ship has been detained on the high seas and the complaining party seeks its immediate release.

Seizing a ship on the high seas without the consent of its home government would inevitably trigger a diplomatic confrontation. But in the right circumstances, the United States or its allies might feel obliged to act first and try to handle the diplomatic protests later. If intelligence gives reasonably firm indications of an imminent terror attack to be launched from a particular ship, the U.S. could insist on intervening, claiming a right of self-defense that supersedes the general “rules of the road” at sea. Alternatively, the United States might claim that a ship operated by terrorists was so closely analogous to a pirate ship that intervention could be justified under the UNCLOS exemption for piracy. In still another variant, the United States might interpret a bilateral agreement with the flag state as covering a particular intervention, while the flag state insisted on a different interpretation. In any of these cases, the flag state would likely sit on the sidelines while the ship’s operators pursued a claim on their own initiative, “on behalf of the flag State,” as UNCLOS allows.⁴ It is easy to imagine situations in which U.S. intervention might trigger a complaint to ITLOS. It is hard to imagine situations in which ITLOS would be other than a complicating factor in ensuing U.S. diplomacy toward the flag state.

Similarly, counter-proliferation efforts at sea are hindered by UNCLOS Article 92, which provides that “ships sail under the flag of one state only and, save in exceptional cases expressly provided for in international treaties or in this Convention, shall be subject to its exclusive jurisdiction on the high seas.” That means that a warship must have the consent of the flag state or the master to board and search a foreign flag vessel encountered seaward of the territorial sea of another nation. The enforcement regime established in both UNSCRs 1718 (2006) and 1874 (2009), which ban most arms transfers to and from North Korea, is based on exclusive flag state jurisdiction. Although UNSCR 1874 contains an enhanced maritime cargo inspection regime, it is still dependent on flag state consent (Operative Paragraph 12). UNSCRs 1696 (2006), 1737 (2006), 1747 (2006) and 1803 (2008), which impose a similar ban on material related to Iran’s nuclear weapons program, are likewise based on flag state jurisdiction. Interdiction efforts on the high seas under other non-proliferation initiatives, like the 2005 Protocol to the Convention for the Suppression of Unlawful Acts against the Safety of  Maritime Navigation (SUA)¹⁹ adopted by the International Maritime Organization (IMO) and the Proliferation Security Initiative (PSI)²⁰ announced by President Bush in March 2003 to combat the growing threat of WMD proliferation, also suffer from the same weakness – they are based on flag state consent. It is highly unlikely that Iran or North Korea will give consent to a foreign warship to board one of its vessels at sea. In short, in could be argued that UNCLOS allows North Korea and Iran to transport WMD-related materials with impunity, hiding behind the concept of exclu- sive flag state jurisdiction on the high seas.

Far from treating such seizures as remote hypotheticals, the Bush administration has invested considerable effort in a "Proliferation Security Initiative" (PSI) under which the United States has signed agreements with states that provide flags for most of the world's commercial shipping. These agreements may strengthen U.S. claims to intercept suspicious ships on the high seas, when flying with markings from the most common flagging states (such as Belize, Panama, and Libya, which have all signed such agreements). But the PSI agreements do not make clear when or whether ships or crews may be subject to long-term detention, and all the agreements stipulate that they do not supersede accepted standards of international law.

If we ratify the Law of the Sea treaty, even a PSI agreement with the flag state won't necessarily keep a dispute about the seizure from winding up before the Law of the Sea tribunal in Hamburg. That tribunal has asserted its right to hear claims for "prompt release" when filed by owners or operators of a ship, even when the nominal flag state takes no role in the proceedings. In past cases, ITLOS has ruled that ships cannot be detained, even when claimants refuse to supply full information about how the ship was acquired and on whose behalf. So while we have jealously reserved the right to detain terror suspects captured on land, we will, if we ratify this treaty, give up our right to decide when we can hold terror suspects seized at sea.

PSI is not compatible with LOST, despite proponents’ claims to the contrary. As a treaty, LOST is binding international law on the parties, whereas PSI is only an informal arrangement between certain nations, and carries no force as international law. The argument that PSI can be executed within the rules of LOST, even though LOST clearly prohibits boarding actions critical to PSI, ignores the fact that LOST outranks PSI in the hierarchy of international law.

As a result, unless one or more of the Treaty-approved circumstances for an at-sea intercept applies, LOST member states could be precluded from participating in such an action – even when there might be compelling evidence that nuclear or other WMD or their delivery systems were on board. As long as the United States continues not to be a LOST state party, it can always act unilaterally. That option, however, will be foreclosed, and our security possibly endangered as a result, if the Senate consents to the Treaty’s ratification.

In this connection, it must be noted that the Chinese and Russians have strenuously objected to the Proliferation Security Initiative, claiming that it violates LOST. They can be expected to seek mandatory dispute resolution of the matter should the United States become a state party. Should the ruling go against us, a critical tool in the nation’s effort to prevent the spread of nuclear, chemical and biological weapons and their delivery systems could be lost for good.