The UN Convention on the Law of the Sea: Why the U.S. Hasn’t Ratified It and Where It Stands Today

By: Iosif Sorokin |

The UN Convention on the Law of the Sea (UNCLOS III) set down international norms governing the use of the world’s oceans and their resources by states. Also known as the Law of the Sea Treaty, UNCLOS III replaced two prior attempts in 1956 (UNCLOS I) and 1960 (UNCLOS II) to define the rights of states with respect to their territorial seas, continental shelves, use of the high seas, and management of marine natural resources. Since its adoption in 1982, 167 states have joined the treaty, including Russia, China, and the European Union. But despite its acceptance in much of the world, the U.S. has not joined the treaty, with the most recent ratification attempt failing to get the requisite two-thirds of votes in the Senate.

Supporters of the treaty trumpet its widespread approval among the U.S. business community, environmental groups, and the military, which they say makes it an easy choice for ratification. But critics argue that it is a flawed and unnecessary treaty that threatens US sovereignty. Recent international disputes over territorial seas implicating the treaty have affirmed its importance for international law today, making America’s absence from it all the more significant. They also raise the possibility that refusal to join the treaty could have adverse affects on America’s interests at sea.

Support for UNCLOS III

A broad range of U.S. business interests back the Law of the Sea Treaty, including major oil, fishing, shipping, and telecommunications companies. One of the major features of the treaty is that it gives a state exclusive control over natural resources and economic activities within a 200-nautical mile zone extending from its shoreline. This “Exclusive Economic Zone” (EEZ), as it is aptly termed, would provide clear legal rights to U.S. companies to explore and exploit resources in the largest EEZ in the world, containing 3.4 million square miles of ocean. For this reason, the President of the U.S. Chamber of Commerce, in testimony before the Senate Committee on Foreign Relations, unequivocally supported ratification of the treaty, stating that it would provide “American companies the legal certainty and stability they need to hire and invest.”

Environmental groups also support the Law of the Sea treaty because it calls on all states to protect and preserve the marine environment and to prevent pollution of the oceans. It also gives states jurisdiction over environmental protection and marine science research within their EEZ’s. By joining the treaty, environmental groups argue the U.S. could take a leading role in ocean conservation and preservation issues.

The other major support for the Law of the Sea Treaty comes from the U.S. military. The U.S. Navy has long supported the treaty as the best way to preserve navigational rights for its fleet, which is the largest in the world. The treaty grants innocent passage for all vessels on the high seas (parts of the ocean not controlled by any state) and, crucially, within a state’s territorial sea, defined as a zone twelve nautical miles from a coastal state’s low water line. Within this zone, a coastal state has sovereignty over the seabed, subsoil, and airspace. The treaty would provide a clear legal right for US ships to enter the territorial seas of other coastal states, which naval commanders argue is vital for national security. Indeed, support for the treaty is so universal among military leaders that six high ranking military officials testified before the Senate Committee on Foreign Relations in 2012 to support ratification of the treaty.

Opposition to UNCLOS

Despite its popularity, some critics argue that UNCLOS is seriously flawed and would detract from U.S. interests by ceding sovereignty to international organizations and tribunals. They argue that UNCLOS is unnecessary since customary international law and other agreements already provide the legal bases for international maritime law. For instance, these agreements already grant Navy ships the freedom to navigate on the high seas and no state has or would attempt to block passage of a US vessel through their waters, both because of US naval supremacy and because they want reciprocal rights to sail through our seas. So ratifying the treaty would merely signal to other nations that the US can only secure its rights on the international stage by appealing to institutions favored by the rest of the world, thereby diminishing US sovereignty.

Critics also argue that the US should not bind itself to international bureaucracies, such as the International Seabed Authority (ISA) created by UNCLOS to regulate mining activities on the deep seabed beyond the jurisdiction of any country. These bureaucracies are often wasteful and hostile to US interests, and the ISA is particularly threatening since there is no veto for the U.S. Thus the ISA Assembly could potentially amend the treaty without the consent of the U.S.

Likewise, opponents of UNCLOS are adamant that joining the Convention would expose the U.S. to frivolous lawsuits for maritime activities, since it obligates parties to submit their disputes to a third-party for arbitration. They argue that the treaty would be a weapon for environmental activist to bring legal claims against U.S. companies and the Navy. Moreover, Article 296 of UNCLOS provides that judgments rendered in accordance with the Convention are binding on the parties involves and cannot be appealed, further infringing on U.S. sovereignty.


Although ratification of UNCLOS is unlikely today given staunch opposition to it in the Senate, the treaty remains an essential instrument of international law, particularly for resolving international maritime disputes. America’s abstention from the treaty is significant in this context, since as the preeminent naval power in the world it should hold a leading role in shaping the law of the sea. Instead, other nations are playing a larger role.

For example, the Philippines has taken a leading role in bringing an arbitration case against China over its infamous nine-dash line claim to the South China Sea. Although China has refused to take part in the proceedings, the International Tribunal on the Law of the Sea, established by UNCLOS, has proceeded with the case pursuant to the rules of the Convention. The U.S. State Department released an official report rejecting China’s claim, relying on portions of UNCLOS that it said reflect current customary international law. But custom and practice are malleable and subject to interpretation, which makes China’s refusal to adhere to the customary maritime zones problematic. China, along with other states, may soon push the law of the sea in new directions opposed by the U.S. Direct American participation in UNCLOS would alleviate this concern by affirming a clear legal basis for resolving maritime disputes.

UNCLOS is also vital to expanding conservation efforts in the oceans and allowing nations with Arctic coastlines to make legal claims to the oil and gas reserves that lie beneath the Arctic waters. Denmark, Norway, Canada, and Russia have already used UNCLOS to make legal claims to the Arctic Ocean and seabed. By abstaining from the treaty, the U.S. lacks official standing in these important initiatives, which are being taken advantage of by other nations.

Ultimately, whether efforts to ratify the Law of the Sea Treaty sink or swim in the U.S., it remains a crucial instrument of international maritime law, so lawyers in the U.S. must understand its implications for America’s interests at sea.