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How Ratifying UNCLOS Can Help the US Counter China’s Aggressive Activities and Unlawful Maritime Claims in the South China Sea

(Image via CNN)

The US State Department recently concluded that the People’s Republic of China’s (PRC) maritime claims in the South China Sea contravene international law under the 1982 United Nations Convention on the Law of the Sea (UNCLOS). Indeed, the PRC has baselessly asserted sovereignty over most of the Sea and leveraged such purported rights into environmentally damaging island construction projects—all of which violate UNCLOS, as determined by an international tribunal. The State Department’s analysis, however, suffers from one glaring piece of hypocrisy: The United States itself has yet to ratify the convention. Even though the United States participated in all UNCLOS negotiations from 1974 to 1982 and currently recognizes the treaty as customary international law, Republican circles have long stymied accession on the belief that it would compromise US sovereign power and do little to counter the PRC’s incursions in the South China Sea. Until the United States joins the 167 other nations, plus the EU, that have already ratified UNCLOS, its condemnations of the PRC lack credibility and fail to deter Beijing’s transgressions. The recent legislative push by Democratic members of congress to uphold UNCLOS thus presents a crucial opportunity for the country to strengthen its pushback against the PRC by aligning with the international community on a shared legal framework for maritime conduct. 

The PRC has consistently engaged in aggressive land reclamation projects in the South China Sea with detrimental environmental repercussions. Starting in 2015, the PRC began constructing artificial islands in the disputed archipelago of the Spratly Islands to serve as military outposts. The PRC has developed installations on these islands ranging from airstrips and ports, which extend the reach of its planes and ships, to radar facilities, which enhance its surveillance capabilities over the surrounding area. While the PRC’s militarization of the South China Sea evidently carries significant geopolitical and security implications for the adjacent nations, it has on a more immediate level harmed the nearby marine environment. The dredging process required for island building has destroyed many of the South China Sea’s coral reefs, which harbor the largest concentration of marine biodiversity on the planet. Dredging also creates plumes of sediment and corrosive sand, which mix with toxic contaminants from ships and block sunlight and oxygen from reaching underwater species. Scientists have quantified the scope of these plumes and the resulting decreases in absorption and chlorophyll levels, concluding that island building considerably damaged the biological health of the South China Sea. 

The PRC bases its activities in the South China Sea on historic rights to the region, but these claims violate international law under UNCLOS. Dating back to 1947, the PRC has insisted that the vaguely defined sector enclosed by a U-shaped nine-dash line running along the coasts of Vietnam, Malaysia, Brunei, Indonesia, the Philippines, and Taiwan falls under its domain. Specifically, the PRC asserted sovereignty over the features and waters within the line and historic rights over fishing, navigation, and resource development. A five-judge tribunal at the Permanent Court of Arbitration, however, unanimously and unequivocally invalidated the PRC’s nine-dash line and historic rights claims in 2016—three years after the Philippines initiated proceedings against the PRC to clarify their respective maritime entitlements. The tribunal determined that, “to the extent China had historic rights to resources in the waters of the South China Sea, such rights were extinguished to the extent they were incompatible with the exclusive economic zones provided for in [UNCLOS].” In other words, the Philippines’ sovereign rights in the exclusive economic zone granted by UNCLOS trumped whatever precedent the PRC had relied on. 

Furthermore, the tribunal commented on China’s island building operations, clarifying that the natural conditions of some of the maritime features on which they were erected prohibited them from ever being officially classified as islands with their own exclusive economic zones. The PRC received censure for “caus[ing] severe harm to the coral reef environment and violat[ing] its obligation to preserve and protect fragile ecosystems and the habitat of depleted, threatened, or endangered species” given its ratification of UNCLOS (among other ostensible environmental commitments). 

The PRC, which refused to participate in the tribunal’s proceedings from the beginning, unsurprisingly rejected the above conclusions in a white paper reiterating its South China Sea claims. While this revised articulation did not allude to the nine-dashed line, the PRC asserted sovereignty over four main groups of islands and maritime features and declared exclusive economic zones around them. Drawing on familiar justifications rooted in historic rights, the PRC based its “territorial sovereignty and relevant rights and interests in the South China Sea” on the contention that “China is the first to have discovered, named, and explored and exploited [the maritime features] and relevant waters, and the first to have exercised sovereignty and jurisdiction over them continuously, peacefully, and effectively.” Subsequent notes verbales from the PRC to the Secretary-General of the UN between 2019 and 2021 showed the PRC continuing to appeal to “the long course of historical practice,” “historic rights,” and “abundant historical and legal evidence” to uphold its aggressive activities in the South China Sea. In some communications, the PRC even went so far as to argue that it was acting in accord with UNCLOS and all relevant international law.

The United States under both the Trump and Biden administrations has, in alignment with the tribunal’s decision, objected to the PRC’s maritime claims in the South China Sea on the grounds that they violate international law. Such denunciations, however, lack credibility given that the United States has still not ratified UNCLOS despite having participated in its formulation. Republicans like Senator Rob Portman of Ohio, who voted to prevent ratification in 2012, have for years harbored concerns that UNCLOS would inhibit US interests abroad and expressed skepticism about international bodies’ ability to enforce its provisions. In the case of the PRC’s South China Sea claims, this mindset is counterintuitive and defeatist. US military leadership supports ratification, as evidenced by recent confirmation hearings. Commandant of the US Coast Guard, Admiral Karl Schultz gave his “full-throated” approval, while Vice Chairman of the Joint Chiefs of Staff Admiral Christopher Grady identified that the US “undermines [its] leverage by not signing up to the same rule book which we are asking other countries to accept.” 

A newfound push by Democratic members of Congress to ratify UNCLOS presents a pivotal opportunity for the United States to bolster its opposition to the PRC’s spurious maritime claims in the South China Sea. In February, the House passed a motion expressing that it was in US national interest to ratify UNCLOS in light of the PRC’s increasingly disruptive operations. As Representative Ami Bera, a cosponsor of the amendment and Chairman of the House Subcommittee on Asia, the Pacific, Central, and Nonproliferation, articulated, “Ratifying UNCLOS strengthens [US] ability to support [its] allies and partners in advancing a free, open, secure Indo-Pacific, and gives the United States more leadership and credibility as [it] continues to fly, sail, and operate wherever international law allows.” Ratification would require President Biden’s support, a vote of approval from the Senate Foreign Relations Committee, and 67 votes out of an evenly divided Senate. While the latter seems an impossible feat, Biden would do well to advocate the importance of UNCLOS, for the issues of the South China Sea go beyond mere territorial spats. Rather, they pertain to broader national priorities of promoting a rules-based maritime order, protecting marine environments, and emphasizing international solidarity in a time of conflict and upheaval.