With the world’s most powerful Navy and largest exclusive economic zone (EEZ), the United States is arguably the leading maritime nation. Yet the United States has failed to join the United Nations Convention on the Law of the Sea (UNCLOS), the “Constitution of the Oceans” that codifies key principles for freedom of navigation, rule of law, and environmental issues for more than 70 percent of the earth. Since it opened for signature in 1982, a vocal minority of strident senators have thwarted U.S. ratification. Nevertheless, UNCLOS accession enjoys the support of a remarkably diverse coalition of American military, environmental, and industry leaders. As the United States resets its global agenda, it’s finally time to join the Law of the Sea Convention.

Indeed, the recent U.S. submarine deal with Australia highlights the importance of UNCLOS. As these nuclear submarines are built and delivered, they will serve as a counterweight to China’s excessive maritime claims, and uphold maritime rule of law and freedom of navigation – as enshrined in the law of the sea.

Today, 167 states and the European Union have joined UNCLOS, a testament to the treaty’s status and broad international acceptance. The U.S. absence at the table is more perplexing than ever, considering the emergence of three issues that will define international maritime governance in the 21st century. I label these issues the “Three Cs of Law of the Sea” – (1) China, (2) climate change, and (3) credibility. These three issues are coming into clearer focus as the United States resets its foreign policy and security posture after the post-9/11 era.

1. China. China’s maritime claims over an enormous swath of the South China Sea, based on an anachronistic “Nine-Dash Line,” are well-known. China invests enormous resources in building up contested “rocks” and “low tide elevations” into artificial islands. These excessive maritime claims are antithetical to core law-of-the-sea navigational provisions, maritime delineations, and sovereignty claims. This view was reaffirmed in the 2016 Permanent Court of Arbitration (PCA) decision in Philippines v. China, a resounding defeat for China’s legal claims in the region. But China dismissed the PCA’s ruling, arguing that the international tribunal lacked jurisdiction over the matter. The United States is quick to point out that China agreed to submit to the PCA’s jurisdiction in accordance with Article 287 of the convention. China brushes aside any such criticism, noting the U.S. status as a non-party. Meanwhile, China’s South China Sea buildup continues apace, and China has refused to back down from its claims.

Earlier this month, a U.S. Navy destroyer, the USS BENFOLD, conducted a freedom-of-navigation operation in the South China Sea, challenging China’s maritime claims at Mischief Reef. And China recently took another step in its maritime brazenness by updating its 1983 “Maritime Traffic Safety Law.” This revision requires foreign vessels “to inform maritime authorities, carry relevant permits and submit to China’s command and supervision.”  This law applies to all Chinese territory, both inside and outside the South China Sea.

While it remains to be seen how this traffic safety law will be implemented, it is inconsistent with core navigational principles codified in UNCLOS. And the South China Sea could serve as a proxy for a larger conflict between the United States and China, a point chillingly made in the recent, bestselling novel “2034” by Admiral (ret.) James Stavridis and Elliot Ackerman. Indeed, while the United States was fighting wars in the Middle East, China developed the largest navy in the world by size, with a force of 350 ships and submarines (the U.S. has 293).

U.S. accession to UNCLOS will not “solve” the South China Sea crisis, but doing so reaffirms the U.S. commitment to freedom of navigation in the region and positions the United States to meet the strategic competition with China. In accompanying U.S. diplomatic protests to China’s excessive claims, the United States highlights the importance of the principles enshrined in the Law of the Sea Convention. Last year, the State Department stated that the United States “stands with the international community in defense of freedom of the seas and respect for sovereignty.” The obvious question:  If these maritime principles are so important, why doesn’t the United States reaffirm them by joining UNCLOS?

2. Climate change. Climate change is fundamentally reshaping the ocean’s physical environment, resulting in a host of unresolved issues. The United States has rejoined the Paris Climate Accord, but there is now a convergence of unresolved maritime and climate governance issues where U.S. leadership is needed.

Consider the Arctic, a region that is warming at two to three times the rate of the rest of the planet, opening up trade routes and the possibility for natural resource extraction. The U.S. Alaskan continental shelf claim may extend out to 600 nautical miles, but as a non-party to UNCLOS, the United States is likely prohibited from making a submission to the Continental Shelf Commission, a key UNCLOS technical body that helps determine the scope and limitation of each nation’s continental shelf. Meanwhile, every other Arctic coastal state (Canada, Denmark, Russia, Norway) has joined UNCLOS. Not surprisingly, they have all made continental shelf submissions. Russia asserts a continental shelf that borders Alaska’s and extends to the North Pole via Lomonosov Ridge. By some estimates, the extended U.S. continental shelf is the size of two California’s, a source of untapped economic potential. As the United States sits on the sidelines, Russia can rejoice at the unforced error and the resulting inability of the United States to avail itself of the Continental Shelf Commission.

In addition, climate change is raising a host of emerging questions that strike at the core of maritime governance. Consider: How will sea-level rise shift maritime boundaries and what law will apply to shifting territorial seas? Are nations prepared for climate refugees fleeing small island developing states in the Pacific? What can be done to stop the devastating impacts to the loss of the world’s coral reefs? What is the legal framework to address carbon sequestration efforts on the high seas? And is the world prepared for potential “green swan” events that could lead to environmental devastation to coastal states and possible nation extinction? Clearly, the United States needs a seat at the table to help shape, lead, and manage the convergence of climate change and law-of-the-sea issues this century.

3. Credibility. The Biden administration has stated that one of its goals is to demonstrate that U.S. democracy works, with the express purpose of restoring U.S. credibility on the world stage following the attacks on domestic and international institutions in recent years. UNCLOS ratification offers a ready-made opportunity to vindicate democratic governance while bolstering U.S. credibility on the world stage. The 2004 Senate Foreign Relations Committee voted 19-0 in support of joining the convention, and in 2007, the committee – chaired by then-Senator Joe Biden – voted 17-4 to ratify the treaty. President George W. Bush was willing to sign it, but it languished in the Senate due to a small group of senators who vowed to use every procedural gambit to block U.S. accession. Senators argued that the United States would not be able to decide what constitutes a “military activity,” a term not clearly defined in UNCLOS. But the United States can easily make a written declaration upon signing, to reinforce that no international tribunal would define U.S. military activities.

A similar effort was scuttled in 2012 following a vigorous lobbying effort from conservative groups that cited concerns the United States was ceding sovereignty to an international organization. Yet joining UNCLOS would codify and reaffirm U.S. sovereign rights over its own EEZ and continental shelf, a point made by John Bellinger, the State Department’s legal adviser in the Bush administration.

My former boss in the U.S. Navy (and former Pacific Commander), Admiral Harry Harris, testified to the House Armed Services Committee in 2016, “I think that in the 21st century our moral standing is affected by the fact that we are not a signatory to UNCLOS.” That statement rings true today. Critics have suggested the United States does not need to join UNCLOS because its main provisions reflect – and thus are already covered by – customary international law. But customary international law can shift over time. And reliance on customary international law alone does not provide the United States a seat at the table to assert its interests in the International Seabed Authority (where the United States is guaranteed permanent membership), the Continental Shelf Convention, and the International Tribunal for the Law of the Sea. Many opponents of the United States joining UNCLOS assert that “customary international law is sufficient,” but they dismiss the viability of customary international law in other contexts. Which is it?

To be sure, joining UNCLOS will not solve the climate crisis, negate China’s excessive maritime claims, nor magically restore U.S. credibility on the world stage. But do the advantages of joining UNCLOS outweigh any disadvantages? Is U.S. credibility enhanced by joining UNCLOS? Does joining UNCLOS help our freedom of navigation efforts in the South China Sea? Assist our efforts to address climate change? These are the questions that American leaders need to be asking.

Recently, several senators provided a legislative lifeline to reinvigorate the UNCLOS debate. Senators Mazie Hirono (D-HI), Lisa Murkowski (R-AK), and Tim Kaine (D-VA) introduced a bipartisan resolution calling on the Senate to ratify UNCLOS, complete with a helpful synopsis why it is time for Senate ratification. As the United States withdraws from Afghanistan and shifts away from the post-9/11 terrorism-focused strategy, these “three C’s” – China, climate change, and credibility – should reinvigorate a discussion on the Law of the Sea Convention and propel ratification now.

IMAGE: Filipinos take part in an anti-China protest outside the Chinese Embassy on July 12, 2019 in Makati, Metro Manila, Philippines. Protests marked the third anniversary of the Hague’s Permanent Court of Arbitration decision on the West Philippine Sea, which in 2016 ruled in favor of the Philippines and rejected China’s claims on the disputed waters. (Photo by Ezra Acayan/Getty Images)