Stretching over 3.5 million square kilometers from the straits of Taiwan and Malacca to the busy ports of Vietnam and the Philippines, the South China Sea is far more than a body of water. It is a geopolitical fulcrum, an economic artery, and a growing flashpoint for great-power competition. For the nations that border it—Brunei, China, Indonesia, Malaysia, the Philippines, Taiwan, and Vietnam—the sea represents national livelihood, historical heritage, and strategic depth. For the rest of the world, particularly the United States and its allies, it is a test case for the future of the international rules-based order. To understand the stakes, one must first look at the sheer volume of commerce that transits these waters. Approximately one-third of global shipping passes through the South China Sea each year, carrying over $3 trillion in trade. From oil and liquefied natural gas from the Middle East to manufactured goods from China and electronics from Southeast Asia, the sea is the world’s busiest maritime corridor.
The Biden administration has reaffirmed the U.S. commitment to its treaty allies—the Philippines, Japan, South Korea, and Australia—while deepening security ties with Vietnam and Malaysia. The pact (Australia, U.K., U.S.) and intensified joint naval drills are signals that Washington will not cede strategic control of the sea lanes.
The most contentious element is China’s claim, known as the This sweeping demarcation, originally drawn in 1947, encompasses nearly 90% of the South China Sea, including waters within 200 nautical miles of the coasts of Vietnam and the Philippines. Critics argue that the line has no basis in international law, as it claims entire archipelagos and vast expanses of high seas, ignoring the exclusive economic zones (EEZs) of other coastal states. south china sea
In a landmark 2016 ruling, the Permanent Court of Arbitration in The Hague rejected China’s claims, stating that there was “no legal basis” for China to claim historic rights to resources within the nine-dash line. The court also ruled that certain features claimed by China, such as Mischief Reef, are rocks that do not generate a full EEZ. China has refused to recognize the ruling, insisting on bilateral negotiations rather than multilateral or international legal mechanisms. Since the early 2010s, China has transformed its presence in the region through a massive land-reclamation and construction program. Previously uninhabitable reefs and shoals have been converted into artificial islands with runways long enough for fighter jets, radar installations, anti-aircraft missile batteries, and deep-water harbors.
Crucially, the sea is also a vital fishing ground, providing protein and income for tens of millions of people across the region. For nations like Vietnam and the Philippines, access to these waters is not just an economic issue; it is a matter of food security and rural employment. At the heart of the tension lies a complex web of overlapping territorial claims. The primary claimants—China, Vietnam, the Philippines, Malaysia, Brunei, and Taiwan—assert rights based on historical maps, proximity, or the United Nations Convention on the Law of the Sea (UNCLOS). Stretching over 3
By J. Harper, Strategic Affairs Correspondent
In the coming decade, the most likely outcome is neither a grand bargain nor a war, but a persistent, low-boil confrontation. The ships will continue to sail, the islands will continue to be fortified, and the diplomats will continue to talk. The only certainty is that the South China Sea will remain the world’s most dangerous and important stretch of water. For the rest of the world, particularly the
Key locations like now function as military outposts. While China describes these facilities as civilian and defensive in nature—useful for navigation safety and disaster response—neighboring nations and the Pentagon see them as offensive forward operating bases. They allow the People’s Liberation Army Navy (PLAN) to project power deep into the sea, challenging the decades-old U.S.-dominated naval order. The Role of External Powers: The United States and Allies No discussion of the South China Sea is complete without addressing the role of the United States. As the region’s preeminent external security partner, Washington has maintained a policy of “freedom of navigation” (FONOPs). Regularly, U.S. Navy warships sail within 12 nautical miles of Chinese-claimed features, a direct challenge to what Washington considers excessive maritime claims.