Policy Backgrounders

Potential Conflict in the South China Sea

November 09, 2023

As President Biden and Chinese President Xi Jinping prepare to meet in San Francisco next week on the sidelines of the Asia Pacific Economic Cooperation summit, tensions are mounting in the South China Sea. Merchant ships transiting the South China Sea carry approximately $3.4 trillion in commerce each year. Seven governments (China, Taiwan, Brunei, Indonesia, Malaysia, the Philippines, and Vietnam) assert sovereignty over portions of the South China Sea, with many claims overlapping. Of the competing claims, the one with the highest potential for military conflict concerns Chinese activity in the area the Philippines claims in the West Philippine Sea as an Exclusive Economic Zone (EEZ) under the UN Convention on the Law of the Sea (UNCLOS).

• The risk of miscalculation leading to direct conflict has grown significantly as both China and the Philippines have taken increasing measures to defend their claims. On October 22, tensions mounted leading to a collision between a China Coast Guard vessel and the Philippine Coast Guard vessel BRP Cabra and a civilian vessel chartered by the Philippines, which the Philippines termed a “blatant violation of international law” as the shoal is within the Philippines’ EEZ. China termed the incident a “slight collision” after “multiple warnings” and the boat “deliberately passed through law enforcement in an unprofessional and dangerous manner.” The Philippines called the collision “provocative” and warned of “disastrous results” if China continued to attempt to block resupply missions.
• The US and the Philippines have a Mutual Defense Treaty, ratified in 1952 and upgraded in May 2023 with new Bilateral Defense Guidelines specifically stating that an “armed attack . . . anywhere in the South China Sea” would invoke the Mutual Defense Treaty, raising the prospect of direct US involvement in any conflict.
• Regional powers and US allies Japan and Australia have recently upgraded their ties with the Philippines, including defense ties.