The second Trump administration seems likely to continue the policies of its predecessor in the South China Sea. This will be in marked contrast to radical changes in U.S. policy in Europe and the Middle East, and deep anxiety about U.S. intentions in Northeast Asia. President Donald Trump has no public position on the South China Sea; in his first four years in office, he never discussed the matter publicly and it did not appear in the readouts of phone calls or meetings with Southeast Asian counterparts. The first Trump administration did undertake important policy shifts in the South China Sea, including the regularization of Freedom of Navigation Operations, public clarification of the application of the U.S.-Philippines Mutual Defense Treaty, and a 2020 Position Paper on the South China Sea, but these were spearheaded by senior officials in the Departments of Defense and State, not the White House.
This pattern is repeating in the second Trump administration. Secretary of State Marco Rubio and Secretary of Defense Pete Hegseth made sure their first contacts in Southeast Asia were with their Philippine counterparts. Rubio issued a waiver exempting about $350 million in foreign military financing for the Philippines from the freeze on overseas assistance. And when a Chinese military helicopter engaged in an unsafe intercept of a Philippine aircraft near Scarborough Shoal in February, the State Department reiterated that the Mutual Defense Treaty applies to any attack on “the armed forces, public vessels, or aircraft of the Philippines – including its coast guard (a Biden-era addition)” which both reassures Manila and helps deter Beijing. Hegseth then made the Philippines his first stop in Asia while in office. During meetings with Secretary of National Defense Gilberto Teodoro and President Ferdinand Marcos, Jr., Hegseth reiterated the U.S. commitment to enhancing deterrence vis-à-vis China and supporting the modernization of the Armed Forces of the Philippines.
The administration is likely to iterate on the strategy pursued by its predecessor and which was already evident during the first Trump term. This involves working hand in glove with the Philippines to deter Chinese aggression, push back on its gray zone coercion, and shape the geopolitical environment in the hopes of convincing China to eventually seek compromise. The reason for sticking with this strategy is simple: it is already working.
Recent Southeast Asian Successes
China is in no greater control of the South China Sea today than it was four years ago. In some areas, it has even lost ground to other claimants. This is because Southeast Asian states have discovered that they can, in fact, stand up to gray zone pressure so long as China remains unwilling to escalate to lethal force. And thanks in part to U.S. deterrence, that remains a line over which Beijing has refused to step.
Oil and gas exploration is an important example of Southeast Asia’s recent successes. In the latter half of 2021, Indonesia conducted exploratory drilling in the Tuna block, an oil and gas concession at the southern edges of the South China Sea. Beijing responded by deploying China Coast Guard (CCG) vessels to try and block the operation, the first time Chinese forces had physically harassed Indonesian oil and gas activities. Jakarta deployed its own law enforcement and navy ships to protect the drilling. The standoff lasted three months but Indonesia completed the operation as scheduled.
At about this time, Vietnam also began to push back more forcefully on the oil and gas front. It greenlit new drilling in the Nam Con Son field near Vanguard Bank, which provides a substantial amount of electricity for Ho Chi Minh City. As with Indonesia, the CCG deployed to harass the operations. Vietnam sent its own vessels to protect the drilling, which went ahead as scheduled. The continued operations at Nam Con Son and the Tuna block are why the CCG now maintains an almost daily presence at Vanguard Bank. But to-date, China has nothing to show for that effort. Last October, Indonesia began exploratory drilling at another nearby field with the same results. The CCG deployed, Indonesian ships sailed out to protect the operation, and the drilling went ahead.
Malaysia has by far the most successful offshore oil and gas industry in the South China Sea. CCG vessels have been patrolling Luconia Shoals to harass these operations since late 2013. That had some successes, for instance in disrupting drilling operations on the Malaysian extended continental shelf in 2020. But Malaysia’s state-owned Petronas has since embarked on an ambitious expansion of its offshore operations, most importantly at a gas field called Kasawari. Along with daily CCG patrols, a diplomatic letter leaked in September 2024 revealed that China has been putting considerable political pressure on Kuala Lumpur to halt this work. Malaysia nevertheless drilled a record 25 offshore wells in 2023 and another 15 in 2024.
Recent China-Philippines tensions show Beijing’s strategy failing in more spectacular, and dangerous, fashion. After years of accommodating Chinese demands, the Philippine Navy and Coast Guard are patrolling disputed waters more visibly, and the government is speaking up publicly when faced with Chinese harassment, supported by a renaissance in the U.S.-Philippines alliance. The administration of President Ferdinand “Bongbong” Marcos, Jr., which took office in July 2022, has reestablished coastguard patrols near Scarborough Shoal for the first time since 2012. The Philippines has also enhanced its military posture in the Spratlys, especially around Thitu Island. This has resulted in pushback from the CCG and Chinese militia, including dangerous forms of gray zone violence, but the Philippines has been undeterred.
From February 2023 to August 2024, the CCG and militia attempted to blockade Second Thomas Shoal, where the Philippines maintains a tenuous military presence aboard the grounded BRP Sierra Madre. The Philippines had determined that the ship was in desperate need of repair and began bringing in construction supplies, giving an excuse for the blockade. The number of Chinese ships around the shoal approached 50 by December 2023 and their tactics grew progressively more violent. CCG and militia vessels have a track record of navigating unsafely around foreign vessels, intentionally creating risks of collision. At Second Thomas, that escalated to intentional shouldering and ramming, at times by several Chinese vessels at once, and it targeted both Philippine government and civilian ships. The CCG also became more adept at using its favorite weapon, deck-mounted high pressure water cannons. Positioning two CCG ships to hit a Philippine vessel from both sides became a typical tactic, often shattering windows, injuring crew, and drowning the targeted vessel’s engines. The CCG and militia also made occasional use of dazzlers, or military-grade lasers, and acoustic devices to blind and disorient Philippine sailors. Despite the pressure, every monthly Philippine resupply mission made it through the blockade.
In June 2024, this experimentation with gray zone tactics came to a head. The Philippine Navy deployed rigid hulled inflatable boats (RHIBs) to maneuver around China’s vessels and deliver supplies to the Sierra Madre. The CCG dispatched its own RHIBs to intentionally ram the Philippine vessels and then threatened the Filipinos with knives and other weapons. During this attack, a Filipino sailor was pinned between two boats and lost his thumb. He survived, but China seemed to realize how close its supposedly “non-lethal” gray zone tactics had come to triggering potential U.S. intervention under its Mutual Defense Treaty. Soon after, China and the Philippines agreed to a provisional arrangement to deescalate tensions around the shoal. Manila agreed because it had successfully repaired the Sierra Madre. Beijing accomplished nothing.
Its behavior at Second Thomas also worsened the strategic environment for China. It accelerated the once-in-a-generation modernization of the U.S.-Philippines alliance, which has been underway since late 2021. This modernization is crucial in deterring Chinese aggression and keeping the disputes in the gray zone where, while dangerous, the dynamics appear to favor Southeast Asian claimants. The standoff around Second Thomas also facilitated greater Philippine integration into an emerging regional security architecture. Manila and Tokyo concluded a Reciprocal Access Agreement in July 2023 to allow joint training and exercises. Similar agreements are nearing completion with New Zealand, Canada, and France. A new trilateral architecture among the United States, Japan, and the Philippines has emerged alongside a quadrilateral arrangement, sometimes dubbed the “Squad,” with Australia.
And at the diplomatic level, Manila has leveraged the violence it faced to persuade 28 countries and counting to publicly demand Beijing comply with the 2016 arbitral award that threw out most of China’s maritime claims. This will be key in the next step for U.S. and Philippine strategy: shaping the geopolitical environment to convince Beijing, likely under a future leader, to seek compromise.
Future Lawfare Options
After nearly a decade, China still refuses to comply with the landmark 2016 South China Sea arbitral award, and the Philippines has little to show for its victory. That does not, however, make the ruling a dead letter. It remains Manila’s best tool to maneuver Beijing into a compromise. As a result of the Marcos administration’s efforts, the Philippines has more than tripled the number of governments publicly calling on Beijing to comply with the ruling—from just 8 when Marcos took power to 28 today.
Since last year, Philippine officials have been exploring the possibility of a second arbitration. At least two options are under consideration: a second arbitration under Annex VII of the UN Convention on the Law of the Sea, which would likely focus on environmental damage caused by China; or a broader case, in a venue that has not been clearly articulated. In addition, during the annual session of the United Nations General Assembly in September 2024, the Philippines gathered senior officials from more than 20 countries “to give a signal to China” that Manila is not isolated on the South China Sea disputes. Such legal and diplomatic options are mutually reinforcing. In fact, making greater use of the United Nations is vital for the Philippines to expand its options for arbitration.
The United Nations cannot compel China to comply with the 2016 arbitral award or to cease its illegal behavior in the South China Sea. With Beijing’s permanent seat on the Security Council, the United Nations wouldn’t even be able to pass a binding resolution to that effect. But the General Assembly would be able to pass nonbinding resolutions and, most importantly, forward the matter to the International Court of Justice (ICJ) for an advisory opinion. This is the path that Mauritius successfully took over the last decade regarding the Chagos Archipelago. It filed multiple UN resolutions and cases in different venues against the United Kingdom, eventually cajoling London into a negotiation. If Manila takes that same path, it is almost certain to have the votes it needs in the General Assembly.
Based on public stances, the Philippines could count on at least 44 votes: those of the 28 countries that have already called for China to comply with the 2016 ruling, plus most of the 20 others who have issued positive statements about the arbitration. China, by contrast, has public support from only seven member states, two of which (Montenegro and Vanuatu) would be likely to abstain. That leaves 139 member states with no public stance on the South China Sea. Modeling based on historical UN voting behavior suggests that the Philippines could expect to carry a South China Sea-related vote by at least 62 to 44, with up to 87 abstentions.
Losing a General Assembly vote would not compel Beijing to suddenly abide by the South China Sea arbitration or to enter fair negotiations with Manila. But repeated losses in different international bodies would raise the costs of noncompliance and make a face-saving compromise progressively more attractive. Manila could start by filing a UN resolution demanding compliance with the 2016 arbitration, which it would likely win. It could file another seeking an ICJ advisory opinion on any number of issues, such as whether China’s behavior violates international treaties including the UN Charter and the International Regulations for Preventing Collisions at Sea. It would probably win that too, which would lead to yet another vote demanding China’s compliance. Manila’s margin of victory could be expected to grow with each vote, as happened for Mauritius. This could all move in parallel with a second arbitration filed under UNCLOS.
With support from the United States, the Philippines and its neighbors have since 2021 successfully resisted gray zone coercion and deterred Chinese military aggression. That will not solve the disputes, but it buys time for a long-term diplomatic effort to shape the strategic environment, damaging Chinese credibility and incentivizing an eventual compromise. Such a strategy will take years, probably until Xi Jinping leaves power. There are no quick solutions to the South China Sea, but if they can persevere, U.S. allies and partners are in a better position than China to achieve their aims.