The South China Sea could become a major flashpoint in 2025

In early 2024 Taiwan looked like the most dangerous flashpoint in Asia. China, which claims the self-governing island as its own, was frustrated by Lai Ching-te’s victory in a presidential election there in January. It had branded him a “dangerous separatist” who could provoke war. Soon after his inauguration in May, Chinese forces staged two days of naval and air drills around the island, putting military commanders on edge in America, bound as it is, by law, to help Taiwan defend itself.

In 2025 the focus of concern may shift southward. In the South China Sea, long-running friction over disputed rocks and reefs has escalated into dramatic clashes at sea. They have mostly occurred between Chinese and Philippine coastguard vessels. But with neither side willing to back down, such encounters could quickly escalate into a naval confrontation that might suck in America, a treaty ally of the Philippines.

One place to watch is Sabina Shoal. The outcrop in the Spratly Islands lies 150km west of the Philippine province of Palawan, but is also claimed by China, Vietnam and Taiwan. No claimant has a long-term presence. But the Philippines stationed its largest coastguard vessel at the shoal for five months in 2024, alleging that China was about to start building there. China sent its own ships in response, one of which rammed the Philippine vessel. The Philippines withdrew its ship in September but has promised continuous patrols there.

Second Thomas Shoal, also in the Spratlys, is another possible flashpoint. The Philippines has controlled it since 1999, when it grounded an old ship there. In 2023 it started trying to take in building materials to reinforce the hull. China responded with a blockade and by disarming a Philippine navy mission to break it in June. The two sides have since reached an agreement whereby China “inspects” all shipments—from a distance—to ensure no construction materials are brought in. How long this will last is unclear.

The outcrops involved may seem too small and remote to be worth risking a broader flare-up. Yet each side has cause to stand firm. The Philippines’ president, Ferdinand “Bongbong” Marcos, has pledged to do more than just protest against Chinese encroachment in waters claimed by his country. America is also determined to reinforce its treaty with the Philippines and to stop what it calls Chinese “salami-slicing”—small acts of aggression that make territorial gains. China sees the chance to show America’s allies that they cannot rely on it for help.

There are signs that other countries are becoming more assertive. Vietnam has been dredging and reclaiming land on features it occupies in the Spratlys. By June 2024 it had built up about half as much land as China did during construction of seven new military bases in the Spratlys in 2013-16. It also appears to be building a second airstrip. Even Malaysia (which is generally averse to confronting China) has expanded hydrocarbon exploration in disputed waters.

What happens will depend, in part, on how Donald Trump’s administration views the problem, and the relationship with China more broadly. Relations over the reefs could get rockier still. ■