The Other China Flash Point |
When imagining how the U.S.-China relationship might devolve into war, experts often cite Taiwan as the most obvious flashpoint. In recent years, after all, China has escalated its campaign of coercion against the island democracy, lobbing missiles over it, staging a blockade during live-fire military exercises, and threatening catastrophic punishments against third countries that expand ties with Taipei. Although the United States does not have a defense treaty with Taiwan, Beijing’s aggression against the island—paired with Chinese President Xi Jinping’s reported desire to be capable of invading by 2027—has prompted the U.S. military and policy community to accelerate steps that would strengthen cross-strait deterrence.
But if conflict does break out in the Western Pacific, it is more likely to erupt southwest of Taiwan, in the South China Sea, where numerous countries jostle over competing maritime claims and divergent visions of sovereignty, regional order, and international law. Beijing claims about 90 percent of the South China Sea, including waters off the coasts of Brunei, Indonesia, Malaysia, the Philippines, and Vietnam. Those five countries’ maritime claims—and Taiwan’s—also conflict with one another, but China’s claims and actions have been far more aggressive, including deployments of hundreds of ships, advanced missile systems, and combat aircraft to the coral reefs, rocks, and cays it occupies.
Tensions are highest between China and the Philippines, with Manila frequently calling public attention to Chinese harassment of Philippine ships operating lawfully within the Philippines’ exclusive economic zone. But violence also erupts periodically between China and other claimants. Since 2015, Chinese coast guard, militia, and civilian maritime personnel have killed or injured dozens of Vietnamese fishermen in the South China Sea. And in the 2010s, the Indonesian government routinely destroyed trespassing vessels from China and other countries. U.S. ships and aircraft, meanwhile, operate throughout the South China Sea, challenging Beijing’s expansive claims, affirming freedom of navigation and overflight, and helping Southeast Asian claimants withstand Chinese harassment.
No one wants to fight a war over an obscure set of rocks in the South China Sea. There will never be a U.S. president who is eager to convince the American people that defending freedom of navigation in Asia merits a great-power conflict. China would prefer to reserve its military capabilities for a potential scenario in Taiwan. Even in Manila or Hanoi, where upholding maritime sovereignty is a winning political issue, there is a strong preference for maintaining warm economic ties with China. Nonetheless, the risk that an accident in the South China Sea could rapidly escalate to a full-blown crisis remains substantial.
Washington has a legally binding alliance commitment to the Philippines. The U.S.-Philippine Mutual Defense Treaty of 1951 does not mention the South China Sea, referring instead to “the Pacific Area.” But since 2019, the United States has explicitly included the South China Sea as part of that geography, formally guaranteeing the Philippines’ security there. The White House, Department of State, and Department of Defense have repeatedly confirmed that an armed attack against Philippine armed forces, public vessels, or aircraft in the South China Sea would invoke U.S. mutual defense obligations. In a rare point of continuity, both Trump administrations and the Biden administration have used nearly identical language to underscore this commitment. As a result, if China kills a Philippine service member, even inadvertently, in the South China Sea, the United States could easily become a party to the conflict.
The United States, of course, could choose to abandon the alliance instead. It might judge that defending U.S. interests in the South China Sea is simply not worth the risk. Undoubtedly, the importance of these waters would seem to pale in comparison to Taiwan, a densely populated democracy and technological hub. But since 2019, Washington has been remarkably consistent in supporting Manila when it comes under pressure in the South China Sea, often offering even more assistance than the Philippines had requested. For Washington, standing up for Manila in the South China Sea is important in its own right. But it is also necessary for a successful defense of Taiwan. Only 53 nautical miles separate the Philippines from Taiwan at their closest point. In a cross-strait conflict, U.S. officials would depend on Philippine cooperation—and the United States can only retain Philippine support on Taiwan if they deliver for Manila in the South China Sea. If Washington blinks in the South China Sea, in other words, its ability to deter China in the Taiwan Strait could be fatally undermined.
Of the United States’s36 treaty allies, the only country that has taken casualties from China since the Korean War is the Philippines. In 2023, Beijing launched a fierce campaign against Philippine ships in the South China Sea, setting in motion a conflict that brought the United States and China to the brink of military confrontation. Chinese coast guard vessels rammed and fired water cannons at civilian Philippine ships seeking to resupply the Philippines’ outpost at Second Thomas Shoal, a feature that falls within the........