Few security challenges are as vexing as the South China Sea. With multiple claimants and murky claims, the contours of the conflict can be difficult to grasp. In recent years, China has used ambiguity, asymmetry, and incrementalism to assert control over parts of the South China Sea. Meanwhile, the Obama administration attempted to draw red lines against “reclamation, construction, and militarization.” Yet, Beijing nevertheless reclaimed, constructed, and militarized all seven of the features it controls in the Spratly Islands.
Incoming Trump administration officials have indicated that they will adopt a more forceful approach to Chinese activities in the South China Sea. As the administration develops this new strategy, U.S. leaders must decide which Chinese actions they can deter at an acceptable level of risk. In so doing, they should evaluate eight potential South China Sea crisis scenarios:
- Reclamation at Scarborough Shoal: In 2012, China wrested control of Scarborough Shoal from the Philippines. In 2016, the Obama administration appeared to deter a Chinese effort to build a base atop the shoal. An airfield on Scarborough Shoal would give Beijing a geographically valuable base in the northeast South China Sea.
- Blockade of Second Thomas Shoal: In 2014, China harassed Philippine vessels attempting to resupply Philippine marines on a rundown vessel atop Second Thomas Shoal. U.S. assistance has helped to ensure that resupplies continue, but more Chinese pressure is likely and a clash could trigger the U.S. treaty commitment to the Philippines.
- Announcement of an Air Defense Identification Zone (ADIZ): In 2013, China announced an ADIZ that covered most of the East China Sea. One concerning aspect of the ADIZ was Beijing’s requirement that aircraft file flight plans, even if they were not planning to enter Chinese airspace. Many experts believe that Beijing will create a similar zone in the South China Sea once it has the ability to monitor the most remote portions of the region’s airspace.
- Declaration of straight baselines in the Spratly Islands: In 1996, China announced straight baselines around the Paracel Islands, connecting 28 low-water points on different features. Beijing’s claim to waters internal to the Paracel Island chain is invalid because China is a continental state and therefore cannot establish archipelagic straight baselines. Nevertheless, China could announce straight baselines in the Spratly Islands, despite the illegality of such an action.
- Further militarization of the Spratly Islands: In 2015, President Xi Jinping stated that China did not intend to militarize the Spratly Islands. Yet, China now has point defenses on all its artificial islands in the Spratlys and airfields with hardened shelters on three features. Deployment of fighter aircraft or mobile surface-to-air missiles is also possible.
- Exploration of oil and gas in disputed waters: In 2014, China moved an oil rig into waters within Vietnam’s claimed exclusive economic zone. A similar situation could occur again, perhaps in a location such as the disputed Reed Bank. These platforms can also extend China’s maritime surveillance capabilities, as is occurring in the East China Sea.
- Harassment of fishermen or oil and gas surveyors: In 2016, an arbitral tribunal concluded that Chinese interference with Filipino fishermen in parts of the South China Sea is illegal. Such harassment continues, however, and could widen to include challenges to oil and gas rigs operating in disputed waters.
- Contestation of military operations in international waters and airspace: China has frequently complained about and challenged U.S. ships and aircraft operating in what Beijing calls “close in” operations. Yet, ships and aircraft are free to operate in international waters and airspace, regardless of China’s desire to stop U.S. surveillance.
Any of these potential scenarios could require a rapid response by the U.S. government, but reacting after the fact is a recipe for deterrence failure. Therefore, one of the administration’s most urgent tasks should be to determine beforehand which of these actions it will attempt to deter. Some possible Chinese actions—such as harassment of fishermen—may be deterrable with limited risk, but may not be a high priority for U.S. forces that are already stretched thin. Other Chinese actions—such as further militarization of the Spratlys, where China has already built hardened fighter hangers and deployed anti-aircraft guns and other point defenses—have significant military implications, but would be very difficult to deter (to say nothing of rolling back) at an acceptable level of risk. Carefully calibrating risk and reward will be necessary if the administration is to develop a credible South China Sea deterrence strategy.
The United States needs a more robust, clear, and credible strategy in the South China Sea, but drawing unenforceable red lines risks creating a red carpet for Chinese coercion. As the new administration constructs its South China Sea approach, senior leaders must remember that the center of gravity in Asia is the alignment decisions of regional states. If the United States takes so much risk in the South China Sea that it scares away its allies and partners, Washington will lose its most important advantage in the region. After all, U.S. allies and partners fear not only abandonment by the United States, but also entrapment in an unwanted conflict.
