The unintended consequences of US deep engagement in the South China Sea

Deep engagement—the claim that power projection is the optimal policy to deter adversaries and maintain global security—is a commonly asserted proposition for US grand strategy. This article puts forward a theoretical corrective by carrying out a controlled comparison of recent conflicts in the South China Sea to test the logic of deep engagement at face value. Contrary to its claim, there is considerable evidence that deep engagement is neither necessary nor sufficient for deterring China’s coercive behaviour in the maritime dispute. A more salient exogenous factor for restraining China is whether the Association of Southeast Asian Nations (ASEAN) adopts a common threat perception of China’s unilateral provocations. When high levels of regional unity are observed, ASEAN’s collective response pushes back against China’s bellicose behaviour. Continued calls for US deep engagement in the South China Sea and regional security would thus need to be placed in the broader context of Southeast Asia’s security preferences.