Vietnam’s Participation in QUAD Plus: Strategic Motivations and Impacts on the Security Architecture of the South China Sea

Amid the shifting Indo-Pacific regional order under the influence of power competition between the United States and China, the Quadrilateral Security Dialogue (Quad) has emerged as a crucial mechanism in shaping regional security structures. Quad Plus, an expanded version of Quad, including Vietnam, South Korea, New Zealand and a number of other countries, has great significance for Vietnam’s foreign and security policy. The chapter employs a policy analysis approach and international relations theory to examine the strategic motivations behind Vietnam’s engagement in Quad Plus, including the need to improve maritime capacity, strengthen cooperation with major powers to deal with non-traditional security challenges, and strengthen diplomatic position in the region. The chapter concludes that cooperation with Quad Plus enables Vietnam to improve its defense and security capabilities, especially in the fields of technical assistance, maritime training, and intelligence sharing. This contributes to enhancing strategic deterrence against sovereignty violations in the South China Sea. In particular, Vietnam’s participation in Quad Plus has a profound impact on the security architecture of the South China Sea, as the group plays an increasingly pivotal role in upholding freedom of navigation and countering coercive actions. Furthermore, the study provides policy recommendations for optimizing Vietnam’s national interests in the context of evolving regional geopolitics.