The Centrality of ASEAN Tested by Thailand-Cambodia Conflict

Recent armed clashes along the border between the two member countries of the Southeast Asian group call into question the region’s core principle

By Emanuele Ballestracci

Since 2008, with the codification of the principle of “ASEAN Centrality,” its ten member states have pursued the ambition of making the organization the cornerstone of the Indo-Pacific regional architecture and the main channel of engagement with external partners. This perspective has immediately been tested by internal crises—such as the civil war in Myanmar—and by the inability to adopt common diplomatic positions, particularly regarding maritime disputes with China. In this context, the recent conflict between Thailand and Cambodia has only highlighted the difficulties in implementing this principle.

With the entry into force of the ASEAN Charter—the organization’s founding document—the principle of “Centrality” was formally enshrined, a concept that had already emerged in the 1990s with the establishment of the ASEAN Regional Forum and the ASEAN+3 format. The Charter came in a climate of renewed optimism, following the completion of the enlargement that brought the organization to include, beyond the five founding members (Indonesia, Malaysia, Singapore, Thailand, and the Philippines), also Brunei, Vietnam, Laos, Myanmar, and Cambodia. This was a step forward intended to strengthen ASEAN’s relevance on the international and, above all, regional stage. However, the effective application of “Centrality” appeared from the outset to be challenging due to several factors: unresolved territorial disputes; an institutional architecture not designed to fulfill this role; increasing international instability; and the different alliance systems of the members—despite the traditional non-alignment policy that unites them.

Although ASEAN Centrality has been recognized by the United States, the European Union, and numerous other small and medium powers, and implemented through platforms such as the East Asia Summit and the ASEAN Regional Forum, the inability to develop common positions on crucial dossiers—from the crisis in Myanmar to the disputes in the South China Sea—has made it clear that full implementation remains complicated. Notable examples include the failure to reach consensus in 2012 on a joint communiqué that would have articulated a common position on China’s growing assertiveness in the South China Sea, and the inability to jointly conduct negotiations for the Code of Conduct (CoC) aimed at regulating activities in the area. In the first case, Cambodia and Laos blocked the initiative under pressure from Beijing—their main economic and security partner—while the stagnation of the CoC, often attributed to the lack of willingness of some members, is pushing the Philippines to strengthen defense cooperation with the United States. It emerges that the lack of unity among ASEAN countries is the main obstacle to the very principle of “Centrality.”

These critical issues had already been recognized within the organization, to the point that in January 2025 a workshop was launched to explore possible reforms of norms and practices to allow ASEAN to reposition itself at the center of regional security architecture. However, the conflict between Thailand and Cambodia that erupted in July, causing 36 deaths and over 300,000 displaced persons, has further weakened these efforts. Latent territorial disputes, strong nationalism, and the need for both governments to redirect internal discontent outward have at least temporarily interrupted one of ASEAN’s achievements: the absence of armed conflicts between member states since its founding in 1967. 

The inability to reach an agreement on resolving the dispute raises further questions, as the escalation has made any concession even more costly for both parties. Moreover, should tensions persist, a plausible scenario includes the reopening of U.S. military bases in Thailand and a further strengthening of Sino-Cambodian defense cooperation.

The principle of ASEAN Centrality, constantly tested by internal and international challenges, currently needs to be reaffirmed and promoted in a cohesive manner.