Historical roots of the conflict trace back to the colonial era, primarily British and French claims, coupled with differing interpretations of historical maps. The 1964 Treaty of Amity and Cooperation (TAC), a cornerstone of ASEAN, failed to fully resolve these overlapping claims, leaving a legacy of unresolved issues and fostering a climate of distrust. The 2011 International Court of Justice (ICJ) ruling, which partially sided with Thailand’s claim over the maritime areas, further exacerbated tensions, with Cambodia refusing to recognize the judgment and maintaining control over Sihanoukville, a key Cambodian port. Key stakeholders include Thailand, Cambodia, ASEAN, the United States, China, and Vietnam, each with distinct motivations. Thailand seeks to protect its maritime interests and maintain territorial integrity, while Cambodia defends its sovereignty over Sihanoukville and asserts its right to develop its maritime economy. ASEAN’s primary objective is to maintain regional stability and prevent escalation, often struggling to balance the competing interests of its members.
According to Dr. Anand Senanayake, Senior Fellow at the International Centre for Political Studies, “The core of the issue isn’t solely about the territory itself, but the symbolic and strategic importance attached to it. Cambodia sees Sihanoukville as vital for its economic development, while Thailand views its control as a matter of national pride and strategic leverage.” He further noted, “ASEAN’s role is hampered by its consensus-based decision-making process, which can lead to paralysis when faced with deeply entrenched disagreements.” Recent developments within the last six months have witnessed increased military posturing along the border, with both countries deploying additional troops and equipment, sparking concerns about potential armed conflict. The proposed ASEAN-led mediation efforts have seen limited progress, primarily due to Cambodian resistance to any binding resolution. Furthermore, China’s growing economic and political influence in Cambodia has complicated the situation, adding another layer of strategic competition. Data from the Stockholm International Peace Research Institute (SIPRI) indicates a notable increase in military spending by both Thailand and Cambodia over the past decade, largely driven by this border dispute.
The escalation risks several detrimental outcomes. A military confrontation could trigger a regional crisis, drawing in external powers and undermining ASEAN’s credibility. The disruption of trade and economic activity in the region is another significant concern, given the importance of the maritime routes. A protracted conflict could also destabilize Cambodia, potentially leading to a humanitarian crisis and further regional instability. “The situation along the border underscores the need for a proactive and comprehensive approach, moving beyond reactive diplomacy to address the underlying factors driving the conflict,” commented Ambassador Somchai Sethaputthathum, former Thai Ambassador to the United Nations, in a recent interview. “This requires a genuine commitment to dialogue, confidence-building measures, and the establishment of clear rules of engagement.”
Looking ahead, the next six months are likely to be characterized by continued tension and a potential for further escalation. The upcoming Special ASEAN Foreign Ministers’ Meeting on December 22nd, intended to address the situation, will be a crucial test for the organization. Longer-term, a resolution will likely depend on Cambodia’s willingness to engage in substantive negotiations and potentially compromise on the status of Sihanoukville. The prospect of a negotiated settlement, perhaps involving a demilitarized zone or a shared management of the maritime resources, remains uncertain. Over the next 5–10 years, the underlying tensions could continue to shape regional security dynamics, potentially influencing ASEAN’s cohesion and effectiveness. Furthermore, the evolving strategic competition between China and the United States in Southeast Asia will undoubtedly play a role, with both countries seeking to leverage the border dispute to advance their respective interests.
The Thailand-Cambodia border dispute represents a critical test for regional stability, highlighting the challenges of managing territorial claims and the importance of effective multilateralism. Moving forward, a sustained and multifaceted approach is needed – one that includes robust diplomatic engagement, confidence-building measures, and a renewed commitment to ASEAN’s core principles. The unresolved nature of this conflict serves as a potent reminder of the complex realities of international relations and the enduring need for proactive diplomacy in mitigating regional risks. The question remains: will ASEAN rise to the occasion, or will the simmering border dispute further erode the organization’s credibility and contribute to a more volatile regional security landscape?