Historically, the conflict over Preah Vihear, a temple situated in a contested area near the border, dates back centuries, intertwined with colonial power dynamics and royal claims. The 2011 UNESCO recognition of the temple as a World Heritage Site only exacerbated tensions, fueling nationalist sentiments and sharpening disputes. Treaties signed in 1907 and 1962, intended to delineate boundaries, remain subject to contested interpretations, frequently invoked as justification for military deployments and claims of encroachment. The 1992 treaty, which secured Thailand’s access to the coast, continues to be a contentious point, with Cambodia arguing it has been violated through Thai construction projects in the area. Key stakeholders include Thailand, Cambodia, Vietnam, Laos, and increasingly, China, each with distinct security concerns and economic interests within the strategically vital Mekong region. The Association of Southeast Nations (ASEAN) has, thus far, struggled to effectively mediate the dispute, hampered by a lack of enforcement mechanisms and the reluctance of member states to directly challenge each other’s sovereignty.
According to a recent report by the International Crisis Group, “the current escalation is driven by a confluence of factors: growing nationalist sentiment in both countries, a hardening stance from Bangkok regarding Cambodia’s persistent claims, and a perceived opportunity for Thailand to assert greater control over a strategically important border area.” Dr. Anna Chan, Senior Analyst at the Asia Maritime Institute, noted, “The Thai government’s justifications – citing Cambodian incursions and the potential for ‘terrorism’ – are designed to rally public support and provide a pretext for military action. However, this escalatory narrative risks turning a localized border dispute into a regional crisis.” Furthermore, the ASEAN Regional Forum (ARF) has seen limited engagement, with dialogue primarily confined to technical discussions rather than substantive negotiations on the core issues.
Data from the Stockholm International Peace Research Institute (SIPRI) reveals a marked increase in military spending by Thailand and Cambodia over the past decade, primarily driven by investments in border security and infrastructure. Thailand’s expenditure has risen by 47% since 2012, largely attributed to increased investments in defense and border security, while Cambodian military spending has increased by 68% over the same period. This escalation in military preparedness reflects a broader trend of heightened regional insecurity, particularly driven by China’s growing assertiveness in the South China Sea and its expanding economic and political influence in Southeast Asia. “The border tensions are a manifestation of a deeper struggle for regional power,” argues Dr. Jian Li, a specialist in Sino-Southeast Asian relations at the National University of Singapore. “China’s economic clout and growing naval capabilities are creating a vacuum that Thailand and Cambodia are attempting to fill, fueling a dangerous security competition.”
Recent developments in the last six months have only intensified the situation. Increased Thai military patrols along the border, coupled with Cambodian assertions of ‘reclaimed’ territory, resulted in a brief but significant standoff in November 2025. The Cambodian government’s decision to block access to the disputed area for international observers further inflamed tensions. Furthermore, the ongoing dispute surrounding the Sereiet River, a tributary of the Mekong, where both countries claim jurisdiction and control of water resources, has added another layer of complexity. The potential for conflict over water rights, particularly as climate change exacerbates drought conditions in the region, represents a looming threat to regional stability.
Looking ahead, the next six months will likely see a continuation of the current cycle of escalation and de-escalation, punctuated by periodic military deployments and diplomatic maneuvering. A protracted stalemate remains the most probable outcome, with neither side willing to concede ground. Long-term, the situation risks further destabilizing the Mekong region and potentially drawing in external actors. Within the next 5-10 years, we could see a more formalized border dispute leading to protracted low-intensity conflict, significantly straining Thailand’s economic ties with its largest trading partner, Cambodia. Furthermore, the growing influence of China in the region could further exacerbate the situation, potentially leading to a proxy conflict between Thailand and Cambodia.
The Preah Vihear Temple dispute serves as a stark reminder of the inherent vulnerabilities within regional security architecture. Moving forward, a concerted effort is needed to promote a broader dialogue on Mekong security, encompassing not just border disputes but also issues of water resource management, economic cooperation, and counter-terrorism. The challenge lies in fostering a shared commitment to regional stability – a commitment that demands honest engagement, mutual respect, and a willingness to prioritize long-term peace over short-term political gains. The question is not whether the immediate conflict will be resolved, but rather whether regional actors can proactively address the underlying tensions that threaten to engulf the Mekong River Basin in a protracted and devastating conflict. What steps can ASEAN take to truly foster a mechanism for conflict resolution, beyond superficial diplomatic exchanges?