The current conflict over the Prek Sah Rep (Stung Medo) area, a crucial irrigation site on the Koh Kong peninsula, is not a sudden eruption. The dispute stretches back decades, rooted in competing claims to the Tonle Sap River basin – the Mekong’s largest tributary – and intertwined with issues of sovereignty, resource control, and historical narratives. Treaties dating back to the French colonial era, notably the 1907 Treaty of Versailles and subsequent bilateral agreements, established the foundations for these competing claims. The 1960s saw heightened tensions with the construction of the Stung Tren dam by Cambodia, exacerbating the competition for water resources. The current confrontation, however, is fueled by the escalating development of hydropower projects upstream, primarily by China, which dramatically alters water flows impacting the Mekong’s delta, and by extension, Thailand’s strategic considerations. The Association of Southeast Asian Nations (ASEAN), while intended to promote peace and stability, has consistently struggled to effectively mediate these disputes due to a principle of non-interference in internal affairs, limiting its capacity to apply pressure or enforce resolutions. “ASEAN’s approach, characterized by dialogue and consensus, has repeatedly proven insufficient to address fundamental disagreements,” notes Dr. Amelia Tan, Senior Fellow at the ISEAS – Yusof Ishak Institute, “The inherent reluctance to confront powerful states like China has become a significant weakness in the organization’s ability to maintain regional security.” Data from the Mekong River Commission (MRC) confirms a concerning decline in the flow of the Mekong River, attributable primarily to upstream water extraction, compounding anxieties about water security for riparian nations.
Key Stakeholders and Motivations
Several actors shape the dynamics surrounding the Mekong. Cambodia, facing economic development pressures and seeking to assert its sovereignty, is prioritizing the development of hydropower projects to bolster its economy. China’s ambitious Belt and Road Initiative further complicates matters, increasing its influence over the Mekong’s flow and generating suspicions amongst its neighbors. Thailand, with significant agricultural interests reliant on the Mekong’s irrigation, is determined to secure its access to the river’s resources. Furthermore, the growing concern over online scam operations originating from Cambodia, targeting vulnerable populations globally, provides Bangkok with a valuable justification for asserting control and advocating for international cooperation. Thailand’s Minister of Foreign Affairs’ planned visit to Geneva, and his focus on combating online fraud, highlight this dual strategy – addressing the border conflict while leveraging international engagement on a broader security issue. “Thailand is caught between a rock and a hard place,” explains Dr. David Cohen, a specialist in Southeast Asian security at the International Crisis Group. “It must balance its economic interests with the need to maintain regional stability, while simultaneously managing its relationship with a powerful and increasingly assertive China.”
Recent Developments and Shifting Strategic Priorities
Over the last six months, the situation has intensified significantly. Satellite imagery has consistently shown increased Thai naval activity in the contested waters, raising the risk of confrontation. Cambodia has responded with its own naval deployments and increasingly assertive rhetoric. The January 2026 report by the International Crisis Group highlighted a concerning escalation in the deployment of military personnel along the border. Furthermore, Thailand has actively sought international support, notably through its participation in the High-Level Segment of the UN Human Rights Council, bringing attention to the human rights implications of the border conflict, particularly the issue of online scams and their impact on vulnerable populations. This shift is strategically important; using human rights concerns as a diplomatic tool allows Thailand to engage with global powers and exert pressure on Cambodia while subtly challenging its government’s legitimacy. Data released by INTERPOL suggests a dramatic increase in online scam-related crimes originating from Cambodia, with Thai victims representing a significant portion of the losses. This underscores the compelling link between the border dispute and Thailand’s broader security agenda.
Future Outlook and Potential Scenarios
Short-term, the next six months are likely to see continued tensions along the border, punctuated by sporadic clashes and heightened diplomatic activity. The outcome of the Minister’s upcoming meetings in Paris and Geneva will be crucial in shaping the next phase of negotiations. Long-term, the situation will depend heavily on China’s continued upstream water management practices and Cambodia’s economic development strategy. A scenario involving a protracted military standoff remains a significant risk. Alternatively, a negotiated settlement, potentially facilitated by ASEAN mediation, could be achievable if both sides are willing to compromise. However, the underlying dynamics – the competition for resources, the geopolitical influence of China, and Thailand’s desire to maintain regional leadership – suggest a complex and potentially volatile situation for the next 5-10 years. Ultimately, Thailand’s ability to successfully navigate this crisis will be a critical test of its commitment to regional stability and its capacity to adapt to a rapidly changing geopolitical landscape.
The increasingly complex dynamics of the Mekong represent more than just a border dispute; it is a microcosm of larger geopolitical shifts within Southeast Asia. The question for policymakers remains: can Thailand – and by extension, ASEAN – effectively manage this challenge, or will the Mekong become a flashpoint, further destabilizing a region already grappling with numerous security and economic uncertainties?