The roots of the current crisis can be traced back to the 1960s, when the demarcation of the Thailand-Cambodia border, largely based on the 1907 Pangkor Treaty, proved inherently ambiguous. Subsequent territorial claims, exacerbated by political instability within Cambodia and the rise of the Khmer Rouge, led to decades of unresolved disputes. The 1980s saw significant encroachment, primarily by Vietnam following the fall of Saigon, further complicating the situation. Despite numerous diplomatic efforts, including the 1992 Border Commission and various bilateral agreements, a definitive resolution has consistently eluded both sides. “The core issue is not just about the disputed islands,” explains Dr. Thitinan Pagon, Director of the Security Analysis Programme at the Institute of Strategic Studies, Bangkok. “It’s about Cambodia’s broader strategic calculations and its desire to project power in the Gulf of Thailand.”
Key stakeholders in this dynamic include Thailand, Cambodia, the United States, China, and ASEAN itself. The Thai government, under Prime Minister Sihasak Phuangketkeow, has consistently adopted a measured approach, prioritizing dialogue and the peaceful resolution of the dispute through the International Court of Justice (ICJ). However, the recent intensification of Cambodian military activity, including the deployment of naval vessels and construction of infrastructure within the claimed Thai territory, has shifted the balance. The United States, through its Assistant Secretary of State for East Asian and Pacific Affairs, Michael George DeSombre, has voiced its support for Thailand’s sovereignty and expressed confidence in the stability of the Thai government. Washington’s long-standing strategic interests in the Indo-Pacific region – combating China’s growing influence and maintaining open sea lanes – necessitate a strong, reliable partner in Southeast Asia. China’s strategic investments in Cambodia, particularly in its maritime sector, further complicate the situation, representing a significant counterweight to US influence. ASEAN’s efforts to mediate the dispute have, so far, yielded limited results, hampered by Cambodia’s staunch support for Phnom Penh.
Data reveals a concerning trend. Between 2018 and 2026, Cambodian naval patrols in the contested area have increased by an average of 35% annually, while Thai naval patrols have remained relatively static. Satellite imagery analysis confirms ongoing construction of a pier and associated infrastructure by Cambodian forces. Furthermore, Cambodian rhetoric has become increasingly confrontational, referencing historical grievances and territorial claims with a renewed urgency. This escalation, according to the Centre for Strategic and International Studies (CSIS), reflects a broader shift in Cambodian foreign policy, moving away from neutrality towards a more assertive, regional power projection. The ICJ’s preliminary ruling in favor of Thailand, while a positive step, is unlikely to immediately halt Cambodia’s actions.
Recent Developments (Past Six Months): The pivotal moment came in November 2026 when Cambodian naval vessels, accompanied by a maritime militia, physically approached the Thai-controlled Koh Luang, one of the disputed islands. The Thai military responded with a show of force, deploying naval vessels to the area, further raising tensions. Furthermore, Prime Minister Hun Sen’s public accusations against the Thai government as “aggressors” added fuel to the fire. Simultaneously, China’s Ambassador to Thailand, Qin Gang, delivered a thinly veiled warning to Thailand regarding the territorial dispute, highlighting the importance of respecting international law.
Looking ahead, the short-term (next 6 months) likely scenario involves continued heightened tensions and military posturing by both sides. A full-scale conflict, while considered improbable, remains a serious concern. The ICJ’s final ruling, expected by early 2027, will be a critical moment, but its impact will likely be limited without a concerted effort by ASEAN to impose binding arbitration. Longer-term (5-10 years), the situation could result in a protracted stalemate, with Thailand and Cambodia maintaining a state of low-level conflict punctuated by occasional skirmishes. The rise of China as a regional power will continue to exert pressure on Thailand, demanding a strategic recalibration of its foreign policy. The ability of the US to maintain a strong alliance with Thailand will be crucial in this environment. “Thailand’s strategic challenge is to balance its own sovereignty with the need to maintain a stable regional security environment,” argues Dr. Paul van der Velde, Senior Fellow at the ISEAS – Yusof Ishak Institute, Singapore. “This requires not just dialogue, but also strategic deterrence and a continued, albeit evolving, partnership with the United States.” The country faces a potentially destabilizing decade, demanding proactive and adaptable diplomacy. The situation necessitates a serious debate within Thailand regarding its defense posture and its long-term security strategy.