Thailand has formally terminated a 2001 memorandum of understanding known as MoU 44, a bilateral framework intended to manage overlapping maritime claims in the Gulf of Thailand and to allow the two countries to jointly develop offshore resources. The move removes one of the last structured channels for dialogue over a disputed maritime area that both Bangkok and Phnom Penh claim.
MoU 44 had produced little tangible progress after more than two decades and five rounds of talks, but it nevertheless functioned as a limited confidence-building mechanism. The waters in dispute include areas around several islands, notably Koh Kood, a Thai-controlled tourist destination believed to overlie significant, untapped oil and gas deposits.
Observers say the termination marks a shift away from cooperative resource sharing toward more unilateral, nationalist posturing. Pavin Chachavalpongpun, a professor at Kyoto University, described the cancellation as a significant regression in bilateral relations, moving the focus from joint management to assertions of sovereignty.
Under the memorandum, the two sides had agreed to share any energy gains in exchange for refraining from forcefully pressing territorial claims. The Thai government, however, argues that MoU 44 had become dormant and ineffective after decades of little progress and says the decision to end it is not connected to recent border violence.
The move comes amid a broader deterioration in ties after deadly clashes erupted along the roughly 800-kilometer land border last July. Fighting over contested parcels of territory has killed at least 150 people and displaced hundreds of thousands, producing a political crisis in Thailand that helped topple the Paetongtarn Shinawatra administration. In September a caretaker government led by Anutin Charnvirakul took power; he was later confirmed as prime minister in March.
Analysts say the border conflict has amplified nationalist politics on both sides. In Thailand the crisis has strengthened the military’s hand in its ongoing tug-of-war with civilian authorities, while Cambodia’s ruling party has used the dispute to portray itself as defending national sovereignty. Paul Chambers of the ISEAS–Yusof Ishak Institute noted that continued tensions benefit the Thai military by boosting pro-military nationalism and insulating the army from civilian oversight; critics say the new Thai leadership has shown little inclination to curb the military’s freedom to act.
In December, Thai forces struck casino and hotel complexes in Cambodia, asserting they were used as scam operations and by Cambodian military actors; Phnom Penh rejected those claims and said the strikes violated its sovereignty. Bangkok has also applied economic and military pressure at times to press its position.
Faced with a stronger neighbour, Cambodia has sought to internationalize the dispute, pursuing legal and diplomatic channels rather than relying on force. Phnom Penh has filed cases with the International Court of Justice and recently said it would initiate compulsory conciliation under the UN Convention on the Law of the Sea after Thailand moved away from MoU 44. Cambodia previously prevailed in a long-running ICJ case over the Preah Vihear temple, which bolsters its legal standing in international fora.
However, Cambodia’s appeals for international sympathy are complicated by its own reputational problems. Western governments and institutions have criticized the ruling Cambodian People’s Party for democratic backsliding, including the 2017 dissolution of the main opposition party. Reports of Chinese involvement at Ream Naval Base have also strained relations with the US and others, though Phnom Penh denies granting exclusive Chinese access.
More recently, Cambodia has become associated with large-scale transnational cyber-scam operations, an illicit industry that analysts estimate could be worth roughly $12.5 billion annually — about a third of the country’s formal GDP. That allegation, and high-profile reporting that labeled the country “Scambodia,” prompted an angry reaction from Cambodian officials who demanded corrections and apologies. The scandal and related sanctions — including measures last year by the US and UK against the Prince Group and its chairman, Chen Zhi — have further weakened Phnom Penh’s soft power.
Experts say these reputational liabilities limit Cambodia’s diplomatic room for maneuver in the West even as it courts support from powers such as China. Sophal Ear of Arizona State University observed that international law and third-party mechanisms are Cambodia’s strongest levers against a larger neighbour, which is why Phnom Penh is more willing to bring disputes before courts and international institutions.
Observers also note that international mediation efforts have been intermittent: Washington helped broker a brief ceasefire last year after threatening consequences, though the truce lasted only weeks and US attention has since waned. With MoU 44 ended, prospects for a negotiated, cooperative approach to the maritime claims have dimmed, raising the risk that resource competition and nationalist politics will further inflame bilateral tensions.