Border Clash Threatens Pheu Thai’s Energy Plans in Gulf

On May 28, while the ruling Pheu Thai Party sought parliamentary support for its new budget—and amid mounting tensions with its largest coalition partner, Bhum Jai Thai Party—a border clash broke out between Thai and Cambodian forces, resulting in the death of one Cambodian soldier, Sgt. Suan Roan.

Military and political leaders have since de-escalated the situation, and a full-blown conflict appears unlikely, particularly given the strong ties between the countries’ top leadership, including former prime ministers Hun Sen and Thaksin Shinawatra.

The clash at Chong Bok, located in the disputed Emerald Triangle, erupted after several months of increasing tensions. In early February, a group of Cambodian visitors sang their national anthem at the ancient Khmer-Hindu Ta Muen Thom Temple, drawing the intervention of Thai soldiers. The group reportedly included the wife of a senior Cambodian soldier. Ta Muen Thom’s ownership is disputed, with Cambodia citing a 1907 French colonial-era map to justify its claim while Thailand relies on maps from the Royal Thai Survey Department.

Later in February, tensions escalated further when a controversial fire destroyed the Trimuak Pavilion, a small religious site in Chong Bok, located 275 km from Ta Muen Thom. The Trimuak Pavilion, though small, holds significant historical weight. Constructed in the early 1990s through a tripartite effort involving soldiers from Laos, Cambodia, and Thailand, the pavilion features a distinctive three-sided gable roof, each side bearing a national symbol from one of the three countries.

Beyond its architectural features, the pavilion stood as a symbol of regional reconciliation. It reflected the shift in Thai foreign policy under then-Prime Minister Gen. Chatchai Choonhavan, who sought to transform Indochina “from a battlefield into a marketplace.” In the late 1980s, the area around Chong Bok had been the scene of fierce fighting among Thai, Khmer Rouge, Cambodian, and Vietnamese forces.

That vision of cooperation was embodied in the pavilion’s construction, which was coordinated by Lt. Gen. Issarapong Noonpakdee, then commander of the 2nd Army Region. Ironically, Issarapong later helped topple Chatchai in a coup and briefly served as Army Commander-in-Chief. His legacy remains relevant today: his son, Gen. Songwit Noonpakdee, is now Supreme Commander of the Thai Armed Forces and heads the Border Threat Mitigation Center, serving as a crucial link between the military and civilian leadership.

It remains unclear whether these incidents were isolated or part of an orchestrated campaign by elite string-pullers to advance a self-serving or narrowly nationalist agenda—see the 2008–2011 Preah Vihear Temple crisis. Either way, the renewed land border tensions risk further complicating the economically critical negotiations over the Overlapping Claims Area (OCA) in the Gulf of Thailand, which is among the Pheu Thai government’s top ten priorities. The 27,000 km² OCA is believed to contain roughly 11 trillion cubic feet of natural gas, worth an estimated $300 billion.

Despite past frictions, both governments have expressed a willingness to cooperate. In 2001, a memorandum of understanding was signed by the foreign ministers of Hun Sen and Thaksin Shinawatra, establishing a framework and a Joint Technical Committee (JTC) to negotiate maritime boundaries and resource development. The OCA regained momentum during the Prayuth Chan-ocha government but has since stalled under the Pheu Thai-led government.

PM Paetongtarn pledged in November 2024 that her Cabinet would take up the JTC appointments within weeks, but nothing materialized. Cambodia has stated it is ready and waiting for its Thai counterparts. During her official two-day visit to Cambodia in April, the OCA was absent from the agenda, and she made no substantive comments to the media. When asked, Paetongtarn deflected, directing reporters to the TV Pool’s meeting readout.

While the government may be prioritising other matters, such as the casino bill, over the politically sensitive OCA, its continued stonewalling raises questions about whether other actors and interests are also holding back the JTC appointments. With attention now diverted to rising tensions on the land border, the prospect of renewed progress on the OCA appears more distant than ever.