Surachart: Thailand Must Not Abandon Treaties Defining Eastern Border

Surachart: Thailand Must Not Abandon Treaties Defining Eastern Border

BANGKOK, June 5, 2026 — Prominent Thai security and geopolitical expert Surachart Bamrungsuk has warned that Prime Minister Anutin Charnvirakul’s recent remarks on the Cambodia-Thailand border dispute could expose Thailand to significant legal risks and potentially repeat mistakes that contributed to previous defeats before the International Court of Justice (ICJ).

In an article titled “Cambodia’s Trap! Is Anutin Leading Thailand Toward Another Defeat at the International Court?”, Surachart responded to Anutin’s May 27 statement that Thailand would only recognize 1:50,000-scale maps and saw no reason to negotiate if Cambodia continued relying on the 1:200,000-scale maps historically associated with the Franco-Siamese boundary settlement.

According to Surachart, many Thai academics and analysts immediately expressed concern, warning that such a position could draw Thailand into a legal trap. He argued that the issue is not about map scale, but rather about which documents possess legal standing under international law.

The scholar explained that the Cambodia-Thailand border originates from a series of treaties signed between Siam and France in the early twentieth century. Following those agreements, a joint boundary commission conducted surveys and produced official delimitation maps that were completed in Paris and transmitted to the Siamese government in 1908.

Those maps, commonly known as the boundary delimitation maps, were produced at a scale of 1:200,000. Surachart noted that the 1:50,000 maps cited by some Thai officials were created much later, largely for military and operational purposes during the Cold War era, and were never jointly approved or ratified by both countries.

He emphasized that international courts assess legal validity rather than cartographic detail. While the 1:50,000 maps may appear more precise, they do not carry the same legal status because they were not mutually recognized by Cambodia and Thailand.

Surachart further pointed to a disclaimer printed on the 1:50,000 military maps stating that the “boundary representation is not necessarily authoritative.” In his view, relying on such maps in an international legal forum would significantly weaken Thailand’s position because the maps themselves acknowledge that the depicted boundary is not official.

The academic cited international jurisprudence, including border disputes adjudicated by the ICJ, where maps were considered supporting evidence only when linked to treaties or accepted by both parties. He argued that legal recognition and treaty obligations carry greater weight than technical precision.

Surachart also rejected suggestions that Thailand should simply abandon the historical treaties and associated boundary maps altogether. Such a move, he warned, would create far-reaching consequences because the same treaty framework not only governs the Cambodia-Thailand border but also underpins Thailand’s eastern boundary with Laos.

According to the analyst, discarding the treaty-based framework could destabilize established borders and create new uncertainties over territories that Thailand already regards as legally settled. He described the idea as both impractical and potentially damaging to Thailand’s long-term national interests.

The article reflects growing debate within Thailand’s academic and strategic community over the legal implications of border policy and the importance of maintaining positions consistent with international law and existing treaty obligations.