Expert Warns Thailand Could Face ICJ Case if MOU43-44 Cancelled

Picture courtesy of Khaosod

Associate Professor Akrapong Kamkoon, former dean of Thammasat University’s Pridi Banomyong International College, has raised concerns that Thailand could face legal action at the International Court of Justice (ICJ) over any unilateral cancellation of MOU43 and MOU44 with Cambodia. The warning comes amid claims that Thailand may cancel the agreements unilaterally, citing the 1969 Vienna Convention on the Law of Treaties (VCLT), which allows parties to terminate treaties if the other party materially breaches the agreement.

MOU 43 and MOU 44 are two memoranda of understanding signed between Thailand and Cambodia in 2000 and 2001, respectively, to manage and cooperate on the demarcation of their land and maritime boundaries. MOU 43 (2000) concerns the land border, setting guidelines for joint boundary surveys and mapping, particularly in disputed areas where tensions have flared in the past. 

MOU 44 (2001) addresses the overlapping maritime claims in the Gulf of Thailand, providing a framework for negotiations on resource exploration and delimitation of the continental shelf. While both agreements aim to promote peaceful resolution and joint cooperation, they have been politically sensitive in Thailand, with critics arguing that they may disadvantage Thai sovereignty, especially regarding resource-rich border zones.

Akrapong stressed that the VCLT’s concept of “material breach” must be assessed based on the treaty’s provisions, determining whether any alleged violations undermine the treaty’s main objectives. He cautioned that canceling the MOUs without evidence of a serious breach by Cambodia could create a new international dispute and potentially trigger litigation at the ICJ, citing the 1997 Gabčíkovo–Nagymaros Project case as an example.

The discussion followed allegations that Cambodian forces had used military aggression and weaponry inside Thai territory between 24–28 July 2025, causing civilian casualties, property damage and violations of specific MOU clauses. Akrapong emphasised that while such actions warrant urgent response under Thai law, they do not automatically justify unilateral treaty termination under international law.

He warned that an incorrect approach could escalate the dispute further, possibly drawing in third-party states unnecessarily. Although Thailand is not a formal party to the VCLT, its provisions are considered customary international law and carry legal weight. Akrapong urged careful legal consideration before any unilateral cancellation to avoid creating additional international complications.

Key Takeaways

• Unilateral cancellation of MOU43-44 could trigger a new dispute and ICJ litigation if Cambodia is not proven to have materially breached the agreements.

• Alleged Cambodian military actions inside Thai territory do not automatically justify termination under international law.

• Thailand, though not a VCLT party, is bound by its customary international law provisions, requiring cautious legal assessment.

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  Adapted by Asean Now From Khaosod 2025-10-16