Thailand shows foolish ambitions in international law and violates Cambodian sovereignty if it cancels two MoUs with Cambodia

By Cambodia Daily
After more than two months of border disputes sparked by Thailand, Thailand’s new Prime Minister Anutin Charnvirakul has claimed that his government plans to hold a national referendum to decide whether to cancel two Memoranda of Understanding (MOU) with Cambodia.

This statement shows that Thailand’s ambitions are ignorant of international law and grossly violate Cambodia’s sovereignty, because the agreement is in accordance with national and international law.

Based on the Franco-Siamese Conventions and Treaties of 1904 and 1907 and the 1908 Appendix I Map, both the 2000 MoU on land borders and the 2001 MoU on water borders agreed upon by both parties are in accordance with national and international law.

Based on the two MoUs that were established, the aim is to seek peaceful border demarcation based on international law and without compromising the sovereignty of the two countries that have agreed to it.

Political science expert Dr. In Sophal wrote on his Facebook account that according to international law, the 1969 Vienna Convention on the Law of Treaties when two sovereign states sign and ratify a Memorandum of Understanding (MOU) for implementation, that memorandum is considered valid under international law.
He said that based on the Vienna Convention, a state cannot unilaterally withdraw from an agreement unless the agreement or MoU stipulates the conditions for its termination, while the 2000 and 2001 MOUs do not. The validity of the Cambodia-Thailand Memorandum of Understanding has not been determined. The Thai government may unilaterally declare that it does not recognize the 2000 and 2001 Memorandums of Understanding with Cambodia. But according to international law, such a declaration cannot negate Thailand’s obligations towards Cambodia if the Cambodian side demands continued implementation.

He added that if the Thai side unilaterally withdraws from the Memorandum of Understanding (MOU) with Cambodia, the Cambodian side can lodge a diplomatic complaint with the United Nations (UN) or ASEAN and can also file a complaint on the matter with the International Court of Justice (ICJ).

Lawyer Sok Sam Oeun said that violating the agreement is something that the violator can do, but must also face the negative consequences that arise from violating the agreement.

He said that those who violate agreements between countries may be condemned by the international community, who may impose diplomatic and economic sanctions. But if the country that is the aggressor is very powerful, that is, has a strong economy and a strong military, for example, like Russia, everyone can see that small countries do not dare to impose sanctions on them.
He said that if Thailand dares to cancel the agreement, it will be faced with the question of whether there are any countries in the world that would dare to put diplomatic and economic pressure on its own country? If there is a pressure crowd, will it be able to withstand its economic downturn?
Lawyer Sok Sam Oeun claims that regarding the dispute between Thailand and Cambodia, Cambodia can resort to international judicial mechanisms if Thailand violates the agreement, but at the same time, Cambodia must not forget to strengthen its military because if this happens, there could be a war between Thailand and Cambodia.
Looking back at the foolish ambitions of international law, Thailand’s land area is 513,120 square kilometers, ranking third after Indonesia and Myanmar. But Thailand still has ambitions to continue without any knowledge of international law. Thailand has violated international law and treaties under Article 26 of the Vienna Convention on the Law of Treaties, which Thailand, as a signatory, is obligated to respect.
Thailand’s withdrawal from the MoU would:
• Seriously damage its legal credibility on the international stage.
• Be seen as undermining the rule of law, particularly in the ASEAN Charter and the UN Charter.
• Weakened leadership role in the region.
• Damaged relations with neighboring countries.
• Threatened with expulsion from the United Nations as in 1962 after Thailand failed to respect the ICJ ruling and opened the door to outside powers (For example: China, the United States) influence regional politics, contrary to ASEAN principles, which these two powers, as well as permanent members of the UNSC, have been and are turning to for legal support on the Cambodian side.
Overall, it is best for Thailand to continue to maintain and implement the existing MoU, including continuing bilateral negotiations, technical demarcation under the Joint Boundary Commission (JBC). Peaceful dispute resolution mechanisms, including the ASEAN framework and international coordination, if necessary.

As for Cambodia, it has already filed a complaint with the ICJ on June 15, 2025, but the plan to proceed must already prepare strong evidence to the United Nations Security Council (UNSC). In the event that Thailand uses military force to invade after canceling these two MoUs. Using the ICJ or ITLOS legal system, Cambodia should quickly ratify the 1982 UNCLOS to challenge Thailand’s withdrawal from the MoU.