Samdech Techo Hun Sen Questions Thailand’s Move to Cancel Maritime MoU

(Phnom Penh): Cambodia’s Acting Head of State, Samdech Techo Hun Sen, raised concerns over Thailand’s reported efforts to cancel the 2001 Memorandum of Understanding (MoU) on overlapping maritime claims, warning the move contradicts its own calls for bilateral dialogue. Samdech Techo wrote in his social media on Friday (May 1) as follows: “In the past, many Thai scholars, analysts, and researchers have frequently discussed and analyzed the Memorandum of Understanding (MoU) on the overlapping maritime area between Cambodia and Thailand. These analyses generally tend to oppose its cancellation, and I would like to express my respect for those views. Today, I would like to share the full article (unofficial translation) by Dr. Surachart Bamrungsuk, an expert in international relations and security in Thailand. I would like to apologize to Dr. Surachart Bamrungsuk for reposting his article, with the aim of helping the people of Cambodia and Thailand better understand this MoU. Thailand has been attempting and is continuing to push for the cancellation of the MoU on the overlapping maritime area signed between Cambodia and Thailand. This stands in stark contrast to what the Thai side has previously sought in bilateral negotiations with Cambodia. Is Thailand trying to internationalize the overlapping maritime boundary with Cambodia?” At the same time, Samdech Techo Hun Sen shared the full content of an article by Dr. Surachart Bamrungsuk, an expert in international relations and security, titled “Let Us Be Glad—Cancel MoU 44!”, which was published on the “Matichon Weekly” page on 30 April 2026: The article borrows its title from a song by the Suntaraporn band, “Let Us Be Glad,” to reflect the Thai government’s decision under Prime Minister Anutin Charnvirakul to cancel “MoU 44,” formally known as the Memorandum of Understanding on claims over the overlapping maritime area, signed on 18 June 2001. This decision is seen as creating a sense of satisfaction among certain nationalist groups within Thai society. However, whether Thai society will truly feel “glad” after the cancellation remains a question worth considering. Several observations arise following the move: The Thailand–Cambodia Memorandum of Understanding (MoU 2544) had previously been declared canceled in November 2009 under Prime Minister Abhisit Vejjajiva, following a proposal by then-Foreign Minister Kasit Piromya. However, that cancellation was ineffective, as it was not formally notified to Cambodia and was not processed through parliament, rendering it incomplete. Any cancellation of such an MoU must follow procedures outlined in the 1969 Vienna Convention on the Law of Treaties; it cannot simply be declared void unilaterally. The 2009 cancellation stemmed from tensions related to Cambodia’s appointment of Thaksin Shinawatra as an economic advisor, alongside disputes over the Preah Vihear Temple. At that time, the cancellation served as a symbolic protest against Cambodia. The justification that negotiations under the MoU had made “no progress” was used in 2009 and has resurfaced again in 2026, raising questions about its validity. Since the Yingluck Shinawatra administration did not proceed with formal cancellation, the MoU has remained in force until now, though it is once again facing termination. The current decision to cancel MoU 44 can be interpreted as a consequence of Thailand–Cambodia conflicts occurring twice in 2025, and as a reflection of strong nationalist currents within Thai political leadership. Such conflicts have fueled renewed nationalist sentiment in Thailand, particularly among groups previously active during the 2008 Preah Vihear dispute. This resurgence has contributed to political support for the Bhumjaithai Party and influenced the current government’s stance.  It remains unclear whether other factors are driving the cancellation beyond the desire to project a nationalist image and appeal to hardline groups, as no other interfering issues appear evident—unlike the situation in 2009, when the Thai government was dissatisfied with Cambodia’s appointment of an advisor. The argument that canceling the MoU would allow both countries to rely on the United Nations Convention on the Law of the Sea (UNCLOS 1982) appears “absurd,” as MoU 44 itself is already grounded in maritime law principles. Canceling the MoU would force both sides to establish a new “provisional arrangement” framework for negotiations, effectively recreating a mechanism similar to the existing one—raising doubts about how progress would be achieved. It is important to note that MoU 44 serves as a negotiation mechanism, not as a treaty for dividing oil and gas resources in the Gulf of Thailand. Its cancellation removes the negotiation framework and the joint committee overseeing discussions. Negotiations under the MoU do not affect Thailand’s maritime claims, nor does the MoU undermine those claims, contrary to assertions by extreme nationalist groups. Foreign Minister Sihasak Phuangketkeow, along with officials in the Department of Treaties and Legal Affairs at both director-general and deputy director-general levels, should clearly understand the benefits of MoU 44. At the very least, these four individuals have all previously worked under former Foreign Minister Surakiart Sathirathai, and none of them have ever expressed opposition to this MoU. In particular, Sihasak Phuangketkeow, who formerly served as Permanent Secretary of the Ministry of Foreign Affairs, should have a thorough understanding of the matter, and he has never taken a stance against the MoU in the past. I would like to see the professionalism and integrity of former officials in the three key relevant institutions demonstrated, by speaking the truth regarding the MoU issue. These institutions are: 1) the Department of Treaties and International Law of the Ministry of Foreign Affairs, 2) the Military Mapping Department, and 3) the Hydrographic Department of the Royal Thai Navy, particularly the third, as the author himself previously worked there and played a significant role in developing the framework of MoU 44, with the exception of current naval officers in positions of authority. I clearly understand that such opposition is unlikely to change the Prime Minister’s decision to cancel MoU 44, as he needs to appease hardline nationalist groups and demonstrate his image as a “nationalist” to the public. However, “extreme nationalist politics” may only be useful during election campaigns. If it is used as a primary factor in shaping Thailand’s foreign policy, it is likely to create more problems than benefits. Finally, I would like to emphasize that the Prime Minister’s decision has seriously affected Thailand’s “national interests,” as canceling MoU 44 effectively means abandoning Thailand’s maritime interests from the perspective of international law, given that previous negotiations had already established a framework. Unless Prime Minister Anutin’s government firmly believes it can create a new maritime negotiation framework that is better than the previous one, or believes it possesses experts with greater knowledge and experience in maritime law than figures such as Professor Dr. Surakiart Sathirathai and Admiral Thanom Charoenlap, I, unfortunately, do not believe so—and find it difficult to do so. After hearing from those within the government, the public, the Ministry of Foreign Affairs, and the Royal Thai Navy, my lack of confidence has only deepened. I would like to see government leaders study analytical works on MoU 44 written by Professor Dr. Surakiart Sathirathai, published in two volumes in 2011, as well as the analysis by Admiral Thanom Charoenlap published in 2012. All three volumes were republished in 2024. I do not wish to see Thai leaders become overly influenced or emotionally absorbed by the “rhetoric” of extreme nationalist groups that lack any grounding in principles of international law.=FRESH NEWS