PHNOM PENH, December 21, 2025 — In a stinging open letter released on social media, H.E. Jean-François Tain, Minister Delegate attached to the Prime Minister for Foreign Affairs, has formally accused the Thai State of a “planned and deliberate” military offensive. Detailing the crisis that began on December 7, Tain argued that the current hostilities represent a systematic Thai aggression against Cambodia 2025 rather than a mere border skirmish.
The letter, which has quickly gained international attention, outlines five “fundamental truths” that the Minister says the global community must acknowledge to uphold the rule of law.
Open letter
Since 7 December 2025, Cambodia has been the target of an open and deliberate military aggression by the Thai armed forces along its western border. This is neither an isolated incident, nor an accidental clash, nor an uncontrolled escalation. It is a war that has been planned, acknowledged, and carried out by the Thai State.
Land, air, and naval forces have been deployed simultaneously. Wherever the Thai army advances, it plants its flag on Cambodian soil. The attacks strike not only military positions but also civilians, essential infrastructure, temples, and historic Khmer monuments. Considering these facts, five fundamental truths must be stated.
1. Cambodia cannot be the aggressor
A small country in terms of territory, military resources, and ambitions, Cambodia neither has the capacity nor the intention to attack a neighbor three times more powerful. Cambodia has consistently shown restraint and has continuously called for a peaceful settlement of border disputes, from well before the first armed clash to its acceptance of the ceasefire of 28 July 2025 and the Joint Declaration for Peace of 26 October 2025. Had Cambodia truly sought war, why would it have devoted such sustained efforts since 1998 to reconstruction, national reconciliation, and peacebuilding?
2. The law is on Cambodia’s side
In its pursuit of a complete and peaceful border delimitation founded on friendship and mutual development, Cambodia relies on legally established border maps and treaties recognized by the international community. This includes the Franco-Siamese Treaties of 1904 and 1907, as well as the Memorandum of Understanding of 2000. Thailand, by contrast, relies on unilateral maps produced and recognized by itself alone. Under these circumstances, there is no basis for claiming that Cambodia intended to violate Thailand’s territorial sovereignty.
3. Cambodia chooses the law; Thailand chooses weapons
During the border disputes of 1954, 2008, and again in the recent events of July 2025, Cambodia has consistently chosen to resort to legal mechanisms and international law. The International Court of Justice ruled, in 1962 and again in 2013, in favor of Cambodian sovereignty over Preah Vihear and its surrounding areas. It would therefore be illogical and irrational for Cambodia to abandon the rule of law and embark on a war of aggression against Thailand.
4. Cambodia knows the cost of war
Scarred by two wars and a genocide between 1970 and 1998, Cambodia places peace, stability, and socio-economic development at the very top of its national priorities. This commitment has been recognized by the international community, notably through the awarding of the World Peace Prize in 2021, the Peace Prize for Humanity and the Planet in 2024, and an ASEAN award in 2025. There is thus no reason for Cambodia to seek to destroy a hard-won peace by attacking a neighboring country.
5. Thailand has declared and waged the war
Since the resumption of hostilities on 7 December 2025, Thai authorities have publicly ordered large-scale military operations. These offensives extend along more than 800 kilometers of land border, with incursions reaching 80 to 90 kilometers deep into Cambodian territory. They involve the use of F-16 and Gripen fighter jets, cluster munitions, armed drones, heavy artillery, long-range rockets, tanks and armored vehicles, as well as the coordinated deployment of land, air, and naval forces. These attacks do not target military positions alone. They also strike innocent civilians, roads, schools, pagodas, homes, refugee camps, and Khmer temples and historical monuments, some of which are listed as World Heritage sites. These acts cannot be characterized as an exercise of the right of self-defence under international law; they constitute a deliberate and manifest armed aggression against the sovereignty and territorial integrity of the Kingdom of Cambodia.
We call upon the international community to name this aggression for what it is, to uphold international law, and to assume its responsibilities. Silence, inaction, or ambiguity would only embolden further violations and legitimize the unlawful use of force over the rule of law. What is at stake is not only Cambodia’s sovereignty, but the very credibility of the international order founded on the rule of law.
READ MORE: “We Refuse Erasure”: Minister Jean-François Tain Condemns Thai Aggression Against Cambodia