Thailand–Cambodia Row: From Legal Dispute to Energy‑Driven Standoff

By Pierre‑Yves Clais

PHNOM PENH — Beneath the surface of what appears to be a legal quarrel, the dispute between Thailand and Cambodia is now taking a worrying turn. As historical arguments resurface and references to international law multiply, another, even more decisive issue is coming to the fore: control over the Gulf of Thailand’s energy resources.

In this context, two Thai figures stand out for their activism and influence: Warong Dechgitvigrom and Panthep Puapongpan. Their positions help foster a lasting climate of tension between the two countries.

A systematic challenge to borders

A doctor turned politician, Warong Dechgitvigrom has become one of the main voices of a nationalist current determined to revisit the borders inherited from the colonial era. His argument, widely echoed in the Thai public space, rests on a central idea: the agreements concluded between France and Siam at the beginning of the twentieth century—especially the 1907 agreement—would be tainted with illegitimacy due to the colonial context in which they were negotiated.

By invoking UN General Assembly Resolution 1514, he argues that these territories should be re‑examined in the name of the right of peoples to self‑determination. Under this reading, several provinces that are now part of Cambodia are presented as historically linked to Thailand.

This political stance is matched by a more systematic approach from Panthep Puapongpan. An academic and activist, he focuses on deconstructing the legal foundations of the international decisions that set the current borders, proposing an alternative interpretation designed to undermine Cambodia’s position.

Preah Vihear at the heart of the dispute

The dispute over the Preah Vihear temple remains the pivot of this reasoning. The International Court of Justice had already ruled in favor of Cambodia in 1962, a decision later clarified and reaffirmed in 2013.

These judgments, based especially on the 1907 map and the principle of “estoppel,” are now being challenged by Panthep Puapongpan. In his view, the border should have followed the natural line of the cliff rather than the cartographic line drawn at the time. He concludes that certain areas adjacent to the temple were never properly attributed to Cambodia.

He also questions the validity of recent bilateral agreements, which he considers contrary to Thai constitutional law. In practical terms, this line of argument undermines the entire legal framework governing the two states’ border relations.

A gradually mobilized public opinion

These theses, repeated and amplified in the public debate, help spread the idea of a historical injustice that must be corrected. Long confined to narrow circles, this interpretation is now increasingly present in Thai society.

As this perception gains ground, the authorities’ room for maneuver shrinks. Any position perceived as conciliatory risks being interpreted as a surrender. The dispute, originally of a legal nature, has thus entered the sphere of domestic politics.

The Gulf of Thailand as the central issue

In this context, the question of the Gulf of Thailand has taken on decisive importance. The disputed area contains sizeable gas reserves that could weigh heavily on regional economic balances.

For Cambodia, the issue is that of development still largely to come. For Thailand, facing mounting pressure on its energy supplies and a slowing economy, these resources represent an immediate strategic opportunity.

This internal economic pressure cannot be ignored. The high level of Thai household indebtedness—close to 90 percent of GDP—weighs on consumption and limits the government’s margins of maneuver. While not a trigger in itself, this vulnerability acts as an accelerator: it strengthens interest in nearby, immediately exploitable resources capable of supporting the national economy.

Bangkok’s decision to withdraw from the bilateral cooperation framework, which until now allowed joint exploitation, marks a notable shift. It opens the way to a redefinition of the balance of power between the two sides.

The return of the military factor

In an already tense climate, the growing capabilities of the Royal Thai Navy attract particular attention. The modernization of the fleet, the strengthening of surveillance means, and the adaptation to offshore operations all reflect a clear determination to control maritime spaces.

Officially, the stated aim is to secure resources and shipping lanes. But in a context of border disputes, this evolution cannot be divorced from territorial issues.

On the ground, this posture is accompanied by mounting pressure on Cambodian civilians. In recent days, several fishermen have been boarded in contested waters. Presented as routine control operations, these interventions contribute to creating uncertainty and fear among local populations.

An incident revealing a hardening stance

The rise in tensions found a particularly worrying illustration on 29 April 2026, near the O’Smach border post in Oddar Meanchey province.

According to Cambodian authorities, repeated shots were fired from Thai territory between 10:35 and 11:09, while a delegation of foreign military attachés was conducting an inspection of the area. Nine impact points were recorded, resulting from the combined use of M79 grenade launchers and M16 assault rifles.

There were no casualties, but the incident forced international observers to interrupt their mission. Phnom Penh sees this as a clear violation of the ceasefire protocol signed in December 2025, which was intended to stabilize the region after the clashes of the previous summer.

The absence of an official explanation from Bangkok, combined with the very nature of the incident—occurring in the presence of foreign observers—heightens concerns about a possible change in the rules of engagement on the ground.

The risk of a fait accompli

In Phnom Penh, these developments are interpreted as signs of a gradual strategy. By weakening existing legal foundations while reinforcing its presence on the ground, Thailand could be trying to create the conditions for a fait accompli.

The prospect of unilateral exploitation of the Gulf’s resources, backed by enhanced maritime projection, no longer appears as a mere theoretical scenario.

Tensions expected to endure

The current situation is neither a misunderstanding nor a passing episode. It reflects a deeper transformation in the relations between the two countries, in which economic considerations now reinforce long‑standing territorial claims.

In this context, international law remains, in theory, an essential recourse for Cambodia. Yet the international experience invites a more sober assessment of its limits.

For nearly fifty‑two years, about 38 percent of Cyprus’s territory has remained under Turkish occupation. This situation has been repeatedly condemned by the international community, notably by UN Security Council Resolutions 353, 541, and 550, as well as by General Assembly Resolution 3212. No state outside Ankara recognizes the legality of this occupation.

Yet, more than half a century later, nothing has changed. Cyprus, a member of the European Union, remains partially occupied, despite the weight of European and UN institutions.

The conclusion, harsh but difficult to refute, is that the international system records legal violations; it does not necessarily prevent them, let alone correct them.

For a country like Cambodia, the lesson is clear. In the border dispute with Thailand, ASEAN has revealed its limits, while UN mechanisms remain largely ineffective. As for the International Court of Justice, whose 1962 and 2013 rulings on Preah Vihear are binding, it has no enforcement mechanism against a state that contests the scope of those judgments.

Waiting for institutional reactions is not a policy. It is, on the contrary, the risk of a gradual erosion of de facto positions on the ground.

Phnom Penh will therefore need a more active and creative approach. This means moving beyond the regional framework alone, building bilateral support networks, using economic partnerships and major infrastructure projects as leverage, and rigorously documenting every incident in order to build an irrefutable file when the time comes.

It also requires understanding that, beyond military capacity, international credibility, control of the narrative, and diplomatic consistency remain essential tools for a medium‑sized state.

The Cypriot example serves as a warning: being in the right does not guarantee recognition. A territory recognized on paper can, for a long time, remain outside the effective control of the state to which it belongs.

It is precisely this scenario that Cambodia must now seek to avoid.