A powder keg ignited: Thailand and Cambodia must defuse border tensions now

The roots of this crisis run deep. Colonial cartography laid the groundwork for future disputes, particularly in sensitive areas surrounding the Preah Vihear and Ta Muen Thom temples. While the International Court of Justice (ICJ) awarded Preah Vihear to Cambodia in 1962 and reaffirmed this ruling in 2013, ambiguities persist along other parts of the frontier. These gray zones have become fertile ground for nationalist rhetoric and military confrontation.

From February through May 2025, skirmishes increased markedly. A Cambodian soldier was killed in a border exchange on May 28. Then, in mid-July, several Thai soldiers were injured by landmines that Thai officials allege were newly planted by Cambodian forces. These incidents triggered a cascade of diplomatic actions—Thailand recalled its ambassador, sealed border checkpoints, and curbed cross-border travel. Tensions snowballed, leading to the latest military exchange in July that involved rocket and artillery fire, followed by Thai F-16 airstrikes targeting Cambodian military positions.

This sequence of hostilities—from mines to mortars, artillery to airstrikes—reflects a dangerous trajectory. Each incident escalates the next, in a destructive feedback loop where dialogue is replaced by firepower and diplomacy is eclipsed by domestic politics.

Inside Thailand, political pressure is mounting. Former Prime Minister Paetongtarn Shinawatra came under intense criticism following a leaked phone call with former Cambodian leader Hun Sen, an episode that inflamed nationalist outrage and ultimately cost her coalition its parliamentary majority. In Cambodia, Prime Minister Hun Manet has drawn upon historical grievances to strengthen his domestic standing, mobilizing public sentiment and instituting a new wave of military conscription. Both governments appear more preoccupied with political survival than crisis de-escalation.

Efforts to contain the conflict through diplomatic channels have faltered. Cambodia has petitioned the ICJ for intervention, but Thailand has rejected further adjudication. ASEAN, for its part, has once again proven institutionally incapable of rising to the challenge. While regional actors such as China and Malaysia have issued calls for calm, they have stopped short of proposing—or enforcing—concrete mechanisms for ceasefire or resolution.

Meanwhile, the real cost of this crisis is borne by civilians. Villages near the border have been struck by rocket fire, damaging homes, gas stations, hospitals, and places of worship. Entire communities in Thailand’s northeastern provinces have begun evacuating. Though governments talk of sovereignty and justice, it is border residents—on both sides—who pay the price for the failure of leadership and diplomacy.

This situation is unsustainable and deeply dangerous. Four immediate steps must be prioritized.

First, a ceasefire must be negotiated and monitored by a credible third party. Whether through ASEAN, the UN, or neutral military observers, external verification is essential to prevent further miscalculations.

Second, demilitarization around sacred and sensitive zones—especially near Preah Vihear and Ta Muen Thom—is urgently needed. These historical and cultural sites must not be transformed into theaters of war.

Third, backchannel diplomacy should be revived and intensified. Both governments must signal a willingness to return to talks—whether bilaterally or through international mechanisms like the ICJ. Sovereignty disputes cannot be settled through artillery barrages.

Fourth, humanitarian assistance must flow to affected communities. Displaced Thai and Cambodian villagers need shelter, food, and basic medical services. This should be depoliticized and coordinated by neutral relief agencies to ensure impartiality and efficiency.

Beyond the bilateral dimension, this crisis is a litmus test for ASEAN’s cohesion and credibility. If ASEAN cannot respond effectively to such a serious regional threat, then its claims to centrality and relevance are severely undermined. The Cambodia–Thailand standoff may appear contained for now, but history teaches that border disputes, if mishandled, can metastasize into broader regional conflagrations.

There is still a window for peace—but it is rapidly narrowing. Thailand and Cambodia must pull back from the brink. Their leaders must resist the temptation of using military escalation as a political tool, and instead prioritize long-term stability over short-term applause. Both countries share more than a border—they share a responsibility to future generations to resolve disputes through dialogue, not destruction.

ASEAN, too, must act decisively. Words are no longer sufficient. If regional mechanisms are to have any relevance, this is the moment to demonstrate resolve, creativity, and unity.

The choice before us is stark: either ASEAN helps facilitate a return to peace, or Southeast Asia edges closer to a conflict that no one can afford.

Let wisdom prevail before the next explosion costs us more than diplomacy ever will.

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Phar Kim Beng is Professor of ASEAN Studies at International Islamic University Malaysia (IIUM) and Director at Institute of Internationalization and ASEAN Studies (IINTAS)