The simmering border dispute between Thailand and Cambodia has plunged into its deepest crisis in years, revealing a potent mix of unresolved historical grievances, asymmetric economic interdependence and a dramatic breakdown of trust at the highest political levels. What began as a deadly skirmish has spiralled into a full-spectrum standoff, threatening not only regional stability but also the livelihoods of ordinary citizens caught in the crossfire.
Root causes: Cartography, colonialism and contesting claims
The core of the enduring conflict lies in a fundamental disagreement over cartography and the legacy of French colonialism. Cambodia steadfastly adheres to the 1:200,000-scale maps from the 1904 and 1907 Franco-Siamese Conventions, particularly the Annex I map that explicitly placed the Preah Vihear temple within its territory. This demarcation was famously upheld by the 1962 International Court of Justice (ICJ) ruling, and Cambodia views these maps as legally binding.
Thailand, conversely, champions its own, more detailed 1:50,000-scale national maps, arguing they more accurately reflect the true topography and the watershed principle, which was the intended basis for border delimitation. This cartographic clash, stemming from differing projection systems and scales, creates vast “grey zones” along their 817 km shared frontier, acting as perpetual flashpoints. The lack of a mutually agreed-upon demarcation has fuelled recurrent armed clashes, notably between 2008 and 2011.
Cambodia’s recent decision to push for ICJ interpretation on four additional disputed temple areas (the Emerald Triangle, Ta Moan Thom temple, Ta Moan Toch temple and Ta Krabei temple) signals its profound frustration with the stalled bilateral Joint Boundary Commission (JBC) talks, a step Thailand vehemently opposes, preferring direct negotiation.
Beyond maps, internal politics and nationalism in both countries serve as significant root causes, often used by political elites to consolidate power or divert attention from domestic issues.
Reactions: Escalation, leverage, and shattered trust
The current crisis escalated rapidly following a May 28, 2025, skirmish in the disputed Emerald Triangle that resulted in the death of a Cambodian soldier. Reactions from both sides have been a tit-for-tat escalation:
● Thailand’s economic leverage: Thailand has imposed restrictions at border crossings, impacting trade and the movement of people. This highlights its significant economic leverage over Cambodia. Hundreds of thousands of Cambodian migrant workers (approximately 500,000, with over 400,000 legally registered) are vital to Cambodia, sending back substantial remittances (e.g., $1.25 billion in 2022). These workers also fill crucial labour shortages in Thailand.
● Cambodia’s counter-threats: In response, Cambodia’s leaders have reacted strongly, including appealing to its migrant workers to return home (though many pragmatically remain due to significantly higher wages and better living standards, public services, infrastructure and healthcare in Thailand). Cambodia has also threatened to disconnect cross-border internet links, cut off electricity supplies, and even halt PTT (Petroleum Authority of Thailand) fuel services, alongside bans on Thai movies, TV shows, and imports. The threat to cut off services has been widely reported.
● The ‘unprofessional’ leak: The diplomatic spat reached a boiling point when Thai Prime Minister Paetongtarn Shinawatra publicly criticised Cambodian leaders on June 16, labelling their actions, particularly their reliance on social media for diplomatic communications, as “unprofessional”. This public accusation drew a swift and strong rebuke from Cambodian Prime Minister Hun Manet. In a dramatic counter-move, Cambodian Senate president Hun Sen subsequently leaked a June 15 private phone conversation between himself and Paetongtarn. Hun Sen claimed the leak was for “transparency” following Paetongtarn’s public slight. The leaked audio, which appeared to show Paetongtarn criticising a Thai military commander (Lieutenant General Boonsin Padklang, commander of the Second Army Region), plunged her into a severe domestic political crisis, forcing her to make public apologies and mend fences with the powerful Thai military. For Hun Sen, the act was a calculated response to Paetongtarn’s initial public slight.
● Shattered personal bonds: This very public exchange has irrevocably shattered the “god-brother” bond that for over 30 years united Hun Sen and the Shinawatra family. Hun Sen’s stark declaration that the “30-year relationship was destroyed” signals a profound breakdown in trust, casting a long shadow over future informal negotiations.
● Geopolitical undercurrents: The conflict is increasingly viewed through a “China-trained vs US-trained armies” lens. Cambodia has notably deepened its military ties with China, including acquiring tanks, armoured vehicles and air defence systems, and engaging in large-scale joint exercises like “Golden Dragon 2025”, especially after US military aid was curtailed due to human rights issues. Thailand, a long-standing US treaty ally and participant in major drills like “Cobra Gold 2025”, has also diversified its military procurement (e.g., Chinese submarines and tanks) and increased joint exercises with China, creating a delicate balancing act.
● Media and public opinion: Both Thai and Cambodian media contribute to the “colouring” of the dispute. Thai outlets like the Bangkok Post and The Nation Thailand, while generally adhering to journalistic standards, tend to emphasise Thai sovereignty and portray Cambodian actions as escalatory. A recent NIDA poll indicates that within Thailand, trust in the military to handle the dispute often surpasses that in the government. Meanwhile, in Cambodia, a recent Asia Vision Institute (AVI) survey (June 18, 2025) reported overwhelming public support (over 93.6%) for the Cambodian government’s handling of the dispute. Specifically, 99.8% of Cambodians supported taking the four disputed areas to the ICJ, and 73.8% believed the conflict was provoked by the Thai military. This strong domestic backing empowers the Cambodian government to maintain its firm stance.
Future: A rocky road with glimmers of hope
The immediate future of Thailand-Cambodia relations appears fraught with tension. With nationalistic sentiment mobilised on both sides, making significant compromises is politically challenging for either government.
● Continued stalemate on border demarcation: The fundamental disagreement over maps and the preferred mechanisms for resolution (ICJ vs. bilateral talks) will likely keep the border dispute simmering, with periodic flare-ups. Cambodia’s push for the ICJ may introduce further legal complexities that Thailand continues to resist.
● Economic interdependence as a stabiliser (and source of leverage): While a source of tension, the deep economic ties, particularly migrant labour, also act as a de-escalating factor. Neither country can afford a complete severing of these ties without significant self-inflicted harm. The reluctance of Cambodian workers to leave Thailand underscores the enduring economic realities.
● Impact of domestic politics: The political stability in Thailand, particularly PM Paetongtarn’s ability to navigate the current domestic crisis and maintain the military’s confidence, will significantly influence Thailand’s approach to the dispute. Similarly, Cambodia’s leadership under Hun Manet continues to consolidate power, and a firm stance on the border may serve internal political objectives.
● Role of ASEAN and the international community: While ASEAN’s non-interference principle limits its direct intervention, regional stability is a shared concern. The international community will likely continue to call for restraint and peaceful resolution.
● Long-term path: A lasting peace requires both nations to move beyond blame and embrace genuine dialogue. This could involve exploring new, mutually acceptable mechanisms for border demarcation that acknowledge the historical complexities, or a willingness to abide by international legal rulings. Collaborative economic projects that benefit border communities could also help build trust. However, such a path demands a level of political will and compromise that appears scarce amidst the current diplomatic firestorm.
The Preah Vihear precipice is a test of regional diplomacy. Its resolution hinges not just on legal arguments or military posturing, but on the capacity of both nations to prioritise long-term stability and mutual prosperity over short-term political gains and historical grievances.
Vichana Sar is a researcher based at the Royal Academy of Cambodia. The views and opinions expressed are his own.