Written by: Agnes Audrey Valerie, Alifia Nur Khalisa, & Olivia Amabel H. L. Tobing
Research and Analysis Division – FPCI Chapter UI Board of 2025
General Overview
What began as a struggle over an ancient temple has evolved into a persistent challenge of regional stability. A reality underscored on 28 May 2025 when a border dispute re-emerged between Thailand and Cambodia, marking a major escalation in the border dispute since late 2023 (Jones, 2025). The crisis began with a brief but deadly skirmish between Cambodian and Thai soldiers along the disputed border in the Chong Bok area of Northern Cambodia or Northeast Thailand (Yoon, 2025). This confrontation resulted in the death of at least one soldier, with some reports confirming two Cambodian fatalities. In the immediate aftermath, both sides blamed each other for initiating the hostilities (Teekah, 2025).
Following the deadly encounter, military reinforcements were rapidly deployed on both sides of the border. Cambodia escalated the dispute further by submitting a formal request to the International Court of Justice (ICJ) for adjudication (Strangio, 2025). In an attempt to defuse tensions, Acting Thai Prime Minister Phumtham Wechayachai and Cambodian Prime Minister Hun Manet convened for an in-person meeting at the official residence of Malaysian Prime Minister Anwar Ibrahim (Setboonsarng et al., 2025). However, even after a ceasefire was agreed upon, residual tension still lingers around the disputed area, and the international community is left questioning: how much longer will this issue persist, and is there a permanent solution for peace?
The Emerald Triangle Saga: From Colonial Boundaries to Border Clashes
The roots of the Thailand-Cambodia dispute can be traced back to the colonial era, influenced by the Franco-Siamese crisis in 1893. During this period, France expanded its control over Indochina (comprising Cambodia, Vietnam, and Laos) while pressuring the Kingdom of Siam (modern-day Thailand) to cede territories east of the Mekong River (John, 1998). Although Siam initially resisted, French gunboat diplomacy ultimately forced its compliance, resulting in the loss of most of Laos to France (Thomson, 1945). This concession enabled Siam to remain the only Southeast Asian country to avoid direct colonization, but at the cost of significant territorial losses (LePoer, 1987). The legacy of the treaty thus established the colonial-era boundaries that continue to be a source of contention today.
A second historical flashpoint centers on the Preah Vihear Temple, which is situated along the border on the Dângrêk Mountains. In 1962, the ICJ ruled that the temple belonged to Cambodia, relying on the Franco-Siamese treaty of 1907 and related maps (ICJ, n.d.). However, the ruling left the status of adjacent territory unresolved, creating a gray zone that became the focal point of competing claims (Ciorciari, 2009). The temple’s designation as a UNESCO World Heritage site in 2008 further internationalized the dispute but did little to clarify sovereignty over surrounding areas (Stalin, 2025). This unresolved status subsequently fueled tensions over both the Preah Vihear Temple area and the broader “Emerald Triangle,” where Cambodia, Thailand, and Laos converge. From 2008 to 2011, nationalist movements in both countries sparked repeated clashes that caused deaths, displacement, and civilian hardship (Al Jazeera, 2025). Although the Association of Southeast Asian Nation (ASEAN) and external powers, including the United States and China, intervened to mediate, their efforts only contained rather than resolved the dispute. By 2025, border clashes escalated severely with significant casualties and disruptions, prompting ceasefire agreements and multilateral efforts for peaceful resolution, although the core dispute remains unresolved (Naqsabandiyah, 2025).
Against this backdrop, the Thailand-Cambodia border conflict is best understood as being deeply rooted in colonial-era territorial rearrangements and further compounded by unresolved legal and nationalist disputes over strategically and culturally significant sites such as Preah Vihear Temple. Despite international legal rulings and diplomatic engagements, the complexities of border demarcation and issues of national pride continue to fuel tensions along the frontier.
Walking a Thin Line: The Thailand-Cambodia Border Today
Building on this persistent deadlock, the dispute eventually spilled beyond diplomatic forums into a critical phase marked by armed clashes and humanitarian suffering. Before negotiations began, at least 35 people had been killed and more than 270,000 displaced, urging the United States to interfere. Concerned that the escalating conflict threatened both regional stability and its own economic interests in Southeast Asia, President Donald Trump communicated with the leaders of both countries, warning that he would not pursue trade negotiations until a ceasefire was secured and advocating for the imposition of a 36% tariff (Ratcliffe, 2025). In response, the Thai and Cambodian foreign ministers swiftly agreed to a ceasefire as an outcome of their talk on August 4, 2025 in Malaysia, which was proposed as a neutral location to hold discussions regarding regional matters. Cambodian official Lim Menghour later remarked that Trump “showed positive development” regarding tariffs after the dialogue took place (Wongcha-um and McPherson, 2025). Around the same time, the UN Security Council held a private meeting to hear both nations’ positions, where Cambodia once again invoked the ICJ, while Thailand rejected the court’s jurisdiction and pressed for a bilateral resolution (Security Council Report, 2025).
Following this brief diplomatic breakthrough, the immediate and unconditional ceasefire agreement apparently did not last long, undermined by nationalist sentiments and deep mistrust between the two armies. Civilians in border areas continued to be evacuated to shelters, and reports of military equipment usage such as drones and rocket launchers are still coming in (Head, 2025). As a result, yet another dialogue was hosted in Malaysia, this time involving Cambodia and Thailand’s defence ministers. They agreed to allow observers from ASEAN to inspect disputed border areas and help ensure hostilities would not resume (Latiff, 2025). This interim observer team, which is tasked with observing, verifying, and reporting the border situation, consists of representatives from seven countries (Raksmey, 2025).
The damage caused by this conflict has deeply affected citizens of both countries, regardless of age or background. Thailand’s Basic Education Commission (OBEC) reported that 751 schools had to close down as a safety precaution. While most have reopened, OBEC is discussing ways to compensate for lost learning time (Parpart, 2025). UNICEF urged both countries to protect children and the critical services they depend on, emphasizing that schools must remain safe spaces for learning (Mishra, 2025). Meanwhile, concerns regarding the use of landmines arose after a Thai soldier was injured while patrolling near the border, sparking accusations between the neighboring countries (Al Jazeera, 2025). As of now, developments continue to unfold, showing both the volatility of the conflict and the fragility of peace in the region.
Beyond Territorial Boundaries: Hybrid Challenges in the Dispute
The Thailand-Cambodia border conflict demonstrates how traditional territorial disputes have evolved into hybrid confrontations spanning military, digital, economic, and diplomatic domains. Rooted in the ICJ’s 1962 ruling that awarded Preah Vihear Temple to Cambodia while leaving nearly 5 square kilometers of surrounding territory in legal ambiguity, the dispute intensified following the 2013 ICJ clarification, which granted Cambodia sovereignty over roughly half of the disputed 4.6 square kilometer promontory (Silobreaker Research Team, 2025). Since 2013, Thailand has shown consistent reluctance to accept ICJ jurisdiction, preferring bilateral negotiations through the Joint Border Commission mechanism.This created a legal standoff that escalated when Cambodia submitted four additional disputed areas to the ICJ in June 2025. This submission coincided with the 63rd anniversary of the original ruling and followed a fatal border incident (The Nation, 2025).
The July 24-28, 2025 armed conflict highlighted how territorial disputes now integrate conventional and non-conventional battlefields. Fighting that left 43 dead and displaced over 300.000 civilians was accompanied by cyber operations on an unprecedented scale. Thai officials reported over 500 million cyberattacks linked to multiple hacktivist groups, while Cambodia’s AnonSecKh group claimed responsibility for 73 separate digital assaults targeting government and military infrastructure (France24, 2025). Beyond cyberspace, the conflict was fueled by transnational criminal enterprises, particularly Cambodia’s extensive scam operation networks, which generate an estimated $12.5 billion annually and operate from Special Economic Zones near contested border areas. Thailand’s crackdown on these facilities prompted Cambodian military retaliation, underscoring how illicit economies have become intertwined with territorial sovereignty and national security (McPherson, 2025).
The digital front further extended into information warfare, destabilized political trust domestically and regionally. Coordinated disinformation campaigns, along with the leak of a confidential exchange between Hun Sen and Thai Prime Minister Paetongtarn Shinawatra, did not merely embarrass the leadership; they triggered a political crisis that led to the Prime Minister’s suspension and established dangerous precedents for diplomatic engagement in the digital age (Regan & Olarn, 2025).
ASEAN’s Trial by Fire: Limitation and Adaptation
ASEAN’s response revealed both its limitations and adaptive capacity. Initially paralyzed by its non-interference principles, the bloc was spurred into action when Malaysian Prime Minister, Anwar Ibrahim ultimately secured the July 28, 2025 ceasefire in Putrajaya, after President Trump’s ultimatum (Busbarat, 2025). ASEAN’s institutional evolution culminated in the creation of the ASEAN Interim Observer Team, led by Malaysian Brigadier General Dato’ Pahlawan Asri bin Shukor. Comprising representatives from seven member states, the team was tasked with monitoring the 840-kilometer border, marking the first comprehensive conflict-monitoring mechanism between ASEAN members. Building on this framework, the September 10, 2025 Special General Border Committee meeting produced five major agreements: the withdrawal of heavy weapons under international observation, joint mine-clearance operations, coordinated scam syndicate crackdowns with shared intelligence, bilateral management of disputed areas, and trade restriction consultations (The Nation, 2025).
These measures established crucial precedents for regional security governance, demonstrating ASEAN’s potential effectiveness when member states commit to leadership and coordinated action. At the same time, the conflict revealed the organization’s inherent limitations, particularly its reliance on external great-power influence to enforce compliance. Importantly, the crisis also highlighted ASEAN’s evolving capacity to confront hybrid threats, illustrating that territorial disputes are no longer isolated but increasingly intertwined with cyber warfare, transnational crime, and cross-border nationalist mobilization.
Conclusion
The Thailand–Cambodia border conflict underscores how historical grievances can be transformed by contemporary hybrid threats, posing significant challenges to regional peace and governance. What began as a dispute over maps and monuments has evolved to encompass armed clashes, cyber operations, criminal economies, and disinformation, testing not only bilateral relations but also ASEAN’s credibility as a security actor. The 2025 escalation revealed the costs of leaving colonial-era boundaries unresolved and the perils of neglecting mechanisms for legal and diplomatic settlement. At the same time, it demonstrated that determined regional leadership, supported by calibrated great-power engagement, can defuse crises and implement innovative monitoring tools such as the ASEAN Interim Observer Team. Achieving lasting peace will require both nations to separate nationalist politics from technical border management, cooperate against transnational crime, and respect agreed legal frameworks. The actions of Thailand and Cambodia in the coming months will determine whether the “Emerald Triangle” becomes a model for reconciliation or a cautionary tale for Southeast Asia.
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