In July 2025, a five-day intense border conflict between Thailand and Cambodia escalated tensions in the region to their highest level. The clashes resulted in the deaths of at least 38 people, the displacement of hundreds of thousands, and significant damage to schools and hospitals in the affected areas. A ceasefire was declared following diplomatic negotiations hosted by Malaysia, with pressure from both the United States and China playing a decisive role in facilitating the truce.
At the root of the conflict lie long-standing border disputes, stemming from maps inherited from the period of France’s colonial presence, as well as competing territorial claims around the Preah Vihear Temple. These disputes are widely regarded as one of the fundamental sources of historical and political instability in the region.
The border disputes between Thailand and Cambodia largely stem from maps drawn during the late 19th and early 20th centuries, as part of the legacy of France’s colonial presence in the region. While ruling Cambodia as a colony, France delineated borders in accordance with its own strategic interests. This process rendered the boundary lines, particularly in sacred and strategically important areas such as the Preah Vihear Temple and its surroundings, a matter of enduring contention.
Following France’s withdrawal from Indochina in 1954, Cambodia gained independence; however, the border issues remained unresolved. In 1962, the International Court of Justice (ICJ) ruled that the Preah Vihear Temple belonged to Cambodia. Nevertheless, the surrounding territory was not clearly demarcated, leading to occasional tensions in the ensuing decades. Regional conflicts such as the Cambodian Civil War and the Vietnam War during the 1970s further overshadowed the issue, leaving the core disputes largely unaddressed.
Throughout the 1990s and 2000s, Thailand and Cambodia experienced various border violations and small-scale clashes. Military movements and competing land claims around the Preah Vihear Temple sometimes led to increased tensions between the two countries. In 2011, the International Court of Justice (ICJ) allowed Thailand freedom of movement in the disputed border area, marking the start of a new phase. However, this decision did not fully resolve the tensions.
The July 2025 clashes are the most serious expression of this long and complicated history. Although regional and international actors have intervened to help control the situation, unresolved border disputes rooted in the colonial past still pose a threat to peace and stability in the region.
The Association of Southeast Asian Nations (ASEAN) has played a relatively limited role in managing the Thailand-Cambodia border conflict. Following its principle of non-interference, the bloc viewed the issue as one to be resolved bilaterally and avoided direct diplomatic intervention. While Malaysia, as the ASEAN chair at the time, acted as a mediator to facilitate the ceasefire, sources from Malaysia indicate that ASEAN as an institution did not take on an active mediation role.[i] Regional experts and academics have criticized ASEAN’s limited capacity in crisis management, emphasizing that existing mechanisms fail to inspire sufficient confidence and that structural reforms are urgently needed.
The recent border conflict between Thailand and Cambodia has severely tested ASEAN’s capacity in crisis management and reshaped regional security dynamics. In this context, the rhetoric of leaders is critically important for understanding the positions of the parties involved and the interventions of international actors.
Adhering to its principle of non-interference, ASEAN did not directly intervene in the conflict. However, Malaysia’s mediation efforts as the chair of ASEAN and joint statements by ASEAN Foreign Ministers reflect differing positions within the bloc. In particular, ASEAN’s structural limitations in crisis management and its pursuit of consensus have restricted its ability to respond effectively.
Thai Prime Minister Phumtham Wechayachai and Cambodian Prime Minister Hun Manet engaged in ceasefire talks. Thailand accused Cambodia of violating the ceasefire, while Cambodia reported detaining 20 Thai soldiers and the death of one. Former Prime Minister Hun Sen has played an active role in military strategy, highlighting the complexity of Cambodia’s leadership structure and Hun Sen’s continued influence.[ii]
China sought to play an active balancing role during the border conflict due to its close economic and diplomatic ties with both Thailand and Cambodia. At the ASEAN Summit held in Kuala Lumpur in early July, Chinese Foreign Minister Wang Yi held separate meetings with his Thai and Cambodian counterparts, expressing willingness to act as a “fair and objective” mediator. China’s strong economic relationships with both countries have enabled Beijing to maintain balance between the parties. Experts note that during a period when ASEAN’s crisis management stalled, China has emerged as a key actor capable of filling the gap in regional diplomacy.[iii]
ASEAN’s consensus-based decision-making structure, which prioritizes harmony, has limited its capacity to intervene effectively in the conflict. Institutionally, it lacks the mechanisms for urgent mediation or intelligence mobilization. This situation has exposed weaknesses in ASEAN’s regional security architecture. However, as a diplomatic platform, ASEAN holds potential to conduct talks through quiet diplomacy and special envoys.
Meanwhile, China has maintained official neutrality but, through strategic partnerships with both countries, has fulfilled roles of both mediator and balancer. In areas where ASEAN remained passive, China has emerged as an active and alternative diplomatic actor. During this process, the United States and Malaysia exerted diplomatic pressure, while China assumed a more complex yet effective role in mediating the peace process.
China has taken on a balancing role during the conflict, given its strong economic and diplomatic relations with both countries. During the ASEAN Summit, Chinese Foreign Minister Wang Yi indicated in separate meetings with his Thai and Cambodian counterparts that China is ready to serve as a “fair and objective” mediator. This statement reflects China’s strategic efforts to balance its interests in the region. China’s approach can be seen as part of a broader strategy to assert regional leadership and act as a stabilizing actor beyond ASEAN’s principle of non-interference. These statements are important for understanding ASEAN’s structural constraints in crisis management, the leadership dynamics between Thailand and Cambodia, and China’s regional policies.
The Thailand-Cambodia crisis has tested ASEAN’s crisis management capacity and revealed a lack of political consensus. This situation highlights ASEAN’s need for institutional reforms, particularly strengthening the Secretariat and the Troika mechanism. Meanwhile, China has sought to fill the diplomatic void created by ASEAN’s limited response. The key question remains whether ASEAN will use this crisis as a turning point for transformation or whether similar tensions will continue.
[i] “Ceasefire Takes Effect between Thailand, Cambodia after Five-Day Border Battle”, Reuters, July 28, 2025, https://www.reuters.com/world/china/ceasefire-takes-effect-between-thailand-cambodia-after-five-day-border-battle-2025-07-28/, (Date Accessed: 31.07.2025).
[ii] “Cambodia’s Hun Sen at Helm in Border Conflict with Thailand”, Reuters, July 31, 2025, https://www.reuters.com/world/asia-pacific/cambodias-hun-sen-helm-border-conflict-with-thailand-2025-07-31, (Date Accessed: 31.07.2025).
[iii] “China Offers Mediation in Thailand-Cambodia Border Dispute”, Thai Times, July 25, 2025, https://thaitimes.com/china-offers-mediation-in-thailand-cambodia-border-dispute, (Date Accessed: 31.07.2025).
