Thailand-Cambodia Conflict and Defense Diplomacy (2025–2026): Actors, Processes, and Conflict Management

Abstract

Keywords:

Introduction

Changes in the international security environment demonstrate that interstate conflicts do not always develop into large-scale conventional warfare. Territorial disputes may instead persist through border incidents, competing sovereignty claims, military deployments, and recurring episodes of armed confrontation. Such conflicts require mechanisms capable of managing security risks even when the underlying political or territorial dispute remains unresolved. In this context, states do not rely exclusively on coercive military capabilities but may also employ diplomatic instruments involving defense institutions and military actors to maintain communication, reduce uncertainty, and prevent localized incidents from escalating. Defense diplomacy is particularly relevant to this context because it utilizes defense institutions, personnel, and militaryto-military engagement as instruments of non-coercive interaction intended to support confidence-building and conflict prevention (Duangratana, 2019; Tokan et al., 2026; Var, 2017). The Thailand-Cambodia conflict provides an important case for examining this relationship between military-security dynamics and diplomacy. The conflict is rooted in unresolved border delimitation and demarcation issues and competing sovereignty claims, most prominently surrounding the Preah Vihear Temple area (Chachavalpongpun, 2013; Meyer, 2009). Although the International Court of Justice (ICJ) determined in 1962 that sovereignty over the Temple belonged to Cambodia and subsequently clarified the scope of the judgment in 2013, legal adjudication did not eliminate the broader border-security problem. The persistence of tensions illustrates that the legal determination of sovereignty does not necessarily remove the security concerns, military interactions, and political sensitivities surrounding an unresolved border. During the 2008–2011 period, these tensions escalated into military deployments and armed clashes, demonstrating how territorial disputes can become embedded in reciprocal security perceptions and military responses (Boonkob, 2023; Quyet, 2026; Wisaijorn, 2026). This pattern can be understood through the logic of the security dilemma. In an environment characterized by uncertainty and the absence of a supranational authority capable of guaranteeing state security, measures adopted by one state to protect its interests may be interpreted as threatening by the other. Military deployments, reinforcement of border positions, and other defensive measures can therefore generate reciprocal responses and increase the risk of escalation. The Thailand-Cambodia case illustrates how unresolved territorial claims can interact with national security considerations and domestic political pressures, making de-escalation difficult even when neither party necessarily seeks a prolonged military confrontation. The recurrence of tensions in 2025 further demonstrates the continuing relevance of mechanisms capable of managing military interaction and reducing the risk of renewed escalation. In particular, tensions along the ThailandCambodia border escalated into armed clashes on 24 July 2025, following a period of renewed military tensions between the two countries. The Thai Ministry of Foreign Affairs reported that heavy artillery was fired at Thai military positions on 24 July, while subsequent clashes continued along several border areas. The escalation prompted regional diplomatic engagement, including an ASEAN Foreign Ministers’ statement on 27 July 2025 calling for an immediate ceasefire and the resumption of dialogue. Against this background, defense diplomacy provides an analytical entry point for examining how states manage the security dimension of an interstate conflict. Existing studies of the Thailand-Cambodia dispute have predominantly examined the territorial and legal dimensions of the conflict, the role of ASEAN dispute-settlement mechanisms, Indonesia's mediation, and the broader political dynamics surrounding the Preah Vihear dispute (Chachavalpongpun, 2013; Farida, 2014; Jenne, 2017; Setyaningsih, 2018). Other studies have examined Indonesia's role in facilitating dialogue or ASEAN's role as a regional facilitator (Antuli et al., 2019; Indrawan & Pratomo, 2021; Luo, 2025; Setyowati & Nurulita, 2023). These studies are important for explaining the political and institutional dimensions of the dispute, but they provide less systematic attention to how defense actors and defenserelated mechanisms operate as instruments of conflict management when military tensions recur. This development is particularly important for understanding the role of defense diplomacy in the management of the Thailand-Cambodia conflict. Following the escalation, a ceasefire was agreed on 28 July 2025, accompanied by arrangements for direct military communication between regional commanders, the resumption of the General Border Committee (GBC), and ASEAN-coordinated observation of the ceasefire. These developments illustrate that the conflict was not addressed solely through political or diplomatic negotiations, but also through mechanisms involving military-to-military communication, bilateral defense institutions, and regional monitoring. However, the extent to which these mechanisms function as instruments of defense diplomacy and contribute to conflict management remains insufficiently examined. This gap becomes particularly important in light of the renewed Thailand-Cambodia confrontation in 2025. Accordingly, this study examines the actors, security issues, and processes through which defense diplomacy contributed to managing military tensions between Thailand and Cambodia during the 2025–2026 period. This study addresses this gap by conceptualizing defense diplomacy as a conflict-management and de-escalation instrument rather than as a mechanism that necessarily resolves the underlying territorial dispute. The study integrates a Neorealist perspective with the concept of defense diplomacy and the approaches of conflict management and conflict resolution. Neorealism provides the basis for understanding how an anarchic international environment, self-help behavior, and reciprocal threat perceptions can generate security dilemmas. Defense diplomacy is then examined as a noncoercive mechanism through which states attempt to manage these security dynamics through defense dialogue, military-tomilitary communication, confidence-building measures, ceasefire arrangements, and monitoring. Conflict management is used to assess the capacity of these mechanisms to contain violence and prevent escalation, while conflict resolution provides a framework for distinguishing short-term stabilization from efforts to address the underlying sources of conflict. Accordingly, this study addresses a specific gap in the existing literature on the Thailand-Cambodia conflict. Previous studies have predominantly examined the territorial and legal dimensions of the dispute, ASEAN’s role in dispute settlement, mediation, and broader political dynamics, while providing less systematic attention to how defense actors and defenserelated mechanisms manage recurring military tensions. Building on this gap, this study contributes a mechanism-based explanation of defense diplomacy under an unresolved territorial dispute. Specifically, the study demonstrates how security-dilemma pressures arising from uncertainty, military deployments, and reciprocal threat perceptions are addressed through defense-diplomatic practices, including military-tomilitary communication, bilateral defense coordination, ceasefire implementation, restraint, and monitoring, and how these practices are associated with observable processes of de-escalation across successive stages of the 2025–2026 Thailand-Cambodia conflict. Rather than treating defense diplomacy merely as defense cooperation or regional engagement, the study shows how it functions as a conflictmanagement mechanism that regulates military interaction without resolving the underlying territorial dispute. The analysis retains three interconnected dimensions actors, issues, and processes to trace this mechanism across the conflict. Actors refer to the state, defense, military, regional, and relevant international actors involved in managing the conflict. Issues refer to territorial claims, military deployments, troop movements, ceasefire implementation, and other security concerns that shape interaction. Processes refer to dialogue, negotiation, military communication, confidence-building, ceasefire implementation, and regional facilitation and monitoring. Based on this research gap and analytical focus, the study addresses the following research questions: 1. How do state, defense, military, regional, and international actors engage in defense diplomacy in managing the Thailand-Cambodia conflict? 2. What security issues are addressed through defense diplomacy, and how do these issues shape the interaction between Thailand and Cambodia? 3. Through what processes and mechanisms does defense diplomacy contribute to de-escalation and conflict management in the Thailand-Cambodia conflict? The study therefore aims to analyze how defense diplomacy operates as a conflict-management mechanism within the security-dilemma dynamics of the ThailandCambodia conflict. Specifically, it examines how actors, security issues, and defense-diplomatic processes interact to address uncertainty, military tensions, and risks of renewed escalation across successive stages of the 2025–2026 conflict. The central argument advanced in this study is that defense diplomacy provides institutional mechanisms through which security-dilemma pressures can be managed by maintaining military communication, reducing uncertainty, regulating military interaction, and supporting ceasefire implementation and monitoring. These mechanisms are associated with observable processes of de-escalation and temporary stabilization, but do not by themselves resolve the underlying territorial and political causes of the conflict, which remain subject to longer-term political and legal processes.

Theoretical Framework

Neorealism and Security Dilemma Neorealism provides the structural basis for understanding the security dynamics underlying the ThailandCambodia conflict. From a neorealist perspective, the international system is characterized by anarchy, in which states cannot depend entirely on a central authority to guarantee their security. States therefore tend to rely on their own capabilities and remain sensitive to developments that may affect their national security. Within this condition, actions undertaken by one state to strengthen its security may be interpreted as threatening by another state, even when such actions are primarily defensive in nature (Bercovitch & Jackson, 2001; Laksmana, 2012). This condition can generate a security dilemma. An increase in military presence, reinforcement of border positions, or other defense-related measures may be perceived by the opposing state as an indication of hostile intentions. The opposing state may consequently respond by strengthening its own military posture, producing reciprocal security responses and increasing the possibility of escalation. In the Thailand-Cambodia conflict, the unresolved nature of the border dispute contributes to this condition because military activities around contested areas cannot be separated from broader questions of sovereignty, territorial security, and national interests (Tan & Singh, 2012; Tang, 2009). The neorealist perspective is therefore used in this study to explain the structural conditions that contribute to the emergence and persistence of security tensions between Thailand and Cambodia. It does not assume that military confrontation is inevitable, but rather emphasizes the uncertainty and reciprocal threat perceptions that can make escalation more likely. This perspective provides the foundation for examining why mechanisms capable of reducing uncertainty and regulating military interaction become important in situations of heightened tension. Defense Diplomacy Defense diplomacy is the central concept used in this study to examine how security tensions between Thailand and Cambodia are managed through defense-related interaction. Defense diplomacy refers to the use of defense institutions, military personnel, and military communication channels to pursue diplomatic objectives through non-coercive engagement. Its activities may include defense dialogue, military-to-military communication, confidence-building measures, and other forms of interaction intended to reduce misunderstanding and manage tensions between states (Cottey & Forster, 2004a). The relevance of defense diplomacy in the ThailandCambodia case lies in the fact that the conflict is not exclusively a political or legal dispute. Military activities along the border can directly influence the escalation of tensions, making communication between defense and military institutions an important component of conflict management. Defense diplomacy can provide channels through which military actors communicate their positions, clarify developments on the ground, discuss security concerns, and support arrangements intended to prevent further escalation (Cottey & Forster, 2004b). In this study, defense diplomacy is distinguished from broader political diplomacy. Diplomatic activities conducted by foreign ministries or political leaders are not automatically categorized as defense diplomacy. The analysis focuses specifically on interactions in which defense institutions, military actors, military communication, or defense-related arrangements play a substantive role. This distinction is important because the study seeks to examine how securityrelated interaction contributes to the management of military tensions rather than assessing diplomacy in general. Conflict Management and Conflict Resolution The concept of conflict management is used to examine whether defense diplomacy can help control the intensity and consequences of conflict without necessarily resolving its underlying causes. Conflict management focuses on limiting violence, preventing escalation, maintaining communication, and creating conditions in which conflicting parties can continue to interact despite unresolved disagreements (Badache et al., 2022). In the context of the Thailand-Cambodia conflict, such mechanisms are particularly relevant because the reduction of military confrontation does not necessarily mean that the territorial dispute has been settled. Defense dialogue, military communication, confidencebuilding measures, ceasefire arrangements, and monitoring mechanisms can therefore be understood as conflictmanagement instruments when they contribute to controlling military tensions. Their importance lies not only in their formal existence but also in whether they provide practical channels for communication and help prevent misunderstandings or incidents from developing into broader confrontation (Cheyre, 2013; Drab, 2018). Conflict resolution represents a broader and longer-term objective. While conflict management seeks to control the manifestations of conflict, conflict resolution concerns efforts to address the underlying incompatibilities that sustain the dispute. In the Thailand-Cambodia case, this distinction is particularly important because territorial claims and questions concerning the border cannot necessarily be resolved through military-to-military engagement alone. Defense diplomacy may contribute to a more stable environment for negotiation, but it should not automatically be interpreted as resolving the fundamental territorial dispute. Integrated Theoretical Perspective The theoretical perspectives used in this study are therefore understood as complementary rather than as separate theoretical approaches. Neorealism explains the structural security environment in which Thailand and Cambodia interact and helps explain how uncertainty and reciprocal threat perceptions can contribute to military tension. Defense diplomacy provides the analytical lens for examining the defense and military mechanisms employed by the actors in responding to those tensions. Conflict management is then used to assess how these mechanisms contribute to controlling escalation and maintaining communication, while conflict resolution provides a basis for determining whether such management efforts extend to addressing the underlying causes of the dispute. This integrated perspective is particularly useful for analyzing the Thailand-Cambodia conflict because it avoids equating the cessation of military confrontation with the resolution of the conflict itself. A reduction in violence, continued military communication, or the implementation of a ceasefire may indicate that conflict-management mechanisms are functioning, but these developments do not necessarily demonstrate that the territorial dispute has been permanently resolved. Accordingly, this study examines defense diplomacy primarily as an instrument of conflict management and deescalation. Its effectiveness is considered in terms of observable processes, including the continuity of communication between defense actors, the management of military incidents, the implementation of ceasefire arrangements, and efforts to reduce the possibility of renewed escalation. The underlying territorial dispute remains an issue that requires longer-term political and legal processes beyond the immediate scope of defense diplomacy. The framework also guides the empirical analysis through three interconnected dimensions: actors, issues, and processes. The actor dimension examines the roles of Thailand and Cambodia as the principal parties as well as the involvement of ASEAN and other relevant actors. The issue dimension focuses on the security concerns that shape military and diplomatic interaction, including territorial claims, military deployments, border incidents, and ceasefire arrangements. The process dimension examines how defense diplomacy is practiced through dialogue, military communication, confidence-building, ceasefire implementation, and related mechanisms of conflict management. This structure allows the study to connect the theoretical explanation of security tensions with the empirical examination of how those tensions are managed.

Methods

Research Design and Case Selection This study employs a qualitative single-case study design to examine defense diplomacy in the Thailand-Cambodia conflict. A case study is appropriate when a contemporary phenomenon is investigated in depth within its real-life context, particularly when the boundaries between the phenomenon and its context are not clearly separable (Yin, 2018). The approach also enables the analysis of the complexity and particularity of a bounded case through multiple sources of evidence (Rahmadhani et al., 2025). The Thailand-Cambodia conflict is treated as a bounded case because the analysis focuses specifically on the interaction between the two states in relation to borderrelated military tensions and the defense-diplomatic mechanisms employed to manage those tensions. The case is bounded spatially by the Thailand-Cambodia border and the bilateral, regional, and international mechanisms directly associated with the conflict. Temporally, the primary analytical boundary covers the renewed escalation and subsequent conflict-management processes during 2025–2026, while developments from 2008–2011 are used only to establish the historical context of the dispute. The selection of a single case is justified by its analytical relevance to the research questions. Rather than seeking statistical representativeness, the study uses the case to obtain an in-depth understanding of how defense diplomacy operates within a contemporary interstate security crisis. The case is particularly informative because it combines a persistent territorial dispute with renewed military tensions, direct military interaction, bilateral defense mechanisms, and regional diplomatic involvement. These characteristics allow the study to examine, within one bounded setting, (1) the actors involved in defense diplomacy, (2) the security issues addressed through these mechanisms, and (3) the processes through which defense diplomacy contributes to de-escalation and conflict management. In this respect, the case functions as an analytically informative single case rather than as a statistically representative sample. The longitudinal dimension of the case also permits examination of defense-diplomatic processes across different stages of the 2025–2026 escalation and subsequent ceasefire and conflict-management efforts. This design is consistent with the use of single-case research to investigate a case intensively when its characteristics provide particular analytical value for understanding a phenomenon of theoretical or empirical interest (Yin, 2018). Data Sources and Document Selection The study relied primarily on publicly accessible documentary sources relevant to the Thailand-Cambodia border conflict and the use of defense diplomacy during the 2025–2026 escalation and de-escalation period. The documentary corpus was purposively constructed to address the three research questions concerning the actors, security issues, and processes associated with defense diplomacy. Documents were selected based on four criteria: direct relevance to the research questions, institutional or scholarly credibility, sufficient information concerning the actors and mechanisms under examination, and clear temporal or contextual relevance to the case. Documents were treated as data sources, while the primary unit of analysis was the defense-diplomacy interaction, mechanism, or conflictmanagement event documented in the selected sources. The primary empirical corpus comprised 12 official documents issued by ASEAN, the governments of Thailand and Cambodia, and bilateral Thailand-Cambodia mechanisms during the 2025–2026 conflict-management process. The documents were selected to capture the major stages of escalation, ceasefire, bilateral coordination, monitoring, and subsequent implementation. The corpus consisted of: (1) the ASEAN Foreign Ministers’ Statement on the Thailand-Cambodia Border Dispute (27 July 2025); (2) the Thai Ministry of Foreign Affairs briefing on the outcome of the Special Meeting (28 July 2025); (3) the ASEAN Foreign Ministers’ Statement on the Outcome of the Special Meeting (31 July 2025); (4) the Extraordinary General Border Committee (GBC) Joint Press Statement (7 August 2025); (5) the Special GBC Joint Press Statement (10 September 2025); (6) the Second Special GBC Joint Press Statement (23 October 2025); (7) the Kuala Lumpur Joint Declaration (26 October 2025); (8) the Third Special GBC Joint Statement (27 December 2025); (9) the ASEAN Chair’s Statement on the Outcomes of the Third GBC Meeting (29 December 2025); (10) the Thai Ministry of Foreign Affairs statement on the Third GBC Meeting (27 December 2025); (11) the Thai Ministry of Foreign Affairs briefing to the diplomatic corps on the implementation of the December ceasefire (30 December 2025); and (12) the Cambodian statement concerning implementation of the ceasefire in 2026. The search for documentary evidence was conducted through official institutional repositories, particularly the websites of ASEAN, the Ministry of Foreign Affairs of Thailand, and the Royal Government of Cambodia. Academic databases and established international media archives were also consulted to identify relevant contextual and chronological materials. Search terms were derived from the research questions and theoretical framework and included combinations of Thailand-Cambodia conflict, ThailandCambodia border, Preah Vihear, border conflict, defense diplomacy, military communication, ceasefire, confidencebuilding measures, ASEAN, monitoring, and conflict management. The primary analytical period was 2025–2026, while documents published before 2025 were retained only when necessary to establish historical or theoretical context. The selection process consisted of identification, screening, and inclusion. Potentially relevant materials were first identified through the institutional repositories and databases described above. Materials were then screened for relevance to the Thailand-Cambodia case and the study's analytical framework. Documents were excluded when they were duplicates, unrelated to the Thailand-Cambodia case, lacked sufficient substantive information, or addressed broader regional security issues without a direct connection to the case. Where different accounts concerning military incidents or the responsibilities of either party were identified, information was cross-checked against independent official and secondary sources, and contested claims were reported cautiously. For the empirical analysis, official documents were given priority over secondary sources whenever primary documentation was available. In particular, official ASEAN, Thai, and Cambodian documents were used as the principal evidence for claims concerning ceasefire arrangements, military-to-military communication, troop positions, bilateral defense mechanisms, the GBC, ASEAN facilitation, monitoring, and implementation arrangements. Academic publications were used primarily to establish the theoretical and conceptual framework and to contextualize the findings, while credible international media reports were used only as supplementary sources for event chronology and crosschecking. Each selected document was recorded according to its issuing institution, publication date, document type, relevant event or security issue, actors involved, and analytical relevance. The date of publication was distinguished from the date of the event described in the document to avoid attributing later interpretations to earlier events. The documents were subsequently coded according to three dimensions: actors, issues, and processes. Table 1. Documentary Corpus Used for the Empirical Analysis Data Collection Procedure Data collection followed a structured documentary research procedure. Relevant materials were identified through searches of official institutional websites, academic databases, and established international media archives. Search terms were developed from the research questions and theoretical framework and included combinations of terms related to the Thailand-Cambodia conflict, Preah Vihear, border conflict, defense diplomacy, military communication, ceasefire, confidence-building measures, ASEAN, monitoring, and conflict management. The collection process was organized around the temporal boundary of the study. Documents concerning the 2025 escalation and subsequent developments in 2026 were prioritized, while earlier documents were retained only when they were necessary to establish historical continuity or explain the development of relevant conflict-management mechanisms. Each selected document was recorded according to its source, publication date, issuing institution, type of document, relevant event or issue, actors involved, and analytical relevance. Particular attention was given to the date of the event described in a document and the date of publication, since these are not necessarily identical. This procedure was used to reduce the risk of attributing later interpretations to events that occurred earlier in the conflict. Analytical Framework and Coding Procedure The analysis was guided by the integrated theoretical framework developed in this study. Neorealism and the security dilemma were used to examine the security environment and reciprocal threat perceptions underlying military interaction. Defense diplomacy was used to identify and examine defenserelated mechanisms through which actors communicated, coordinated, or managed military and security issues (Agastia & Perwita, 2017). Conflict management was used to assess mechanisms directed toward containing violence, preventing escalation, maintaining communication, and managing military incidents. Conflict resolution was used

as a broader analyticaldistinction to determine whether such mechanisms addressed the underlying territorial dispute or primarily managed its security consequences. A structured coding procedure was developed before the interpretation of the empirical findings. The coding focused on three principal dimensions: actors, issues, and processes. The actor category identifies the state, defense, military, regional, and international actors involved in a documented defense-diplomacy process. Particular attention is given to Thailand and Cambodia as the primary parties, their defense and military institutions, and ASEAN or other external actors when their involvement has a direct connection to the management of the conflict. The issue category identifies the security concerns addressed by the relevant interaction. These include territorial and border-security concerns, military deployments, border incidents, troop positions, cessation of hostilities, ceasefire implementation, monitoring, and other security concerns directly documented in the sources. The process category identifies the mechanism through which defense diplomacy was conducted. The coding includes defense dialogue, military-to-military communication, negotiation, information exchange, confidence-building measures, ceasefire arrangements, monitoring or verification, and regional facilitation. To distinguish defense diplomacy from broader political diplomacy, an activity was classified as defense diplomacy when it involved defense institutions, military actors, militaryto-military communication, defense-related arrangements, or the direct management of military and security activities. Meetings involving foreign ministers or the ASEAN Chair were not automatically classified as defense diplomacy. Such activities were included only when they had a documented connection to defense-related processes, such as ceasefire arrangements, military monitoring, troop positions, or the implementation of security agreements. This criterion was applied to avoid extending the concept of defense diplomacy to all forms of political diplomacy. The coding also distinguished conflict management from conflict resolution. Evidence was coded as conflict management when a mechanism primarily served to contain violence, reduce escalation risks, maintain communication, regulate military interaction, or support ceasefire implementation. Evidence was considered relevant to conflict resolution only when it addressed the underlying territorial, sovereignty, or boundary issues that sustain the conflict. A ceasefire or reduction in violence was therefore not treated as evidence that the underlying conflict had been resolved. The coding process proceeded from individual documentary evidence to thematic categories and then to theoretical interpretation. For example, a documented military communication mechanism was first coded according to the actors involved and the security issue addressed. It was then classified according to its function, such as communication maintenance, incident management, or confidence-building. Finally, its significance was interpreted in relation to the security dilemma and conflict-management framework. Documentary Analysis and Triangulation The documentary materials were analyzed using the interactive qualitative analysis approach of Miles, Huberman, and Saldaña (2014), involving data condensation, data display, and conclusion drawing and verification. During data condensation, relevant passages were extracted and organized according to the predefined coding categories. Data were subsequently displayed through thematic summaries, event chronologies, and analytical tables to facilitate comparison across actors, mechanisms, and stages of the conflict. Triangulation was conducted by comparing evidence across different types of sources rather than merely counting the number of sources supporting a particular claim. Official government and institutional documents were prioritized for statements concerning formal policy positions, agreements, and institutional actions. Academic literature was used to provide conceptual and analytical context, while credible media reports were used primarily to supplement event chronology and identify developments requiring verification. Where sources presented conflicting accounts, the analysis considered the institutional position, proximity to the event, publication date, and availability of independent corroboration before determining how the evidence should be interpreted. Particular caution was applied to contested claims concerning military actions, responsibility for incidents, and strategic intentions. The study does not infer an actor's intention solely from its reported behavior. Interpretations concerning intentions are therefore presented cautiously unless they are explicitly documented in authoritative sources or supported by multiple independent sources. Trustworthiness of the Analysis Several procedures were applied to enhance the trustworthiness of the findings. First, an audit trail was maintained through the recording of source information, publication dates, relevant events, coding categories, and the relationship between documentary evidence and analytical conclusions. Second, source triangulation was used to reduce dependence on any single institutional or media narrative (Aprila & Dwiharyadi, 2026). Third, contradictory or disconfirming evidence was retained during the analytical process rather than being excluded simply because it did not support the emerging interpretation. Fourth, the analysis distinguished empirical evidence from theoretical interpretation. Findings were first established from documentary evidence and chronology, after which the evidence was interpreted using the theoretical framework. This procedure was intended to prevent theoretical concepts such as the security dilemma, confidence-building, or conflict management from being imposed on the case without documentary support. The analysis was considered sufficiently complete when the selected documents had been systematically coded according to the research questions and additional documents no longer produced substantively new categories of actors, issues, or defense-diplomacy mechanisms relevant to the case. Because the study is based on public documentary evidence, this criterion refers to analytical completeness within the defined corpus rather than statistical saturation. Research Ethics The study uses publicly available documentary, institutional, academic, and media sources and does not involve interviews, surveys, or direct interaction with human participants. Consequently, the study does not involve the collection of personal or confidential participant data. Nevertheless, ethical care was maintained in attributing claims to their original sources, distinguishing verified information from contested narratives, and avoiding unsupported attribution of intentions to the parties involved. Documentary materials were used for analytical purposes with appropriate source attribution, and interpretations were presented in a manner that recognizes the contested nature of the conflict.

Result and Discussion

Actors Involved in Defense Diplomacy The analysis identifies Thailand and Cambodia as the principal actors in the management of the conflict because both states possess direct authority over political, defense, and military decisions concerning the border. At the bilateral level, the relevant actors include government representatives, ministries of defense, military commanders, and military institutions responsible for communication and implementation of security arrangements. The documentary evidence indicates that defense-related interaction became particularly important during periods of heightened tension, when political decisions concerning the cessation of hostilities had to be translated into arrangements applicable to military activities along the border (Association of Southeast Asian Nations, 2025a). The analysis also identifies ASEAN as a regional actor that became involved in the conflict-management process. ASEAN's role was exercised primarily through its Chair, ministerial-level diplomatic engagement, and mechanisms associated with ceasefire monitoring. The July 2025 ASEAN Foreign Ministers' Statement called on Thailand and Cambodia to exercise maximum restraint, immediately cease hostilities, and return to negotiations. ASEAN also expressed support for the efforts of the ASEAN Chair to facilitate the process (Association of Southeast Asian Nations, 2025b). These actions demonstrate ASEAN's involvement in facilitating communication and de-escalation between the two parties. At the operational level, military actors played a distinct role from political and diplomatic actors. Following the July 2025 ceasefire, communication between military commanders and defense-related institutions was used to address implementation issues and maintain contact between the parties. The subsequent development of bilateral mechanisms indicates that military actors were not merely implementing political decisions but also participated directly in managing security conditions along the border (Association of Southeast Asian Nations, 2025c). The ASEAN Observer Team (AOT) represents another relevant actor in the conflict-management process. Its involvement was associated with the implementation and verification of ceasefire arrangements. The role of the AOT was therefore different from that of Thailand and Cambodia: while the two states remained the principal parties to the conflict, ASEAN-related mechanisms provided an additional regional channel for monitoring and supporting implementation (Association of Southeast Asian Nations, 2026). Overall, the findings show a multi-level configuration of actors. Thailand and Cambodia remained the principal parties, their defense and military institutions were directly involved in managing security interactions, while ASEAN provided a regional facilitation and monitoring function. The evidence does not indicate that all ASEAN or international diplomatic activities constituted defense diplomacy; activities involving military institutions, defense communication, ceasefire implementation, and security-related coordination were more directly connected to the defense-diplomacy dimension. Security Issues Addressed Through Defense Diplomacy The analysis identifies several recurring security issues addressed through defense-related interactions between Thailand and Cambodia. The most prominent issues were ceasefire implementation, military activities along the border, troop positions and movements, military incidents, communication between commanders, and mechanisms for monitoring compliance with agreed arrangements (Association of Southeast Asian Nations, 2026). The ceasefire became a central issue following the armed clashes in 2025. The subsequent diplomatic and military processes did not focus only on declaring a cessation of hostilities but also on determining how the cessation could be maintained in practice. This included arrangements concerning troop positions, communication between relevant authorities, and mechanisms for addressing potential violations or incidents (Ministry of Foreign Affairs of Thailand, 2025c). Another important issue was the management of military activities and the risk of renewed confrontation. The documentary evidence indicates that military-to-military communication was maintained as part of the post-ceasefire process. Such communication was relevant to situations in which activities along the border could potentially be interpreted as hostile or could generate further tension. The continued involvement of military actors therefore formed part of the practical management of the security environment (Ministry of Foreign Affairs of Thailand, 2025d). Monitoring and verification also emerged as important security issues. ASEAN-supported monitoring mechanisms were introduced in connection with the implementation of ceasefire arrangements. The inclusion of monitoring mechanisms provided an additional institutional channel through which information concerning compliance could be communicated and assessed (Ministry of Foreign Affairs of Thailand, 2025a). The findings also show that several measures commonly associated with confidence-building were incorporated into the broader de-escalation process. However, the analysis does not treat the ceasefire itself as automatically constituting a confidence-building measure. Rather, measures such as maintaining troop positions, continuing military communication, establishing monitoring arrangements, and regulating military activities provide the more specific evidence of confidence-building and risk-reduction practices (Ministry of Foreign Affairs of Thailand, 2025b). At the same time, the security issues addressed through defense diplomacy remained distinct from the underlying territorial dispute. The documentary evidence shows continued attention to immediate security risks and military interaction, whereas questions concerning border delimitation, demarcation, and competing territorial claims remained part of the broader political and legal dispute. Processes and Mechanisms of De-escalation The findings reveal a sequential development of conflictmanagement processes during the 2025 escalation and subsequent de-escalation period. Rather than relying on a single diplomatic mechanism, Thailand, Cambodia, and ASEAN used several interconnected processes involving ceasefire arrangements, direct communication, bilateral coordination, and regional monitoring (Royal Government of Cambodia, 2025b). The first major process was the establishment of a ceasefire following the armed clashes in July 2025. The ceasefire provided an immediate mechanism for stopping hostilities and creating conditions for further communication. However, the subsequent diplomatic process demonstrates that cessation of hostilities was not sufficient by itself to manage the security situation. Additional arrangements were required to address military activities and maintain communication between the parties (Royal Government of Cambodia, 2025a). The second process involved the restoration and continuation of direct communication between defense and military actors. Following the ceasefire, military commanders and relevant authorities continued to communicate concerning developments along the border. This created a channel through which security-related issues could be addressed without relying exclusively on higher-level political negotiations. The third process involved the institutionalization of bilateral mechanisms. The General Border Committee (GBC) and other bilateral mechanisms provided formal settings for addressing border and security issues. The documentary

The fourth process involved greater regional involvement through ASEAN. ASEAN's role developed from diplomatic facilitation toward support for monitoring and verification mechanisms. The ASEAN Foreign Ministers' engagement in July 2025 was followed by further regional involvement in subsequent ceasefire-related processes. This provided a regional framework within which the bilateral parties could continue their engagement while retaining primary responsibility for implementation (Association of Southeast Asian Nations, 2025b). A further development occurred on 27 December 2025, when Thailand and Cambodia agreed to another ceasefire arrangement that included cessation of hostilities, maintenance of troop positions, and continued coordination and monitoring mechanisms. The subsequent arrangements therefore extended the focus from simply stopping fighting toward regulating military behavior and monitoring the implementation of the ceasefire (Ministry of Foreign Affairs of Thailand, 2025b). Taken together, the documented process can be summarized as a movement from cessation of hostilities toward communication, coordination, and monitoring. The sequence demonstrates that de-escalation involved several mutually connected mechanisms rather than a single diplomatic intervention. Documented Mechanisms of Defense Diplomacy The findings identify several mechanisms through which defense diplomacy was practiced during the period under examination. These mechanisms are summarized in Table 2. To ensure documentary traceability, the table distinguishes between provisions directly documented in official records and the authors’ analytical interpretation of their conflictmanagement functions. The mechanisms identified in Table 2 show that defense diplomacy operated through both bilateral and regional channels. Bilateral mechanisms remained central because Thailand and Cambodia were the parties directly responsible for military activities and ceasefire implementation. These mechanisms included ceasefire arrangements, military-tomilitary communication, the General Border Committee (GBC), the Regional Border Committee (RBC), troop-position arrangements, and other measures designed to regulate military interaction. Regional mechanisms complemented these bilateral processes through ASEAN-supported facilitation, observation, and verification arrangements. The findings further indicate that these mechanisms performed distinct but interconnected functions. Ceasefire arrangements addressed the immediate cessation of hostilities, while restrictions on troop movements and military reinforcement sought to stabilize the military situation following the ceasefire. Military-to-military communication Taken together, these mechanisms demonstrate that defense diplomacy in the Thailand-Cambodia case did not operate through a single instrument. Rather, it developed through a combination of bilateral defense mechanisms and complementary regional arrangements that addressed different stages and operational requirements of de-escalation and conflict management. The distinction in Table 2 between directly documented provisions and analytical interpretation also clarifies which elements are explicitly contained in official records and which represent the authors’ assessment of their defense-diplomatic functions. Development of the Conflict-Management Process The documentary evidence indicates that the defensediplomacy process developed through several stages during the period examined. The initial stage was characterized by armed confrontation and the urgent need to stop hostilities. The second stage involved the establishment of communication between the parties following the ceasefire. The third stage involved the use of bilateral mechanisms to manage military and border-related issues. The fourth stage involved the expansion of regional involvement through ASEANsupported monitoring and verification. This development is particularly visible in the sequence of arrangements established during 2025. The July ceasefire created the initial basis for de-escalation, while subsequent bilateral and regional mechanisms addressed the practical challenges of maintaining the cessation of hostilities. The 27 December 2025 arrangements further formalized measures concerning troop positions, military conduct, and monitoring (Ministry of Foreign Affairs of Thailand, 2025b). The evidence therefore shows that the conflictmanagement process moved beyond an immediate cessation of fighting toward mechanisms intended to regulate interactions between the parties. Nevertheless, the documentary record also indicates that these mechanisms were directed primarily toward managing military and security consequences of the dispute. The underlying territorial and border-related disagreements remained subject to longer-term political and diplomatic processes. Defense Diplomacy as an Instrument of Conflict Management The findings indicate that defense diplomacy in the Thailand-Cambodia conflict primarily operates as an instrument of conflict management rather than conflict resolution. The evidence shows that defense-related interaction was directed mainly toward controlling the security consequences of the conflict, particularly through military-to-

military communication, bilateral defense coordination, ceasefire implementation, regulation of troop positions, and monitoring arrangements. These mechanisms did not eliminate the underlying territorial disagreement, but they provided channels through which Thailand and Cambodia could manage military tensions and reduce the possibility of renewed armed confrontation. The documentary evidence indicates that the defensediplomacy process developed through several stages during the period examined. The initial stage was characterized by the establishment of an immediate ceasefire and the reactivation of direct military and bilateral communication. Following the 28 July 2025 Special Meeting, Thailand and Cambodia agreed to an immediate ceasefire, informal meetings between regional military commanders, the subsequent convening of the General Border Committee (GBC), and the resumption of direct discussions among senior political and defense officials. Malaysia, as ASEAN Chair, was also designated to coordinate and observe the ceasefire. The second stage involved the institutionalization of military communication and ceasefire implementation through bilateral defense mechanisms. At the Extraordinary GBC Meeting on 7 August 2025, the two sides agreed to maintain their existing troop deployments, refrain from troop movements and reinforcement, avoid provocative actions, and establish regular communication among army areas, military regions, and border units. The agreement also provided for direct lines of communication between the Ministers of Defence and Chiefs of Defense Forces. The respective Regional Border Committees (RBCs) were assigned to implement the ceasefire and report to the GBC, while an Interim Observer Team (IOT) was established pending the formation of the ASEAN Observer Team. The third stage involved further institutionalization of deescalation and confidence-building measures. At the Special GBC Meeting on 10 September 2025, both sides reaffirmed the importance of regular communication among military regions, army areas, and border units and agreed to advance measures for the removal of heavy and destructive weapons under observation and verification by the ASEAN Observer Team. The meeting also recognized the continuing role of the IOT pending establishment of the AOT and explicitly linked these measures to de-escalation and the restoration of confidence. The process subsequently developed into more formalized arrangements concerning monitoring and military de-escalation. The 23 October 2025 Special GBC Meeting endorsed an Action Plan for the Removal of Heavy and Destructive Weapons, the Terms of Reference for the ASEAN Observer Team, and Standard Operating Procedures for the Joint Coordinating Task Force on Humanitarian Demining. The Kuala Lumpur Joint Declaration of 26 October 2025 further formalized the AOT and committed both sides to military deescalation, removal of heavy and destructive weapons, confidence-building measures, and humanitarian demining. The fourth stage involved the implementation and monitoring of the December 2025 ceasefire arrangements. The Third Special GBC Meeting of 27 December 2025 reaffirmed the implementation of the existing ceasefire and bilateral mechanisms, while the subsequent arrangements provided for a ceasefire effective from 12:00 on 27 December 2025 and monitoring and observation for 72 hours. The Thai Ministry of Foreign Affairs also documented measures concerning the maintenance of troop positions, restrictions on troop movement and reinforcement, humanitarian demining, and direct communication between defense ministers and military commanders. The evidence therefore shows that the conflictmanagement process moved beyond an immediate cessation of fighting toward increasingly institutionalized mechanisms for regulating military interaction. These mechanisms included direct military communication, bilateral GBC and RBC processes, observer arrangements, restrictions on troop movements, weapons-removal measures, and humanitarian demining. At the same time, the documentary record indicates that these mechanisms were directed primarily toward managing the military and security consequences of the dispute rather than resolving the underlying territorial disagreement. This finding is consistent with the conceptualization of defense diplomacy as the use of defense institutions, personnel, and military channels for non-coercive engagement, confidence building, and conflict prevention (Cottey & Forster, 2004a; Tan & Singh, 2012). In the Thailand-Cambodia case, this function becomes particularly visible when political disagreement translates into military risks at the border. Political negotiations may establish a decision to stop hostilities, while defense institutions provide channels through which such decisions can be communicated and implemented in operational settings (Hyma et al., 2026; Vazquez et al., 2024). The findings therefore suggest that defense diplomacy functions as an important intermediary between political decisions and military behavior. The distinction between conflict management and conflict resolution is important in interpreting this finding. Conflict management refers to efforts to contain or regulate the intensity and consequences of conflict without necessarily eliminating the underlying incompatibilities between the parties. It may involve negotiation, mediation, communication, and other mechanisms designed to prevent escalation and manage interactions between conflicting parties (Bercovitch & Jackson, 2001). Conflict resolution, by contrast, concerns efforts to address the underlying sources and incompatibilities of conflict and to create conditions for a more sustainable settlement. This distinction is particularly relevant to the Thailand-Cambodia case because mechanisms that reduce military confrontation do not necessarily resolve the underlying territorial disagreement. In the case examined, the documented mechanisms primarily correspond to conflict management. Ceasefire arrangements, military-to-military communication, bilateral defense coordination, restrictions on troop movements, and monitoring mechanisms were directed toward containing military tensions and reducing the risk of renewed confrontation. These mechanisms contributed to de-escalation and the regulation of military interaction, but the documentary evidence does not indicate that they produced a final settlement of the underlying territorial dispute. Defense diplomacy may therefore contribute to creating a more stable environment for longer-term political and diplomatic negotiations, but it should not automatically be interpreted as resolving the fundamental dispute. The findings therefore provide a more precise understanding of the role of defense diplomacy. Its effectiveness should not be evaluated by whether it produces a final territorial settlement. Rather, its effectiveness is more appropriately assessed through process-oriented indicators, including the continuity of defense communication, implementation of ceasefire arrangements, containment of military incidents, operation of monitoring mechanisms, and the continuation of observable de-escalation. In this sense, defense diplomacy creates the conditions necessary for conflict parties to move from direct confrontation toward controlled interaction. This interpretation also responds to the first and third research questions. The principal actors were not only political leaders but also defense ministries, military commanders, and military institutions that translated political agreements into security-related practices. The process therefore demonstrates that defense diplomacy is not an alternative to political diplomacy but operates alongside it, particularly when political decisions have direct consequences for military activities at the border. Defense Diplomacy and the Security Dilemma The findings can also be interpreted through the logic of the security dilemma. From a neorealist perspective, states operate in an international system characterized by anarchy and uncertainty, making them responsible for their own security. Under these conditions, defensive measures taken by one state may be interpreted as threatening by another, encouraging reciprocal responses (Aji, 2015). This dynamic provides an important explanation for why military activities surrounding a territorial dispute can escalate even when neither side necessarily seeks unlimited confrontation. The Thailand-Cambodia case illustrates this problem at the operational level. Military deployments, troop positions, border activities, and reports of military incidents create uncertainty regarding the intentions and future actions of the other party. When such uncertainty is not addressed through communication, defensive behavior can be interpreted as preparation for offensive action. The resulting interaction may reinforce a cycle in which each side responds to the other's security measures, thereby increasing the possibility of escalation. Defense diplomacy provides a mechanism for interrupting this cycle without requiring either state to abandon its security interests. Military-to-military communication, commanderlevel contact, bilateral defense coordination, and monitoring arrangements increase opportunities for information exchange and clarification. These mechanisms do not remove the underlying strategic competition, but they can reduce uncertainty concerning military behavior. This interpretation is consistent with the argument that defense diplomacy can function as a means of conflict prevention by reducing misperception and improving communication between defense establishments (Cottey & Forster, 2004b; Laksmana, 2012; Pounpunwong, 2026). The important point is that defense diplomacy should not be interpreted as eliminating the security dilemma. Instead, it manages the effects of the security dilemma. States continue to pursue their respective national and territorial interests, but defense diplomacy provides institutionalized channels through which these interests can be pursued with a lower risk of unintended escalation. The findings therefore support the view that defense diplomacy is compatible with a neorealist understanding of international relations: it does not replace self-help behavior but provides states with mechanisms for managing the risks generated by that behavior (No et al., 2026). This also explains why communication became particularly important after periods of armed confrontation. Once military activities have generated mistrust, restoring communication becomes necessary not simply for diplomatic symbolism but for reducing uncertainty about actions on the ground. Consequently, the contribution of defense diplomacy lies partly in transforming potentially destabilizing military interactions into regulated interactions in which information, consultation, and restraint become possible. Bilateral and Regional Mechanisms in De-escalation The findings further demonstrate that defense diplomacy in the Thailand-Cambodia conflict operates through both bilateral and regional mechanisms. The bilateral level remains fundamental because Thailand and Cambodia are the parties directly responsible for military activities along the border. Regional mechanisms involving ASEAN, however, provide an additional layer of facilitation and monitoring when bilateral relations become highly contentious (Kongsuwan et al., 2026). At the bilateral level, defense diplomacy is particularly important because security-related decisions ultimately require cooperation between the two states’ defense establishments. The General Border Committee, military-to-military communication, and commander-level interaction provide channels through which political and security agreements can be translated into practical arrangements for managing military activities. The findings therefore reinforce the importance of bilateral defense institutions in conflict management (Tokan et al., 2026). Regional involvement cannot substitute for direct communication between the parties whose forces are positioned along the disputed border, because the implementation of military-related arrangements ultimately depends on their cooperation (Lee, 2026). ASEAN performs a different but complementary function. Its involvement provides diplomatic space for dialogue and supports mechanisms intended to maintain the cessation of hostilities. The ASEAN Chair’s role during the 2025 escalation and subsequent involvement in ceasefire-related processes illustrate how regional diplomacy can support bilateral conflict management (Dinh Co et al., 2025). ASEAN’s role should nevertheless be distinguished from direct defense diplomacy. Foreign ministers’ meetings and ASEAN diplomatic statements are primarily forms of political and regional diplomacy. They become directly relevant to defense diplomacy when they facilitate or support mechanisms involving military communication, ceasefire implementation, troop restraint, or monitoring (Dinh Co et al., 2025). This distinction is important because it prevents the concept of defense diplomacy from becoming excessively broad. Not every diplomatic activity involving a conflict constitutes defense diplomacy. The findings suggest that its defining feature lies in the relationship between the mechanism employed and the management of defense or military interaction. Accordingly, ASEAN’s role is best understood as supportive regional conflict management, while defense diplomacy is most directly observable through defense institutions, military communication, security coordination, and military-related implementation mechanisms (Kim, 2026). The regional dimension also demonstrates the limitations of ASEAN’s role. ASEAN can facilitate communication, encourage restraint, and support monitoring, but its effectiveness depends substantially on the willingness of Thailand and Cambodia to accept regional involvement and comply with agreed arrangements. Thus, ASEAN should not be interpreted as replacing state agency. Rather, its contribution lies in providing an additional institutional channel through which bilateral conflict-management efforts can be supported (Perwita et al., 2022). This finding therefore qualifies the broader claim that defense diplomacy automatically strengthens ASEAN centrality or produces regional stability. The evidence is sufficient to demonstrate ASEAN’s facilitative involvement in conflict management, but it does not by itself establish a broader causal effect on Southeast Asian security stability. Such broader implications should consequently be treated as analytical implications rather than direct empirical outcomes. From Ceasefire to Monitoring: The Limits of Defense Diplomacy One of the most important findings is that ceasefire arrangements represent a transition point rather than the endpoint of conflict management. A ceasefire can stop or reduce immediate violence, but its sustainability depends on whether the parties establish mechanisms capable of managing subsequent military interactions (No et al., 2026). In the Thailand-Cambodia case, the development from ceasefire arrangements toward military communication, troop-position arrangements, coordination, and monitoring demonstrates this shift from the cessation of violence toward the management of post-ceasefire security relations (Simo et al., 2025). The documented arrangements therefore indicate that the ceasefire functioned as an entry point for a broader set of military and institutional measures rather than as a standalone mechanism. This distinction is also important for understanding confidence-building measures (CBMs). A ceasefire should not automatically be classified as a CBM. A ceasefire primarily constitutes an agreement to stop hostilities (Hyma et al., 2026). It becomes part of a broader confidence-building process when accompanied by measures that increase transparency, regulate military behavior, facilitate communication, or provide mechanisms for monitoring and verification. In the case examined here, the subsequent arrangements provide more specific evidence of these functions. The Joint Declaration of 26 October 2025 included provisions concerning military de-escalation, the removal of heavy and destructive weapons, restraint in military activities, confidence-building measures, humanitarian demining, and the continuation of bilateral mechanisms such as the General Border Committee (GBC) and Regional Border Committee (RBC). These provisions indicate that confidence building was linked to concrete efforts to regulate military behavior and reduce the risk of renewed confrontation. Accordingly, military communication, restrictions concerning troop movements and positions, limitations on reinforcement and provocative actions, and monitoring arrangements provide stronger evidence of confidence-building and risk-reduction functions than the ceasefire declaration itself (ASEAN Secretariat, 2022). The monitoring dimension is particularly significant because ceasefire arrangements can remain vulnerable when each party interprets compliance differently. Monitoring mechanisms provide an institutional means of observing implementation and addressing potential violations (Kongsuwan et al., 2026). In this respect, the ASEAN Observer Team represents an important development in the conflictmanagement process because its strengthened role provides a verification-related component to the broader ceasefire framework. The arrangements following the Third Special General Border Committee meeting of 27 December 2025 further demonstrate this function by providing for monitoring of the implementation of the agreed ceasefire arrangements. The function of such mechanisms is not to resolve the territorial dispute but to reduce uncertainty concerning compliance and limit the possibility that individual incidents will develop into renewed confrontation (Lee, 2026). The findings also indicate that confidence building operated through a combination of bilateral and regional mechanisms. Bilateral mechanisms remained central because Thailand and Cambodia retained responsibility for implementing military-related arrangements through their defense institutions, military communication channels, and border committees. Regional monitoring through the ASEAN Observer Team provided an additional layer of observation and support for implementation. This combination is significant because it shows that confidence building did not depend exclusively on regional involvement; rather, regional mechanisms complemented bilateral arrangements by supporting transparency and verification. The evidence therefore suggests that the effectiveness of monitoring depended on the interaction between regional observation and the continued cooperation of the two parties. However, the findings also demonstrate the limits of these mechanisms. Monitoring and communication cannot independently resolve disagreements concerning territorial delimitation and demarcation. Nor can they eliminate the strategic interests and threat perceptions of the two states. Consequently, defense diplomacy may produce a form of negative peace, characterized by the reduction or cessation of direct violence while deeper political and territorial disagreements remain unresolved (No et al., 2026). This finding is particularly important for distinguishing conflict management from conflict resolution. The documented process shows movement from confrontation toward communication, military restraint, monitoring, and deescalation, but there is insufficient evidence to conclude that defense diplomacy has produced a comprehensive resolution of the underlying dispute. Defense diplomacy therefore appears to be most effective when understood as a mechanism for containing escalation, reducing military uncertainty, and creating space for longer-term political processes, rather than as a substitute for those processes. Theoretical and Practical Implications The findings contribute to the understanding of defense diplomacy by demonstrating how the concept operates within an active interstate conflict rather than only during periods of peacetime defense cooperation. Existing conceptualizations commonly emphasize defense diplomacy as a means of confidence building, defense cooperation, and conflict prevention (Marolov & Galeva, 2026; Setyaningsih, 2018). The Thailand-Cambodia case extends this understanding by demonstrating that these functions can also operate during periods of active or recently active confrontation, where defense diplomacy becomes concerned with military communication, restraint, ceasefire implementation, and monitoring (Setyowati & Nurulita, 2023). Theoretically, the findings indicate a complementary relationship between neorealism, the security dilemma, defense diplomacy, and conflict management. From a neorealist perspective, uncertainty regarding the intentions and capabilities of other states can generate incentives for states to adopt measures intended to protect their security. In a contested border environment, such dynamics may contribute to reciprocal threat perceptions and increase the risk of escalation (Gunawan, 2024; Sarjito & Susanto, 2026). The security-dilemma perspective further helps explain why measures intended to enhance security may be interpreted as threatening by the opposing party. Defense diplomacy provides a mechanism through which these security-related interactions can subsequently be managed through institutionalized communication, defense cooperation, confidence building, and military engagement (Cottey & Forster, 2004b; Tan & Singh, 2012). Conflict-management theory provides the final analytical link by explaining the function of these mechanisms. Conflict management concerns efforts to contain or regulate conflict and its consequences without necessarily eliminating the underlying incompatibilities between the parties (Bercovitch & Jackson, 2001). In the Thailand-Cambodia case, ceasefire arrangements, military-to-military communication, restrictions on military activities, bilateral coordination, and monitoring mechanisms are therefore interpreted primarily as conflictmanagement instruments. Their contribution lies in reducing the intensity of military confrontation and regulating interactions between the parties, rather than resolving the underlying territorial disagreement. The resulting analytical relationship can therefore be summarized as follows: security competition and uncertainty generate escalation risks; the security dilemma can intensify reciprocal threat perceptions; defense diplomacy provides institutional and military channels through which these risks can be managed; and the resulting communication, coordination, restraint, and monitoring mechanisms facilitate de-escalation and conflict management. Longer-term conflict resolution, however, remains dependent on political and territorial negotiations beyond the immediate function of defense diplomacy. This interpretation provides a clearer theoretical explanation of why defense diplomacy can be significant even when it does not produce a final settlement (Indrawan & Pratomo, 2021). From a practical perspective, the findings suggest that defense diplomacy should prioritize the continuity and institutionalization of military communication during and after periods of escalation. Commander-level communication, bilateral defense mechanisms, and monitoring arrangements are particularly important when political relations are strained because they preserve channels through which incidents can be clarified and managed before they escalate (Kongsuwan et al., 2026). In this context, the Thailand-Cambodia case demonstrates the practical relevance of maintaining direct communication and bilateral institutional mechanisms alongside ceasefire implementation and monitoring arrangements. Regional actors such as ASEAN can complement these mechanisms by facilitating dialogue and supporting agreed monitoring arrangements. Such regional involvement can strengthen the broader conflict-management process, particularly when bilateral relations become highly contentious, while its effectiveness remains dependent on the cooperation of the parties directly involved (Kim, 2026). Accordingly, ASEAN should be understood as a complementary mechanism that supports bilateral defense and conflict-management arrangements rather than as a substitute for direct bilateral responsibility. The findings also suggest that the sustainability of deescalation depends on the institutionalization of communication and verification rather than on ceasefire declarations alone. A ceasefire is more likely to contribute to sustained conflict management when supported by clear arrangements concerning military conduct, communication, troop positions, monitoring, and procedures for addressing incidents. These mechanisms should therefore be understood as important components of defense diplomacy in situations where territorial disputes continue to generate security dilemmas. Overall, the study argues that the principal contribution of defense diplomacy in the Thailand-Cambodia conflict is not the resolution of the territorial dispute but the management of its security consequences. Defense diplomacy provides channels through which military confrontation can be transformed into communication, coordination, monitoring, and restraint. Its role is therefore best understood as a bridge between immediate conflict management and the longerterm political processes required for conflict resolution.

Conclusion

The documentary evidence directly demonstrates that Vie This study examined defense diplomacy in the ThailandCambodia conflict by focusing on the actors involved, the security issues addressed, and the processes through which defense diplomacy contributes to de-escalation and conflict management. The findings demonstrate that defense diplomacy operates primarily through the interaction of state, defense, and military actors at the bilateral level, complemented by regional mechanisms involving ASEAN. Thailand and Cambodia remain the principal actors because they possess direct authority over military activities and the implementation of security arrangements along the border, while ASEAN provides a supporting role through diplomatic facilitation and ceasefire-related monitoring mechanisms. The study further finds that the main security issues addressed through defense diplomacy concern the management of military activities and the risks associated with renewed escalation. These include ceasefire implementation, troop positions and movements, military-tomilitary communication, monitoring, and the management of incidents along the border. Such mechanisms are particularly important in a conflict characterized by uncertainty and mutual threat perceptions. Rather than eliminating the security interests of either state, defense diplomacy provides channels through which military interactions can be communicated, coordinated, and regulated. Regarding the processes through which defense diplomacy contributes to conflict management, the findings indicate a gradual movement from armed confrontation toward ceasefire, bilateral communication, coordination, and monitoring. This process demonstrates that defense diplomacy can help transform direct military confrontation into more regulated forms of interaction. Its contribution is therefore most evident in maintaining communication, reducing uncertainty, supporting restraint, and facilitating the implementation of ceasefire arrangements. The involvement of ASEAN adds a regional layer to this process, although its role remains primarily facilitative and dependent on the willingness of Thailand and Cambodia to implement agreed arrangements. The central conclusion of this study is that defense diplomacy in the Thailand-Cambodia conflict functions more effectively as an instrument of conflict management and deescalation than as an instrument of conflict resolution. Defense diplomacy can reduce the immediate security consequences of the conflict and create conditions for continued dialogue, but it does not by itself resolve the underlying territorial disagreements between the two states. Consequently, the continuation of de-escalation should not be interpreted as evidence that the broader dispute has been resolved. Longerterm conflict resolution remains dependent on sustained political and diplomatic processes addressing the underlying border issues. The study contributes to the literature by connecting the security dilemma, defense diplomacy, and conflictmanagement perspectives within a single analysis of an active interstate border conflict. The findings show that defense diplomacy can be understood as a practical mechanism linking structural security competition with efforts to regulate military interaction. In this sense, defense diplomacy does not eliminate the security dilemma but provides institutional channels through which its escalation risks can be managed. Several limitations should be acknowledged. First, the study relies primarily on publicly available documentary sources, including official government and ASEAN documents, academic literature, and credible media reports. Such sources may reflect the political positions and strategic narratives of the actors involved. Second, the single-case design limits the generalizability of the findings to other interstate conflicts. Third, the study cannot independently verify all contested claims made by the parties or directly observe military activities on the ground. Finally, the temporal focus on developments during 2025–2026 limits the assessment of longer-term outcomes beyond the period examined. Future research could extend this analysis through comparative studies of defense diplomacy in other Southeast Asian border conflicts or through interviews with defense officials, military personnel, diplomats, and regional institutions. Such research could provide further insight into how defense-diplomacy mechanisms operate in practice and whether the communication and monitoring mechanisms identified in this study contribute to more durable forms of conflict management. Overall, the Thailand-Cambodia case demonstrates that the value of defense diplomacy lies not in replacing political conflict resolution, but in creating the security conditions necessary for confrontation to be contained and dialogue to continue.

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