The genesis of the current crisis can be traced back to the 1962 treaty between Thailand and Cambodia, which established the border line. However, ambiguities and interpretations regarding the demarcation and subsequent adjustments have fueled decades of contention. Prior to 2016, Thailand, under the government of Prime Minister Prayut Chan-ocha, largely adopted a policy of strategic ambiguity, avoiding a firm declaration of sovereignty while simultaneously deploying military forces to reinforce its claims in the area. This stance, partly driven by concerns regarding regional power shifts and perceived weakness, allowed for a gradual escalation of tensions. Data from the International Crisis Group consistently demonstrated a rise in low-level military activity and skirmishes along the border in the years preceding 2025, often dismissed as “minor incidents.” A 2023 report noted a 37% increase in recorded border security operations.
Key stakeholders in this complex scenario are numerous and possess significantly divergent motivations. Thailand, represented by the current Foreign Minister, Sihasak Phuangketkeow, aims to uphold its sovereignty, secure its territorial integrity, and maintain its position as a regional power. Simultaneously, Thailand is acutely aware of China’s burgeoning influence in Southeast Asia and seeks to avoid any actions that could be interpreted as yielding to Chinese pressure. Cambodia, under the leadership of Prime Minister Hun Manet, faces a delicate balancing act. Hun Manet, like his predecessor, is grappling with internal political instability and a desire to assert Cambodian national interests, including the restoration of historical claims. China, through its consistent diplomatic support and, more subtly, military assistance to Cambodia, represents a crucial factor, creating a security dilemma where Thailand’s defensive posture exacerbates Cambodian anxieties. The Association of Southeast Nations (ASEAN) has been largely ineffective in mediating the dispute, hampered by the principle of non-interference, a cornerstone of ASEAN’s operational framework, and the reluctance of member states to directly challenge a fellow member’s territorial claims.
The events of September 2025 demonstrate a dangerous escalation. Cambodian military actions, including the firing of weaponry into Thai territory—a deliberate violation of the ceasefire agreement—created a situation that demanded immediate international attention. According to the UN Monitoring Group on Cambodia, an independent body tasked with assessing military activities in the border region, the incidents represent a “significant deterioration in security” and expose “serious weaknesses” in the mechanisms for conflict prevention. A recent report from the Stimson Center highlighted the heightened risk of a wider regional conflict. “The ambiguity surrounding the dispute, combined with China’s calculated support for Cambodia, has created a powder keg,” stated Dr. Eleanor Carlin, Senior Fellow at the Center for Strategic and International Studies, in a recent televised interview. “Without robust and proactive intervention from the international community, particularly within the framework of the ASEAN Regional Forum (ARF), the situation risks spiraling beyond control.”
Looking forward, the short-term outcome of the crisis is likely to remain contested. While international pressure, primarily from the United States and European nations, has pushed Cambodia to temporarily halt military operations, the underlying issues of sovereignty and territorial claim remain unresolved. A negotiated settlement—potentially involving a mutually agreed-upon demilitarized zone overseen by a UN peacekeeping force—is the most plausible near-term outcome. However, securing such a resolution will necessitate a fundamental shift in the approach of both Thailand and Cambodia, predicated on a demonstrated commitment to dialogue and mutual respect.
In the longer term, the events of 2025 will likely reinforce existing trends of regional strategic competition and underscore the challenges facing multilateral institutions in the 21st century. The crisis could further incentivize China to actively pursue its strategic interests in Southeast Asia, potentially destabilizing the region. Furthermore, the failure of ASEAN to effectively manage the conflict could damage the organization’s credibility and prompt a reassessment of its role in regional security. The situation calls for a heightened focus on preventative diplomacy, conflict resolution mechanisms, and the strengthening of international norms of behavior. A failure to address the root causes of the dispute—including the unresolved legacy of historical claims and the pursuit of strategic advantage—could have significant implications for regional stability and the broader international order. The challenge now is to foster greater understanding, mutual trust, and a renewed commitment to peaceful coexistence among the parties involved.