Congratulating Thailand’s newly endorsed premier, Anutin Charnvirakul on September 7, Cambodian Prime Minister Hun Manet pledged to “work closely” to restore relations “to normalcy,” rebuild trust, and transform the border into a zone of “peace, cooperation, development, and shared prosperity.” Picture source: Depositphotos.

 

Prospects & Perspectives No. 50
 

Whither the Cambodia-Thailand Conflict?
 

  By Bradley J. Murg
 

　Congratulating Thailand’s newly endorsed premier, Anutin Charnvirakul on September 7, Cambodian Prime Minister Hun Manet pledged to “work closely” to restore relations “to normalcy,” rebuild trust, and transform the border into a zone of “peace, cooperation, development, and shared prosperity.” That vocabulary is not ornamental. It points to the only politically sustainable path out of a bruising summer for Thai-Cambodian relations: normalize quickly, reopen systematically, and let border communities resume their ordinary commerce. The letter’s substance and timing, hours after Anutin’s royal endorsement, signal Phnom Penh’s readiness to move from triage to reconstruction if Bangkok will meet it halfway.

　The backdrop is stark. From July 24-28, Cambodia and Thailand fought their deadliest engagements in more than a decade, including Thai air operations near disputed temple zones and heavy exchanges of artillery. A ceasefire announced on July 28 arrested the slide, and on August 7 the two sides accepted ASEAN observers at an Extraordinary General Border Committee meeting in Kuala Lumpur. The humanitarian and administrative costs of the conflict were immediate. Thailand temporarily shut all border checkpoints, evacuated more than 100,000 residents from frontier provinces, and diverted medical capacity as hospitals curtailed services. Cambodian provinces absorbed parallel displacement while contending with landmine scares.    

Conflict dynamics  

　What drove the escalation was less cartography than domestic legitimacy. In Bangkok, months of churn culminated in Anutin’s taking on the top job and inheriting an incentive structure that is brutally simple: consolidate authority by demonstrating control, but avoid becoming owner of a crisis that damages an already weak economy. A nationalist frame — defend the temples, police the line, close the gates — travels easily across factions. The political danger for the new government is not appearing “soft,” it is presiding over stagnation at the border that erodes confidence before cabinet portfolios are even settled.

　In Phnom Penh, the government has already banked the domestic dividends from this crisis, and there is little left to harvest. The sequence is textbook rally-round-the-flag: former prime minister Hun Sen, who is currently president of the senate, stepped to the fore as crisis impresario, saturating Cambodian media and Facebook with commander-in-chief imagery, while Hun Manet acted as the statesman who could both hold the line and accept ASEAN monitoring. The opposition space, already constricted, was smothered by a unifying nationalist script and genuine popular support for the government during the crisis. Even skeptical observers acknowledge that the government converted battlefield peril into political surplus; Reuters described an “outpouring of support” amid a wave of nationalism, and a Council on Foreign Relations analysis argued that the clash helped Hun Sen reassert centrality. By the standards of the past decade, this is a high-water mark, arguably unprecedented in its intensity, for regime popularity and message discipline. Precisely because the nationalist upside has been captured, the marginal returns to prolonging tension have turned negative.

The U.S. steps in

　Washington’s role in this crisis was unusually muscular and, crucially, transactional: the White House paired standard crisis diplomacy with a blunt tariff threat that neither Bangkok nor Phnom Penh could afford to ignore. State Department declarations pressed for an immediate halt to hostilities and endorsed the July 28 ceasefire, but the inflection point came when President Trump personally called Thai and Cambodian leaders and linked de-escalation to the suspension or mitigation of a looming across the board U.S. tariff on most exports from both countries. Within 48 hours, ceasefire talks in Kuala Lumpur snapped into place, and U.S. officials publicly tied renewed trade negotiations to the implementation of the truce. In a region where American influence often travels through alliance habits and quiet security cooperation, this was coercive economic statecraft in the open, and it worked because the immediate, quantifiable costs of a tariff shock would have been severe.

　That success, however, was a one-off born of timing and leverage rather than a replicable template for regional conflict management. The tariff cudgel derived its potency from a confluence of domestic U.S. trade policy and the extraordinary salience of American demand in both economies; it pushed Bangkok and Phnom Penh to the table to avert an imminent hit, not because Washington had discovered a durable formula for arbitration. Even sympathetic observers in the region note that such tools will be hard to deploy repeatedly without collateral damage to broader U.S. economic and diplomatic objectives, especially as ASEAN members jealously guard their centrality and remain allergic to great-power “solutions” that appear to subordinate regional mechanisms. In practice, the United States wisely reverted to supporting ASEAN monitors and shuttle diplomacy once the ceasefire took hold, sharing the stabilizer’s stage with China while letting ASEAN hold the gavel. The net effect is instructive: decisive U.S. pressure created the opening, regional architecture did the maintenance, and both sides moved just far enough to escape a tariff shock that neither could absorb.

China’s role

　Beijing entered the crisis with a clear script and visible choreography. In early July, Foreign Minister Wang Yi told ASEAN foreign ministers in Kuala Lumpur that China stood ready to uphold an objective and fair position and to play a constructive role. Within weeks he met the ASEAN Secretary General in Beijing, cast the dispute as a legacy of Western colonialism, and urged regional solutions, while Chinese diplomats amplified that message at the United Nations. By July 30 senior Thai and Cambodian officials were quietly meeting under the chairmanship of a Chinese vice foreign minister. The sequencing revealed both ambition and tact. China sought to be seen as the indispensable adult in the room, yet it preferred to work behind the curtain and to frame any progress as an ASEAN centered achievement rather than a made in China fix.

　The motives were straightforward. Prolonged fighting along the frontier jeopardizes China’s overland connectivity to mainland Southeast Asia, the broader Greater Mekong Subregion economic agenda, and investor confidence in projects that anchor Chinese influence from Kunming to Cambodia’s coast. Mediation also serves image repair and brand management. After years of scrutiny in the South China Sea, a constructive role on the mainland allows Beijing to present itself as a responsible power consistent with the language of the Global Security Initiative.

　Constraints surfaced just as quickly. Thai media and commentators read Beijing’s early activism through a skeptical lens, pointing to joint Chinese Cambodian exercises in May and accusing China of tilting toward Phnom Penh. Bangkok’s political class remained wary of any channel that smelled like external arbitration, a wariness rooted in memories of contentious International Court of Justice episodes. ASEAN centrality compounded the limit. Malaysia, in its role as ASEAN chair, assembled the decisive meetings and brokered the ceasefire, and there was little appetite to cede the gavel to China or to any new Chinese-led body such as the International Organization for Mediation. Beijing therefore adjusted, endorsing the ceasefire, keeping a seat at the table as an observer, and continuing shuttle style engagement in Shanghai and other venues that preserved influence without provoking backlash. The net effect is that China is present and important, but it remains one stabilizer among several rather than the security manager of first resort.

　China’s role in this dispute illustrates a ceiling that is political rather than material. Beijing has the relationships, the logistics, and the incentives to help, and it can synchronize its moves with ASEAN’s processes. What it lacks is an uncontested license to lead. When the United States applied direct pressure, including tariff threats, and when ASEAN’s chair took ownership of the mediation, Beijing’s activism had to become complementary rather than directive. The region may welcome Chinese reassurance and even Chinese support for monitors and ceasefire maintenance, but it remains reluctant to embrace a unilateral Chinese gavel. That reluctance will persist unless Beijing can convince skeptical publics that its security role is genuinely impartial and consistently subordinate to regional mechanisms.

The limits of consensus

　ASEAN stepped into the Cambodia–Thailand crisis at a moment of profound institutional strain. Four years after Myanmar’s 2021 coup, the bloc’s Five-Point Consensus has largely stalled: violence persists, the junta remains barred from high-level meetings, and member states are split over how far to go beyond quiet diplomacy. Malaysia’s 2025 chairmanship has injected fresh activism, pushing humanitarian access and publicly deeming a junta-run election “not a priority,” but even Kuala Lumpur’s initiatives underscore the limits of consensus in a divided house. Analysts across the region now speak openly of a credibility problem: if ASEAN cannot make visible headway on Myanmar, its claim to regional centrality looks increasingly procedural rather than problem-solving.

　Against that backdrop, the bloc’s coordination on the Thai–Cambodian front is best read as a modest but meaningful success constrained by politics it cannot control. Malaysia convened defense principals and, on August 7, secured agreement for ASEAN observers to help steady the ceasefire, precisely the low-visibility, confidence-building function the organization still performs well when the parties want an off-ramp. Yet the monitors’ effectiveness ultimately depends on Bangkok and Phnom Penh, and ASEAN’s bandwidth is finite while Myanmar drains diplomatic oxygen. In short, the institution remains capable of scaffolding de-escalation at this border, but its leverage is bounded by the same structural weaknesses exposed next door.

　At present, the frontier is quieter than it was in late July but not settled: closures and evacuations have imposed countable trade losses, visible labor shortages, and fiscal strain, while prolonged uncertainty will only become more expensive as both countries enter the economically vital tourism high season. The domestic calculus therefore tilts toward normalization, Anutin gains early political credit from calm, Hun Manet, having already harvested the nationalist dividend, gains from statesmanlike de-escalation while external dynamics set the bounds rather than the script. A one-off U.S. tariff threat created the opening for talks but is not a repeatable tool; China’s activism remains important yet politically capped, folded into ASEAN-led mechanics at a time when the bloc’s credibility is stretched by Myanmar. The workable equilibrium is narrow but clear: empower ASEAN’s monitoring where it functions, keep the border a local problem rather than a proxy theater, and convert a fragile ceasefire into routinized, low-drama cooperation.

(Bradley J. Murg is Provost and Vice-Rector for Academic Affairs at Paragon International University in Phnom Penh and Senior Advisor at the Cambodian Institute for Cooperation and Peace.)