Thailand–Cambodia border agreement on shaky ground

 

 

 

Published: 19 November 2025


    Ryan Claffey
    Center for a New American Security


In Brief

Thailand–Cambodia relations face renewed uncertainty as just two weeks after signing the Kuala Lumpur Peace Accord, Thailand has approved a temporary suspension of the deal. Preventing further conflict will require sustained political resolve from both sides, reinforced by solid bilateral and multilateral mechanisms and genuine regional ownership. Complementing these domestic and regional incentives, sustained external pressure, economic engagement and humanitarian support will further ensure that the fragile detente can mature into a lasting peace.


On 26 October 2025, US President Donald Trump presided over Cambodia and Thailand’s signing of the Kuala Lumpur Peace Accord — a joint declaration expanding the 28 July ceasefire, which halted the bloodiest Thailand–Cambodia border conflict in over a decade. Yet on 11 November, the Thai National Security Council approved a temporary suspension of the accord, suggesting that a more permanent peace will require more than just a tariff-enabled truce.

Tensions first flared in the Preah Vihear temple area on 28 May. Ambiguous border demarcations dating back to 1904 and 1907 French colonial-era treaties have kept adjacent territories — and several temple sites — contested. After two months of unsuccessful attempts by Malaysia and subtle nudging from China to defuse the crisis, on 24 July the simmering dispute escalated into armed clashes across several areas along the frontier, including around the Ta Muen Thom temple.

Even by 25 July, as skirmishes threatened all-out war, Bangkok still resisted third-party mediation. Frustrated, Trump took to Truth Social on 26 July to announce that he had spoken with Cambodian Prime Minister Hun Manet. Following a similar call with Thailand’s prime minister, Trump relayed Bangkok’s willingness to negotiate to Phnom Penh and confirmed that ‘Both Parties are … looking to get back to the “Trading Table” with the United States, which we think is inappropriate to do until such time as the fighting STOPS’.

Though China remains Cambodia and Thailand’s top trading partner, the United States is their primary export market, with exports to the United States equivalent to 27 per cent of Cambodia’s GDP and 12 per cent of Thailand’s. Should the violence persist, Trump threatened to proceed with the planned 36 per cent tariffs on both Cambodian and Thai exports that would take effect on 1 August. The credible prospect of tariff relief, contingent upon mutual restraint, helped drive both sides towards dialogue.

Malaysia’s role was also pivotal. Though mediation is not formally required of the ASEAN chair, the peaceful settlement of disputes between member states remains one of ASEAN’s core principles. Malaysian Prime Minister Anwar Ibrahim, a proponent of ‘constructive intervention’ since 1997, seized the initiative by offering neutral ground, securing a framework that enabled Malaysian-led multilateral monitoring in Cambodia and a phased withdrawal of forces. His deft diplomacy earned ASEAN renewed credibility. The signing of the Kuala Lumpur Peace Accord is a testament to his efforts — ending a conflict that killed 48 people and displaced 300,000 others.

Yet it was US leverage — personally applied by Trump — that provided the initial breakthrough. Trump’s tariff tactics, paired with diplomacy, offered an off-ramp, de-escalating tensions and enabling Anwar’s intervention. Together, Washington and Putrajaya expanded the ceasefire’s scope to include the withdrawal of heavy weapons, the clearing of ordnance and a pathway towards joint management of disputed territories.

Still, risks remain. A week before the signing, Thailand had already contemplated withdrawing from the General Border Committee, a key forum for resolving Thailand–Cambodia border disputes. Following injuries to four Thai soldiers from landmines on 10 November, the Thai military paused its participation in the forum. Though Thailand’s Prime Minister Anutin Charnvirakul initially assured Phnom Penh that the 18 Cambodian soldiers held by Thailand would be ‘promptly’ repatriated, the Royal Thai Army later linked their release to the withdrawal of heavy weaponry. Given Thailand’s suspension of the peace accord, the scheduled 12 November release of the soldiers has been delayed indefinitely.

Domestic politics are also already threatening the truce. While the accord prohibits inflammatory rhetoric, it lacks a formal enforcement mechanism, making compliance among political and military leaders especially difficult. Anutin described Cambodia as an ‘adversary’, reflecting the political incentives he faces in Thailand to stoke nationalist sentiment ahead of the 2026 elections. His predecessor was ousted precisely because her remarks on the conflict were deemed too conciliatory by the military and Constitutional Court.

Cambodia must balance anti-Thai sentiment while also tackling scam centre networks that have become a bilateral and international irritant. Sustaining peace will require disciplined incident management, humane detainee repatriation and restraint in escalatory actions or rhetoric that could quickly reignite the conflict. Reconciliation requires courage and political resolve from leaders on both sides.

Trump’s initial intervention was instrumental. Yet to secure both countries’ adherence to the accord, Washington must pair continued diplomatic pressure with tangible humanitarian support — demining, providing shelters and medical aid — and economic engagement. Strengthening trade relationships will be particularly important given China’s growing economic influence. Keeping the peace also requires fostering expertise on Southeast Asia within the US State Department and National Security Council, and revitalising programs previously administered by USAID. China is already moving to fill the gap. Consistency is what converts temporary leverage into enduring influence.

After suspending participation in the accord, Anutin curtly dismissed the importance of the US–Thai trade relationship, suggesting Thailand had alternative economic options. Yet after Trump’s suspension of bilateral trade talks, in a phone call on 15 November, Anutin swiftly changed his tone, seeking a resumption of talks and further tariff reductions — highlighting persistent US influence even as Thailand pursues diplomatic diversification, exemplified by the king’s recent state visit to Beijing. Washington’s intervention worked once again. Now, it should leverage Thailand’s renewed commitment and its own growing relationship with Cambodia to ensure Phnom Penh fully complies with demining procedures, and that both sides calm the rhetoric and stop the shooting.

The signing in Kuala Lumpur was only the beginning. Despite a joint declaration, Thailand’s suspension of the accord highlights that the possibility of a future conflict remains. As the ASEAN Observer Team takes shape, active participation from all parties will be crucial. The accord’s longevity hinges on the effectiveness of bilateral and multilateral mechanisms, a genuine sense of regional ownership and continued external pressure. Yet only by addressing the root causes of a dispute that dates back decades can a delicate detente mature into a durable peace.

Ryan Claffey is Research Assistant with the Indo-Pacific Security Program at the Center for a New American Security (CNAS).