Cambodia and Thailand are fighting again. What happened to Trump’s peace deal?

BANGKOK – Long-simmering tensions between Thailand and Cambodia boiled up into five days of clashes in July, leaving almost four dozen people dead and displacing more than 300,000 from their homes. 

Three months later, during a trip to Asia, US President Donald Trump brokered what he called the “Kuala Lumpur Peace Accords” in which the neighbours agreed to withdraw heavy weapons from border regions and settle their disagreements.  

The uneasy calm was short-lived and, by early December, a new bout of violence was threatening to derail the deal that Mr Trump had backed up with a threat of trade retaliation. If he decides they have betrayed the terms of the peace agreement and reinstates heavier US tariffs on goods from the two countries, it could deal a blow to Thailand’s export-reliant economy just as it gears up for an election in 2026. 

How did the conflict between Cambodia and Thailand start?

The clashes in July were the result of disagreements stretching back more than a century and involving parts of a region known as the Emerald Triangle, where the boundaries of Thailand, Cambodia and Laos meet. 

The spark for 2025’s violence was the killing in May of a Cambodian solider during an exchange of gunfire in one of the disputed areas, Chong Bok. Both sides blamed each other for initiating the clash. The two countries amassed troops along much of the roughly 800km frontier and restricted land crossings that serve as vital trade routes.  

All-out conflict broke out in late July after two Thai soldiers stepped on landmines during routine patrols, with each soldier losing a limb in the separate incidents. Thailand accused Cambodia of recent mine-laying and issued a strong condemnation. Cambodia denied the mines were new and said Thai soldiers had strayed from their patrol routes and ventured into Cambodian territory. 

The two countries cut diplomatic ties and Thailand lodged complaints against Cambodia under the United Nations Anti-Personnel Mine Ban Convention, to which both countries are parties. The clashes spread to all border provinces and involved heavy artillery, rockets, fighter jets and the Thai navy. Each side claimed it was attacking in self-defence, and Thailand warned it could potentially evolve into a war.  

How was a ceasefire reached? 

Days after the all-out conflict erupted, Trump threatened to freeze trade deals with Thailand and Cambodia – which both faced 36 per cent tariffs on exports to their biggest market – unless they stopped fighting. He called Cambodian Prime Minister Hun Manet and then acting Thai leader Phumtham Wechayachai to broker a ceasefire, and the two sides agreed to talks. 

Malaysian Prime Minister Anwar Ibrahim hosted the negotiations in the city of Putrajaya in late July, with US and Chinese envoys in attendance. Datuk Seri Anwar announced an “immediate and unconditional” ceasefire. Mr Trump, who had facilitated the talks, called himself “the President of PEACE”, and lowered the tariffs to 19 per cent. The Thai and Cambodian militaries agreed to set up coordination teams to prevent future conflicts. 

The ceasefire largely held, and was reinforced in October when Mr Trump joined a summit of leaders of the Association of Southeast Asian Nations in Malaysia and presided over the signing of the Kuala Lumpur accords, laying out the steps for Cambodia and Thailand to disarm at the border and normalise diplomatic ties. 

What went wrong?

In early November, another landmine blast injured Thai soldiers and Thailand’s new Prime Minister Anutin Charnvirakul suspended the peace deal, saying he would prioritise national interests and the safety of Thailand’s people over the fate of US trade talks tied to the agreement. A deadly skirmish two days after the blast killed one civilian, Cambodia said. 

The situation deteriorated further in December, with daily clashes leading to the evacuation of more than half a million civilians. Thailand accused Cambodia of launching rockets into populated areas, including near a hospital. Cambodia said Thailand had bombed a village using F-16 combat jets. 

How do Cambodia’s and Thailand’s military capabilities compare?

Thailand has far more military might, with 360,000 active personnel in its armed forces compared with about 124,000 for Cambodia, according to the International Institute for Strategic Studies think-tank. Thailand spends about four to five times more on its armed forces than Cambodia and has one of the region’s most capable militaries. A lot of its equipment comes from the US and Europe, while Cambodia gets almost all of its weaponry from China, much of which is based on older technology. 

Thailand would have the edge in any ground war, with about double the number of tanks and more than five times the number of artillery pieces, according to IISS. Thailand also has a clear advantage in the air, with two squadrons of modern Lockheed Martin F-16s and a squadron of Saab Gripen C/Ds fighters. Cambodia does not have any combat jets. 

What’s the origin of the border dispute? 

The tensions can be traced back to the colonial era and maps that were drawn based on the Franco-Siamese treaties of the early 1900s that laid out the boundaries between Thailand and Cambodia, which was then part of French Indochina. An agreement in 1904 stated that the boundary would follow the line of the watershed between the two countries.

They still dispute the sovereignty of several areas and various efforts to demarcate the boundary have yet to yield results. One flashpoint over the years was the 11th century Temple of Preah Vihear, to which Cambodia lays claim based on a 1907 border map drawn up by French surveyors. Thailand says the site is on its side of the watershed. 

Cambodia brought the issue before the International Court of Justice (ICJ), which ruled in 1962 that the temple belonged to Cambodia. Nonetheless, Preah Vihear has been the scene of intermittent fighting since 2008, when Cambodia applied to secure world-heritage status for the temple from UNESCO, the UN body that deals with education, science and culture. 

The site was at the centre of a deadly clash in 2011. In 2013, the ICJ asserted that its 1962 ruling meant Cambodia had sovereignty over the whole territory of the temple as well. Thailand officially accepted the court’s rulings on Preah Vihear, but the country no longer recognizes the ICJ’s jurisdiction. 

Following the initial skirmish in May, Cambodia submitted a petition to the ICJ to help settle the issue of sovereignty over four disputed areas. Thailand insisted on the use of bilateral resolution mechanisms, such as a Joint Border Commission set up by the two countries in 2000. 

What role has the latest conflict played in Thai politics?

The conflict broke out under the previous administration of prime minister Paetongtarn Shinawatra, who was suspended by the Constitutional Court in July pending an investigation into allegations of ethical misconduct over her handling of the border issue. The investigation was prompted by a leaked phone conversation between her and Cambodia’s former leader Hun Sen, in which she was heard criticising the Thai army.

Mr Anutin, who leads the conservative Bhumjaithai Party, exited Ms Paetongtarn’s coalition immediately after the leak, pushing the government to the brink of collapse. When the Constitutional Court eventually ruled against Ms Paetongtarn and removed her from office, Mr Anutin became Thailand’s new prime minister in a parliamentary vote.

He has taken a tough stance on the Cambodia stand-off to bolster his nationalist credentials ahead of the election. His insistence on protecting Thai sovereignty and pro-military rhetoric have cemented conservative support and won him backing in the populous north-eastern region that shares the border with Cambodia and was traditionally seen as an electoral stronghold for the Shinawatra clan. 

Mr Anutin has insisted the Cambodia dispute is separate from Thailand’s trade negotiations with the US. But if the latest fighting scuppers trade negotiations with the US and Trump imposes a new bout of punishing US tariffs, it could undermine Mr Anutin’s promise of a “quick, big win” on the economy ahead of the vote slated tentatively for March. Bloomberg