Proposed Thailand-Cambodia Border Wall Needs Clear Demarcation

BANGKOK – Thailand’s recent plan to build a wall on parts of its 817-kilometre border with Cambodia has reignited old debates over security and sovereignty. Acting Prime Minister and Defence Minister Phumtham Wechayachai stressed that no permanent wall can go up unless the border is clearly marked, highlighting the ongoing dispute over territory.

This move comes during a period of rising tension, with recent violence, diplomatic rows, and a fragile truce established in July 2025. As the world keeps a close eye on the situation, many wonder if a border wall would stop illegal activity or stoke more unrest in a region with a long and troubled past.

Disagreements over the border stretch back to the early 1900s, when French colonial authorities in Cambodia drew up the border with Siam (now Thailand). The Franco-Siamese treaties of 1904 and 1907 followed the line of the Dangrek Mountains, but mistakes on French maps, especially around Preah Vihear temple, created future problems.

In 1962, the International Court of Justice (ICJ) awarded Preah Vihear to Cambodia, a ruling Thailand has never truly recognized due to its historical claims and access from the Thai side. Fights broke out again in 2008 after Cambodia pushed for Preah Vihear to become a UNESCO World Heritage Site, sparking protests and new flare-ups along the border.

The latest trouble started in May 2025 with a brief clash near Prasat Ta Muen Thom, a disputed temple. A Cambodian soldier, Second Lieutenant Suon Roun, was killed. Tensions continued to rise until, on July 24, both armies exchanged artillery and rocket fire near the site. Thai authorities reported 15 deaths, mostly civilians, while Cambodia confirmed one civilian death. More than 300,000 people were forced to leave their homes—180,000 in Thailand, 135,000 in Cambodia.

Border Wall Plans: Beyond Security Concerns

The border wall idea first appeared in February 2025 when Phumtham Wechayachai proposed a 55-kilometre barrier in Sa Kaeo province to address problems such as human and drug trafficking. Authorities argue that razor-wire-secured areas are easy targets for illegal crossings, especially near Poipet, a known centre for Cambodia’s cyber scam operations.

In a March 2025 police raid in Poipet, officials freed 215 people, including 119 Thai nationals, from a scam site. Spokesman Jirayu Houngsub explained that the wall project is still under review as a way to fight trafficking, with no final plans or costs shared yet.

Phumtham stated on August 29 that a permanent barrier is only possible after both sides agree on the border itself. This process has stalled, even though a memorandum in 2000 planned joint surveys. Thailand wants to keep talks between the two governments, turning down Cambodia’s calls for ICJ or outside mediation.

This stance shows Thailand’s reluctance to revisit the 1962 ICJ case and its intent to keep full control. Cambodia has not officially responded to the new wall proposal, though analysts think the lack of response is due to internal debates about the importance of Chinese-backed scam syndicates operating from Cambodia.

July’s battles were the worst in years, as both Thailand and Cambodia blamed each other for starting the violence. Thailand claimed Cambodian rockets hit civilian areas, while Cambodia accused Thai troops of breaching agreements by moving closer to the contested temples and using drones.

Both sides deployed heavy weapons, with Thailand using F-16 fighters and Cambodia launching BM-21 rockets. Cambodia also accused Thailand of using cluster bombs, which led to international criticism; Thai officials later admitted these weapons might have been used if they were needed.

Malaysia’s Prime Minister Anwar Ibrahim brokered a ceasefire on July 28, helped by a threat from U.S. President Donald Trump to halt trade talks. Phumtham and Cambodian Prime Minister Hun Manet agreed to an immediate ceasefire at midnight.

Still, reports of more gunfire and accusations of breaking the ceasefire show just how fragile the peace remains. Malaysian monitors are now watching the situation, but doubts linger as the border remains unclear and both countries’ national pride runs deep.

Thailand’s Domestic Politics Shape Responses

The border crisis is linked closely to internal politics. Thailand’s removal of Prime Minister Paetongtarn Shinawatra in June 2025, after leaked calls with ex-Cambodian leader Hun Sen, weakened the Thai government and triggered a surge in nationalist anger.

Phumtham, now acting prime minister, needs to show strength, especially as Thailand holds a military advantage. In Cambodia, Hun Manet governs while his father, Hun Sen, keeps a strong influence, using nationalist sentiment to support his son’s position.

At the regional level, the conflict tests the strength of ASEAN, as Malaysia’s mediation underlines the bloc’s limited ability to shape events. China, supplying arms to both sides and trading with both countries, wants to see calm to protect its interests.

The U.S., with close ties to Thailand, has pressured both sides to ease tensions, with Trump’s actions playing a key part.

While the wall is presented as a way to improve security, it could make tensions worse if built without agreement on the actual border. Cambodia accuses Thailand of aggression, and Thailand claims Cambodia’s use of landmines, despite both countries banning them.

The Joint Boundary Commission, created in 1997, has made little progress, and Thailand refuses to let the ICJ get involved again, making direct talks the only way forward, though these have often stalled.

People living along the border face the hardest effects. In provinces like Surin (Thailand) and Oddar Meanchey (Cambodia), evacuees describe the worst violence since Khmer Rouge times, with homes, hospitals, and schools badly hit.

Some Cambodians tell of their fear as Thai drones fly overhead; Thai villagers in Buriram talk about fleeing rocket fire. For these communities, the ceasefire offers hope, but with no lasting agreement on the border, the wall remains not only a security proposal but also a possible trigger for more trouble.

With both governments under pressure and global attention fixed on the border, Phumtham’s call for a clear agreement before construction hints at caution.

Yet the forces at play—national pride, longstanding grievances, and economic interests—mean the issue will need careful and ongoing diplomacy. For now, the Thai-Cambodian border remains tense, its future still uncertain with the proposed wall at its centre.