Cambodian soldiers speak with Thai soldiers at the disputed ancient Khmer temple Prasat Ta Muen Thom, or Prasat Ta Moan Thom in Khmer, on the Cambodian-Thai border in Oddar Meanchey province on March 26, 2025. Credit – Tang Chhin Sothy—AFP/Getty Images
Both Cambodia and Thailand have been rated among the friendliest nations in the world, and just five years ago, the Southeast Asian neighbors thought their friendship with each other could never be broken. “As we share a long border, we both know that we have to live and grow together,” Thailand’s then-Ambassador to Cambodia Panyarak Poolthup told Cambodia’s then-Prime Minister Hun Sen. “The political will is always there to resolve any issues that may arise.”
But in recent weeks, bilateral relations have sunk to a dangerous new low, threatening to reignite a historic rivalry that had seemed to be a relic of the past.
Following weeks of standoff, including Cambodia invoking the language of “war,” since a Cambodian soldier was killed in a clash along the border last month, Thai Prime Minister Paetongtarn Shinawatra issued her strongest rebuke yet, signaling resolution likely remains distant.
“Thailand is united. We will not tolerate maltreatment, accusations or threats from any party. Our country also has dignity. Our country is also strong,” Paetongtarn said, in response to Cambodia retaliating with cross-border embargoes and taking the dispute to the International Court of Justice, which Thailand does not recognize the jurisdiction of.
Here’s what to know about the conflict—and its potential consequences.
What has happened in recent weeks?
The reescalation of conflict was sparked on May 28, when a Cambodian soldier was killed in an early morning clash between both nations’ troops, in an area called the Emerald Triangle—the shared border between Thailand, Cambodia, and Laos. The area remains disputed as both Thailand and Cambodia lay claims to parts of the region.
Both sides argued that the other was the aggressor: Cambodia’s Ministry of National Defense said the Thai army opened fire on a trench that had been a Cambodian army base, leading to the death of the soldier, while Thailand’s army claimed that its soldiers responded only after the Cambodian forces “started using weapons” during a misunderstanding in the disputed area.
Hun Sen, who relinquished the Cambodian premiership to his son in 2023 but became the Senate President and remains the effective country leader, reacted to the skirmish, saying that he supports the “decision to send troops and heavy weapons to the border to prepare for a counterattack in case of a further invasion.”
“We hate war, but we are compelled to wage it when facing foreign aggression,” Hun Sen said.
As members of the regional bloc Association of Southeast Asian Nations, Cambodia and Thailand are expected to resolve disputes peacefully, per the ASEAN charter. While both countries initially beefed up military presence on their respective sides of the border, on June 8, they appeared to attempt a deescalation by sending their troops back to military positions that were agreed upon last year. Paetongtarn, in a statement, said the countries agreed “to jointly adjust military forces at points of conflict to reduce the atmosphere of confrontation.”
But the dispute escalated through punitive tit-for-tat policies seemingly designed to appease fomenting nationalistic sentiment on their respective sides of the border.
The Thai army took control of border checkpoints and Bangkok threatened to cut electricity and the internet to Cambodia. Cambodia responded by banning Thai media like TV and movies, and disconnecting cross-border internet links to Thailand. On June 17, Cambodia banned Thailand’s export of produce into the country. Thailand, meanwhile, barred Thais from crossing the border to work in casinos and other entertainment venues in Cambodia’s Poipet.
Further inflaming tensions, Cambodian Prime Minister Hun Manet announced on Facebook on June 16 that Cambodia sent an official letter to the International Court of Justice to help find a solution to the border development issues. “Cambodia chooses international law and peace,” he said the day before.
Thailand’s foreign ministry has ruled out an intervention from the ICJ and made clear its preference for bilateral talks, arguing that “a third party may not always be conducive to the preservation of amicable relations among States, particularly in sensitive matters involving complex historical, territorial, or political dimensions.”
What is the historic context?
Cambodia and Thailand share an 817-km. land border, but that border was largely mapped by French colonizers while they occupied Cambodia from 1863 to 1953. A 1907 map was based on an agreement to follow a natural watershed line between Thailand and Cambodia. But Thailand later contested the map over the fact that it placed the 11th-century Preah Vihear Temple in the Dângrêk Mountains within Cambodian territory.
The dispute, as well as historical differences in cartographic methods, led to areas around the border that both countries lay claim to.
There have been attempts to clarify demarcations. Cambodia brought Thailand to the International Court of Justice in 1959 over the temple dispute, and in 1962 the court ruled in Phnom Penh’s favor, saying that Preah Vihear falls in Cambodian territory. Thailand recognized this at the time but argued that the surrounding frontiers were still disputed, which further complicated the borderlines.
Tensions flared in 2008 when Cambodia sought a UNESCO world-heritage status for the Preah Vihear Temple. After the temple received the recognition in July, military clashes between Cambodian and Thai troops erupted near the border area.
These clashes lasted for years, coming to a head in 2011, after displacing 36,000 at the height of the conflict in April that year. Around this time, Cambodia took to the ICJ again to interpret its earlier 1962 ruling, and the court affirmed its previous decision two years later.
Thailand has pushed for a more bilateral approach, with a Joint Boundary Commission (JBC) established in 2000 to help resolve border disputes. Cambodia has engaged with Thailand through the JBC, but these meetings—the latest of which was scheduled on June 14 in Phnom Penh—tend to produce no significant results.
What could come next?
Resolving the border dispute quickly seems unlikely.
Complicating matters is the relationship between the two countries’ current leaders—and their fathers. Paetongtarn’s father former Thai Prime Minister Thaksin Shinawatra and Cambodian Prime Minister Hun Manet’s father Hun Sen have a public friendship, with Hun Sen even providing refuge to Thaksin in Cambodia and naming him as an honorary economic adviser after Thaksin was ousted in a coup in 2006.
The relationship between the two has caused concern about how the border dispute will be resolved, particularly for Thailand.
When Paetongtarn was asked about whether she’s becoming “too soft” on Cambodia because of the relationship, she responded: “Even though our two families are friends, it doesn’t mean we would allow the country to lose its interests … if a friend asks for your house, no friend would just give it away.”
Paetongtarn’s comments come as the Royal Thai Army said it was ready for a “high-level operation” if necessary to address the situation at the border. Paetongtarn has reiterated calls for a peaceful resolution to the dispute, but being at odds with the Army has echoes of previous government downfalls: both her father Thaksin and aunt Yingluck Shinawatra, another former Prime Minister, were ousted following nationalists groups’ revival of border issues.
In an analysis for Asian current affairs magazine The Diplomat, Royal University of Phnom Penh’s Center for Southeast Asian Studies researcher Rath Pichanvorlak warned that the Thai military “could allow border tensions to escalate, inflaming nationalist sentiment,” to justify another coup.
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