The Emerald Triangle Dispute: Why Thailand And Cambodia Are Fighting Again

At least one Thai civilian was killed and three others injured on Thursday as Cambodia launched rockets and artillery in retaliation for Thailand's airstrikes on Cambodian military positions. This has brought the two countries' bilateral ties to the lowest point in decades.

The long-running border dispute centres on the Emerald Triangle, a historically contested region home to ancient temples and overlapping territorial claims.

What Is The Emerald Triangle

The Emerald Triangle, where Thailand, Cambodia, and Laos meet, is rich in temples and jungle terrain, and has long been claimed by both countries. The dispute dates back over a century to a 1907 colonial-era map, drawn when France controlled Cambodia, which placed the Preah Vihear Temple inside Cambodian territory.

In 1962, the International Court of Justice (ICJ) ruled in Cambodia's favour. But Thailand still disputes the land around the temple, arguing it wasn't covered by the ICJ ruling. This has led to repeated clashes.

Tensions flared again in 2008, when Cambodia had Preah Vihear listed as a UNESCO World Heritage site. Military conflict followed, peaking in 2011, when lakhs of civilians were displaced. The ICJ reaffirmed its decision in 2013, but the border remains contested.

What Happened On Thursday?

After weeks of rising tensions, violence erupted along the border. Thailand launched six F-16 jets from Ubon Ratchathani, striking two Cambodian military sites. In response, Cambodia fired rockets and artillery into Surin province.

Each side blamed the other for starting the clash. Cambodia called its response "legitimate self-defence," while Thailand said Cambodia carried out a "targeted attack on civilians."

According to Thai officials, the clash began when a Cambodian drone was spotted near Ta Muen temple, followed by six armed Cambodian soldiers. Thailand said it gave warnings before Cambodia opened fire, prompting the airstrikes.

Why Are Tensions Flaring Now?

The current flare-up began in May, when a Cambodian soldier was killed in a border clash. Since then, both sides have traded blame and reinforced troops. A brief truce on June 8 collapsed quickly.

Thailand accused Cambodia of laying landmines, injuring five soldiers. In response, Cambodia downgraded ties, expelled Thai envoys, banned Thai media, and cut internet links. Thailand then threatened power cuts to Cambodian towns and restricted Thai workers from crossing into Poipet.

On June 17, Cambodian PM Hun Manet said Cambodia had turned to the International Court of Justice. Thailand rejected third-party mediation, insisting on bilateral talks.

Border Dispute Factors

The border dispute is as much about politics as territory. Thailand's suspended Prime Minister Paetongtarn Shinawatra faces mounting pressure from both the opposition and the military, who question her tough stance on Cambodia. Her father, Thaksin Shinawatra, has long been close to Hun Sen, Cambodia's former Prime Minister and now Senate President, who gave Thaksin asylum and named him an adviser after his 2006 ouster.

Critics have questioned whether these family ties are influencing her policies. Paetongtarn Shinawatra dismissed the concerns.

Thailand's military has hinted at a possible "high-level operation" if tensions worsen. 

The conflict threatens to destabilise Southeast Asia's regional balance, especially given both countries' membership in ASEAN, which encourages peaceful conflict resolution.

A peaceful resolution appears unlikely at the moment. The Joint Boundary Commission (JBC), established in 2000 to address border disputes, has made little headway. A meeting scheduled for June 14 in Phnom Penh ended without progress. Cambodia has announced plans to begin conscripting civilians for military service next year.