A brief lesson in Thai-Cambodian political history

On Friday, Thai Prime Minister Paetongtarn Shinawatra was removed from office after it was discovered that she had made a phone call to former Cambodian Prime Minister Hun Sen on June 15.

The call was made two and a half weeks after a brief skirmish took place between the two countries on May 28, and about a month and a half before gunfire was exchanged along the Thailand-Cambodia border.

The two political families have historically been close, and on the call, Shinawatra referred to the now-rival nation’s former leader lovingly as “uncle” and promised to take care of him. During the call, she also disparaged a Thai military commander. After the phone call leaked, protests erupted across Thailand, with many calling her an “enemy of the state.” Government officials called her phone call an ethical breach.

The conflict between Thailand and Cambodia grew into violent and fatal gunfire exchange on July 24. According to the BBC, the conflict escalated rapidly—Cambodia launched rockets, and Thailand retaliated with airstrikes on Cambodian military positions. The tensions have left more than 40 people dead on both sides, including soldiers and civilians, and more than 25,000 displaced. On July 28, a ceasefire was agreed upon, mediated by the United States, but this is not a new dispute between the two Southeast Asian countries, making the recent truce a shaky one. 

To understand what the two nations are fighting about, it’s important to understand their colonial histories. At its core, the clashes are tied to a piece of land surrounding an ancient temple, Preah Vihear, and the colonial-era borders that were created and still shape geopolitics in Southeast Asia today.

The border between Thailand and Cambodia has been contested for more than 100 years. In the 19th Century, Cambodia became part of French Indochina, and Siam (now known as Thailand) escaped colonization by ceding land and territories to France and Britain. Treaties were signed to help Thailand remain a sovereign nation, but in return, carved away at land that still remains disputed today.

Of this land, the most contested piece is the Preah Vihear temple, an ancient Khmer temple dedicated to the Hindu god Shiva. Built sometime between the ninth and 12th centuries, the temple itself is positioned on a cliff in the Dângrêk Mountains, falling right along the border that overlooks Cambodia. Thailand, however, provides the easiest access point to the temple. In 1907, during the French protectorate, maps were drawn that placed Preah Vihear within Cambodian territory. 

Thailand contested this decision, arguing that the temple should fall within its borders—especially since it provides easy access—citing the 1904 map of the region. In 1962, the dispute went to the International Court of Justice (ICJ), which ruled that the temple itself belonged to Cambodia but the surrounding land remains highly ambiguous. This vagueness has fueled repeated clashes between the two countries, notably a series of violent incidents, including government involvement, which led to fatalities that erupted in 2008 when UNESCO declared the Preah Vihear temple a World Heritage site.

The ongoing conflict has been further fueled by the internal politics of both countries.

Thailand, despite escaping colonization, still built its modern state around a centralized authority. The monarchy and military remain powerful institutions, with the military repeatedly intervening in politics through coups, especially in recent history. The now-former prime minister comes from the Shinawatra family, who has had a powerful hold over Thai politics and governance for decades. In recent years, democratic movements, particularly youth-led protests, have pushed for reform, but authorities have cracked down on dissent.

Cambodia’s modern political history is a different story. After decades of French colonial rule, the country endured the Khmer Rouge, a genocide that claimed the lives of about a quarter of the country (between an estimated 1.5 million and two million people). This was followed by years of Vietnamese occupation and then by Prime Minister (and former member of the Khmer Rouge) Hun’s almost four-decade regime. In 2023, when he finally stepped down, Hun Manet, his son, took over to continue the family’s dominance. Against this politically fragile backdrop is how last month’s border clash intensified.

Around the world, conflicts and proxy wars have erupted in the past few years. Russia’s war in Ukraine has raged on since 2022. Israel’s war on Gaza, which has escalated to cause famine, continues to destabilize the Middle East. India and Pakistan recently exchanged gunfire across their disputed border in Kashmir. And global trade wars, particularly between the United States and China, are reshaping allyship among countries across the globe. Southeast Asia is no longer immune to this broader, global pattern.

With this lens, the border clashes are also about where Thailand and Cambodia position themselves in the larger global view. Thailand maintains close ties with the United States, while Cambodia relies heavily on Chinese support, economically and politically. What may seem like a simple border conflict, therefore, becomes entangled in broader global rivalries. The ceasefire—which was imposed by the United States with threats of sanctions, rather than negotiated regionally—reinforces the extent to which external powers continue to shape outcomes in Southeast Asia.

For now, the gunfire has ceased, but as long as Preah Vihear remains a contested symbol and global powers continue to shape the region’s politics, long-term peace will remain precarious for the two countries.