The ongoing conflict between Thailand and Cambodia represents a complex intersection of centuries-old territorial disputes, colonial-era borders, cultural rivalry, and nationalist politics.

Here is a balanced historical exploration of why the two Southeast Asian nations are again embroiled in violence in 2025.

1. Deep Historical Roots and Rivalry

From the 9th to the 15th centuries, the powerful Khmer Empire (centered in modern Cambodia) controlled vast regions of what is now Thailand, Laos, and Vietnam.

As the Khmer Empire declined, the Thai kingdom of Ayutthaya rose, eventually sacking Angkor and incorporating Khmer cultural elements while taking over western Cambodian territories. This ancient rivalry set the stage for later disputes and cultural tensions.

2. Colonial-Era Treaties and Border Ambiguities

In the late 19th and early 20th centuries, France colonized Cambodia and Vietnam (forming French Indochina), while Thailand (then Siam) remained independent.

Two critical treaties—signed in 1904 and 1907 between Siam and France—attempted to demarcate the border, especially through the Dangrek Mountains. French mapmakers, however, drew boundaries that sometimes deviated from treaty language, placing territories like the Preah Vihear temple on the Cambodian side, even though it was more easily accessible from Thailand.

These ambiguities left several portions of the border—especially near ancient temple sites—unresolved and open to conflicting interpretations.

3. Modern Political Disputes and World Court Decisions

The border issue flared up visibly in the 1950s, shortly after Cambodia won independence from France. The Preah Vihear temple became a flashpoint, with both nations claiming ownership.

In 1962, the International Court of Justice (ICJ) awarded the temple itself to Cambodia, but did not clearly rule on the surrounding land—about 4.6 square kilometers—which remains disputed.

Tensions simmered until 2008, when Cambodia successfully nominated Preah Vihear as a UNESCO World Heritage Site. This reignited nationalist fervor and sparked military skirmishes as both sides stationed troops and exchanged fire, leading to casualties and displacement.

Further court appeals and international diplomatic efforts—often through ASEAN—failed to permanently resolve the matter.

4. Cultural and Nationalist Rivalry

Beyond legal arguments and ancient maps, there is a fierce nationalist rivalry between Thais and Cambodians. Both claim elements of regional heritage as their own, fueling popular and political tensions. In Cambodia, there is resentment over centuries of Thai dominance and accusations of cultural appropriation.

 In Thailand, nationalist voices assert historical rights to disputed territories. These conflicts extend to controversies over the origins of arts, architecture, and even traditional martial arts like Muay Thai (which Cambodians say evolved from Kun Khmer).

5. Recent Political Dynamics and Escalation

The latest round of fighting in 2025 is fueled by renewed nationalism, unresolved border demarcation, and political maneuvering on both sides. Nationalist parties and leaders have amplified the dispute for domestic political gain, and mutual suspicions have deepened, partly due to personal rivalries among the political elites in both countries.

Recent violence has resulted in hundreds of deaths and the displacement of hundreds of thousands from border areas. The fighting began with skirmishes around temples along the border—including Prasat Ta Muen Thom and Prasat Ta Krabey—before escalating into broader military engagements. Both sides accuse the other of aggression, and social media has amplified enmity among ordinary citizens.

6. International Involvement and Attempts at Resolution

External powers and regional organizations (notably ASEAN, the United States, and China) have urged restraint, pressed for ceasefires, and offered mediation.

Yet, with borders undemarcated in several places and deep mistrust remaining, these efforts have thus far brought only temporary lulls in fighting.

Conclusion

At its core, the Thailand-Cambodia conflict today is the product of colonial-era border ambiguities, deeply rooted historical rivalries, contested cultural heritage, and cyclical surges of nationalism. The border remains a flashpoint because both sides view control over these historic temples and territories not just as questions of sovereignty, but as inseparable from their national identities.

Until both countries reach a meaningful and mutually respected settlement—or agree on credible international arbitration—flare-ups, unfortunately, are likely to persist.