(Photo by davecito via Flickr/CC BY 2.0 DEED)
For more than a century, Thailand and Cambodia have been at odds over their 817-kilometre land border and the maps that indicate it. At the start of June 2025, the border disputes escalated violently after the killing of a Cambodian soldier at one of their contested areas.
Later in June, Cambodia’s most influential politician, Hun Sen, leaked a private conversation with the Thai Prime Minister, Paetongtarn Shinawatra, in which Shinawatra criticized the Thai army—Thailand’s dominant power—and its actions in the ongoing border disputes. The Thai PM’s remarks sparked public anger against her fragile government, and more dangerously, these events have led to a rise in anti-Cambodian nationalist sentiment in Thailand.
On one hand, the prolonged conflict shows the fragility of mainland Southeast Asian politics. Thailand, despite having a civilian-led government, has its policies under the army’s firm influence. Similarly, Hun Sen holds great influence over Cambodia’s politics, distracting his citizens from the dark reality of domestic and regional issues.
On the other hand, there is another layer of power underneath the century-long border disputes. Amid Western colonizers’ 20th-century fight for power in the region, the 1904 Treaty between France and Siam (modern-day Thailand) is the root cause of the current border disputes. An ambiguous map led to decades of violence between the two neighbours.
While the 20th-century colonial power struggle has ended, the 21st-century great power rivalry between the U.S. and China is once again hiding itself behind Thailand and Cambodia’s strained relations. How can peace be achieved with nationalism on the rise and foreign interests creeping in?
Why Do Maps Matter in This Conflict?
In the late 19th century, Colonial France decided to expand their Southeast Asian territory into Laos. Siam (modern-day Thailand) strongly opposed this decision. The British Empire, in order to maintain trade with Siam and protect its interests in the region, supported Siam against the expansion of French forces. The competition among colonial powers for regional influence led to violent wars.
Finally, in the late 19th and early 20th centuries, Britain and France came into an agreement. They decided to turn Siam into a buffer or neutral state between the two imperial powers. The countries negotiated multiple Franco-Siamese treaties to establish borders between Siam and French Indochina (present-day Cambodia and Laos).
However, contradictory maps led to differing interpretations of the exact borders. Most notably, the ambiguity over the ownership of the Preah Vihear Temple. While the 1904 treaty used the natural line of the Dângrêk Mountains to divide, leaving the temple’s ownership undecided, later maps used by French surveyors placed it within Cambodian territory.
The use of geographical features in defining borders reflects the colonial powers’ priorities. Rather than comprehensive considerations of culture, languages, or historical impacts, administrative convenience was the primary consideration for the French Empire. This lack of localized considerations has led to violence. For instance, Thailand’s borders with Laos, also a result of colonial policies, remain peaceful due to having no significant historical or cultural sites. On the other hand, Thailand and Cambodia fought endlessly over the Preah Vihear Temple and other areas.
Maps as Colonial Legacies
Maps are visual representations of geographical areas. However, during their development, maps are subject to human biases and manipulation, the strongest force among which was from colonial powers.
In the 19th and 20th centuries, managing colonized lands required precision. It was important to illustrate locations of natural resources, coastal details, and land divisions for better understanding, trade, and exploitation. Pre-colonial maps primarily depicted practical destinations for merchants, but colonialism significantly altered the development of mapping. Cartographers designed the maps we see today to serve the needs of colonial control.
While maps appear to be scientific, they have always been and will continue to be vulnerable to power relations. John Brian Harley, the co-editor of The History of Cartography, argued in his essay that maps are not always what mappers claim them to be, objective and accurate. One should not interpret maps without their historical contexts and underlying power dynamics. These power factors can be the purpose of a map, its targeted audience, or its claim of territory ownership. All are important nuances behind a seemingly descriptive tool. Maps tell stories, many of which are stories of unjust practices.
The Power of Maps
Maps not only tell stories, but they also plant a powerful and sometimes imaginary seed in the minds of the seers. First, maps tell us who should be superior. For instance, 17th-century Chinese maps depict the country at the centre of the globe, reflecting the belief that their empire is the Middle Kingdom or the centre of the world. Another example is the Imperial Federation Map of 1886, which boldly states the glory of the British Empire. Mappers depicted British lands in pink-red, separating their territories and the people within them from the ‘Other,’ a simple indicator of power in a vivid, visual form.
Secondly, maps ‘inform’ the superior of their ‘subjects’ and/or territory control. For example, colonial maps divided Africa for the colonizers’ political purpose of controlling and exploiting it. The continent was arbitrarily cut up based on its cultural groups and languages, resulting in political and socio-economic instability in the region even now. Furthermore, although less well-known, is how the British Empire mass-produced maps of Africa to enforce a sense of ownership in its citizens. Mapping is a language of control.
Ultimately, despite their potential for distortion, maps remain crucial to claims of territorial ownership within the current international law system. In border disputes between two or more countries, maps are always the first point of contention. Historical maps can provide evidence of a country’s meaningful engagement with a specific territory.
Countries can also argue that the use of certain maps, especially those established by an international agreement, authority, or organization, can establish ownership of the land. In this case, the International Court of Justice ruled in 1962 that the Preah Vihear Temple—one of the main points of conflict due to its historical and cultural value—is within Cambodia’s territory. The case centred on whether the Temple belonged to Cambodia, as per the Franco-Siam map, and whether Thailand had acknowledged the use of this map.
The Court ultimately ruled in Cambodia’s favour. However, Thailand originally refused to involve the ICJ in the case and has recently continued to reject the ruling. It raises an important point: besides asking who has control over the design and production of maps, we must also ask who gets to say which map is valid?
Nationalism and Colonialism
Border disputes between Thailand and Cambodia have led to long legal proceedings and, no less significantly, triggered nationalism. The Thai nationalist force, with their infamous yellow shirts, has rejected any government’s reconciliation and cooperative efforts with Cambodia. At the same time, Hun Sen has publicly adopted nationalist rhetoric calling for “national unity” against Thailand’s aggression.
Nationalism in many Southeast Asia countries takes root in a collective memory of colonialism, imperialism, and foreign intervention. Even Thailand, one of the few countries that has never been a colony, was caught in the crossfire of colonial power competition.
The country faced serious threats to its independence in the 19th century as Britain and France fought for control of colonies. It rose above the pressure but only after a territorial compromise, such as the Franco-Siamese Treaties of the 19th and 20th centuries. Cambodia, similarly, is highly conscious of its territorial ownership after gaining independence from French colonial power. Pride, fear, and collective wounds from the colonial era are all too powerful.
The People
Maps, despite being human-made (or human-manipulated), play a huge role in shaping an individual’s national identity. As a child, one can only experience one’s immediate sociocultural surroundings. A map would be one of the first indicators that suggest there is something larger than yourself. Something that is not exactly you, but you are a part of a larger community, even when it’s only imagined.
Therefore, maps, nationalism, and collective memories of colonialism are deeply intertwined. They have given strength to the people during times like the Southeast Asia independence movement in the 20th century. But these forces also push people into great violence, like the ongoing conflict between Thailand and Cambodia. In the end, it is the people, regardless of their nationalities, who are most vulnerable to state-level conflict.
Taking Ownership
Thailand-Cambodia disputes go back to the competition for influence and resources between past colonial powers. While the 20th-century colonial era has passed, the region now faces the threat of another great power competition between China and the United States.
China now wishes to step into the Thailand-Cambodia conflict as a ‘neutral’ party. Yet, in the past years, the country’s intentionally close relationship with Cambodia, including its military support, has reignited colonial pride and fear in Thailand. This worsened the nationalist rhetoric in the country. While China can act as a third party, one should not forget its interest in expanding influence in mainland Southeast Asia. Without recognizing the risk of being controlled by another great power competition, Thailand and Cambodia will only get into more violence.
Dashed lines on drawings made by and for foreign interests have resulted in decades of public anger and violence. Current situations are even more ambiguous as domestic actors intentionally destabilize for their own interests. Amidst the grey area of national identity, past wounds, and violence, it is important to stay alert to the underlying power dynamics. A vision for a country should be human-centred and not map-based.
The future of Southeast Asian countries must be owned and decided by the people who live in them, not by any historical and political decisions of foreign actors.
Edited by Gustavo Villela
