Historical Overview
Colonial Era
French colonizers who first came to Cambodia in the early 1860s encountered a rich culture and history dating back to the ninth century. The colonizers were initially welcomed by Cambodian King Nordom Suramarit. The king thought French forces would help protect Cambodia from its neighbors, namely the Vietnamese and Siam who were vying for control over Cambodian territory. Ultimately, France did stop the fighting, however, France’s protection cost Cambodians dearly. By 1884 France demanded absolute control over Cambodia, forcing the Cambodian king’s cooperation at gun point. In response Cambodians, led by Buddhist Monks among others, led an uprising (1885-87). Cambodians fought back against unfair taxation and foreign influence, but ultimately it was their own king who quelled the uprising. While the king had first been duped by the French into thinking he would have control over the country, he too pulled a sleight of hand on his subjects to regain his own power. To maintain his title and position, he convinced the resisters to back down. In turn he made sure that the Cambodians most involved in fighting for Cambodian freedom were removed from politics and positions of influence. Cambodia thus emerged weaker and the king stronger.
In 1941, the French removed the king from power and replaced him with his 18-year-old son, Prince Nordom Sihanouk. The prince, born in 1922, was the eldest son of King Suramarit and Queen Sisowath Kossamak. Despite his prestigious education in French schools in Saigon and Paris, the French thought that in crowning Sihanouk they could more easily manipulate Cambodia society.
The French, however, underestimated Prince Sihanouk’s political ambitions and skills, both of which he used to negotiate France’s departure after World War II. France finally gave up its colony in 1953, nearly 100 years after they first seized it. When they departed, the colonial forces returned power to the prince. Prince Sihanouk’s ability to rule, however, was challenged when a civil war erupted in neighboring Vietnam in 1955 and the violence spilled across its borders.
Angkor Wat
Angkor Wat, among Cambodia's most famous tourist attractions and a UNESCO World Heritage site, demonstrates the long history of the Khmer people. Built in the early twelfth century, it was intended to represent the mythical Mount Meru. By the time the French occupiers arrived, the temple had been abandoned for 600 years.
Buddhism
Archeological findings indicate Buddhism was present in Cambodia since the fifth century CE. Ian Harris' extensive research on Cambodian Buddhism explains that it is challenging to determine with certainty Cambodia' Buddhist origins and influences. Overall, it is important to note that Cambodia' Buddhist history is intertwined with the region's historical developments, cultural adaptions, and political changes. It is more than "just" a religion.
Cold War Context and Vietnam War
The Vietnam War (1955-1975) pitted the communist government of North Vietnam against South Vietnam and its democratic ally, the United States. Cambodia, which shares a 700-mile border with Vietnam, was pulled into the conflict. At first, Prince Sihanouk preferred a neutral stance to the Vietnam war and tried to stay out of it. However, this proved impossible when South Vietnam, guided by the US, started to pressure Cambodia to take their side and allow them to build military bases in Cambodia. Prince Sihanouk’s ability to stay neutral ended in 1963, when he outright rejected an offer for US aid. His decision was informed, at least in part, by the US’s tactical involvement and organization of a political coup against South Vietnamese President Ngo Dinh Diem (November 1-2, 1963), which resulted in the president and his brother Ngo Dinh Nhu’s assassination. In response, Prince Sihanouk spoke out against western democracies and voiced support for communist ideology. Given his family’s experience with French colonization and war, this position does not seem irrational. But his alignment with communism, in the context of Cold War politics, put a target on his back. Sihanouk’s rejection of US aid had a profound impact on Cambodia’s economy and without US money, his army deteriorated. This in turn helped foster a right-wing rebellion against Sihanouk within his now underfunded military.
In 1970, while the war in Vietnam continued, the US-backed a military coup to oust Prince Sihanouk. While Prince Sihanouk was away on a trip to Moscow and Beijing, senior military leader and the sitting prime minister Lieutenant-General Lon Nol successfully launched a coup d’état and took power. Prince Sihanouk’s followers, intent on reclaiming power, fled the presidential palace and joined forces with the budding communist Khmer Rouge guerilla movement hiding deep in Cambodia’s jungles. Sihanouk vowed to fight the new Khmer Republic, which was used in turn by the Khmer Rouge as a cover to recruit followers.
US President Richard Nixon, 1970
On April 30, 1970, US President Nixon, in a television broadcast, relays the 'importance' of bombing sites in Cambodia to flush out Vietnamese communists. Despite this public rationalization, in realty this decision had dire consequences for Cambodian civilians caught in the crossfire. In total, between 1969 and 1973, more than half a million tons (1 billion pounds) of munitions descended on rural Cambodia. In 1973 alone, the US dropped a quarter of a million tons of bombs on Cambodia in just 6 months. This was one-and-a-half times as many explosives unleashed on Japan during the whole of the Second World War.
Norodom Sihanouk
Norodom Sihanouk was the King and longtime political leader of Cambodia who played a central role in the country’s turbulent 20th-century history. He led Cambodia to independence from France in 1953 and alternated between roles as king, prime minister, and head of state over several decades. His shifting alliances—with the West, communists, and monarchists—reflected his efforts to preserve Cambodian sovereignty amid regional and global conflicts, especially during the Vietnam War and Khmer Rouge era.
Khmer Rouge
The Khmer Rouge (French for “Red Khmer”) formed in 1960. Its leader Pol Pot (born Saloth Sar) was an avid admirer of Maoist communism and envisioned repeating Mao Zedong’s attempt to convert China’s economy into a socialist society through industrialization and collectivization (the so-called Great Leap Forward) in Cambodia. Ten years after it formed, the Khmer Rouge guerillas attacked the U.S.-backed Lon Nol government that had overthrown Prince Sihanouk. Pol Pot and his followers viewed Lon Nol as pro-Western and thus anti-Communist and wanted to eradicate all traces of Western influence from Cambodian society.
Cambodian Civil War
From 1970 to 1975 Cambodia was locked in a brutal civil war between two groups with very different political beliefs. On one side, called the Khmer Rouge, was a communist group supported by the Soviet Union and China and led by Pol Pot. The other side, the Khmer Republic, was led by Lon Nol and supported by the US and other Western countries. Both sides harmed and murdered civilians. By 1973, most of the country was controlled by the Khmer Rouge except for the capital city of Phnom Penh and a few provinces. Some 2 million Cambodians had fled to the capital to escape the violence caused by the civil war and US bombing along the Cambodian and Vietnam border.
In 1975 the Khmer Rouge succeeded in overthrowing the Lon Nol government and within days of doing so launched a program to institute Mao’s communist agenda in China in Cambodia. The result was devastating violence and genocide.
Genocide
During the three-year, eight month, and 20 days of Khmer Rouge rule, some 2 million people perished, meaning that in less than four years the Khmer Rouge’s violent policies resulted in the death of one quarter of Cambodia’s total population. It is estimated that up to 40 percent of those deaths were the result of starvation and disease.
All Cambodians suffered under the Khmer Rouge, but certain groups were systematically targeted. These groups included ethnic minorities (including Chinese and Vietnamese), religious groups (including Buddhist monks and Cham Muslims), and social groups (those considered wealthy and/or educated).
Raphael Lemkin
Raphael Lemkin, a Jewish Polish lawyer and Holocaust survivor, coined the term "genocide" in 1944. A truncated version of Lemkin's definition formed the basis of the United Nations 1948 Convention on the Prevention and Punishment of the Grime of Genocide.
Genocide Definition
Article II of the UN Genocide Convention narrowly defines victims as those intentionally targeted for destruction owing to their ethnic, racial, religious, or national identity. The majority of victims during the Cambodian Genocide sit outside this narrow formulation of victimhood, but were victims all the same. When studying communist genocides, it serves us well to consider how victimization expands according to communist ideology.
Cambodia after Genocide
When Vietnamese forces finally ousted the Khmer Rouge from power in 1979, the country was in utter shambles—nearly all professionals, engineers, technicians, doctors, veterinarians, and teachers had been murdered making it that much more difficult to rebuild. The Vietnamese forces, upon capturing the capital Phnom Penh, set up a transitional government composed of Khmer Rouge defectors. Meanwhile, the leaders of the Khmer Rouge had retreated into the jungle along the Thai border and there regrouped and relaunched guerrilla attacks against the Vietnamese and their Cambodian allies. The Chinese government lent its support to the Khmer Rouge rebels and renewed fighting forced tens of thousands of Cambodians to flee into neighboring countries. By the time the military conflicts concluded in 1989, an additional 14,000 Cambodian civilians perished. The country’s first democratic elections were held in 1993.
Trials
As the 1990s progressed, the Khmer Rouge political movement declined and by 1997 the Cambodian government requested support from the United Nations to prosecute the former leaders of the Khmer Rouge. At this point, Pol Pot was still alive, and pressure mounted for his arrest. Pol Pot had fled Phenom Penh before the Vietnamese forces arrived in 1979.
The creation of a hybrid Cambodian-United Nations tribunal, however, proved incredibly difficult and expensive. In 2001, the Cambodian government passed a law to bring the Extraordinary Chambers in the Courts of Cambodia (ECCC) into being. And in June 2003, the UN and Cambodia signed an agreement to create the tribunal. The court elected to only try the highest-ranking members of the Khmer Rouge. By the time the trials were finally opened in 2009, Pol Pot and many other of the most notorious leaders of the Khmer Rouge were dead or deemed unable to stand trial.
Investigations and court proceedings occured from 2006 and 2022. During this time, 10 individuals were named and investigated, 3 of whom were convicted (Khieui Samphan, Nuon Chea and KaingGuek Eav). Since it was established in 1997, the ECCC has incurred a total cost of $330 million.
References:
Elizabeth Becker. When the War Was Over: Cambodia and the Khmer Rouge Revolution (New York: Public Affairs, 1998).
David Chandler. A History of Cambodia (New York: Routledge, 2018).
Documentation Center of Cambodia (DC‑Cam). Documentation Center of Cambodia. Accessed October 7, 2025. https://www.dccam.org
Ian Harris. Cambodian Buddhism: History and Practice (University of Hawaii Press, 2008).
Ben Kiernan. How Pol Pot Came to Power: Colonialism, Nationalism, and Communism in Cambodia, 1930-1975 (New Haven, CT: Yale University Press, 2004).
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