Cambodian Genocide 1975-1979: Khmer Rouge and the Killing Fields

The Cambodian genocide was the mass killing and death of Cambodians under the Khmer Rouge, the communist movement that ruled the country, which it renamed Democratic Kampuchea, from April 1975 to January 1979. Led by Pol Pot, the regime emptied the cities, abolished money, religion and private life, and drove the population into forced labour on rural communes. An estimated 1.5 to 2 million people, around a fifth of the population, died from execution, starvation, disease and overwork.

Background

Cambodia became independent from France in 1953 under Prince Norodom Sihanouk, who tried to keep the country neutral during the Vietnam War. North Vietnamese forces nonetheless used Cambodian territory for supply routes and bases, and from 1969 the United States secretly bombed them there.

In March 1970 General Lon Nol overthrew Sihanouk and established the Khmer Republic, aligned with the United States. American and South Vietnamese troops entered Cambodia in the Cambodian Campaign of 1970. Sihanouk, in exile in Beijing, lent his name and popularity to an alliance with the Khmer Rouge, until then a small rebel movement.

A brutal civil war followed. American bombing, which continued until August 1973, killed many civilians and drove refugees into the cities; historians disagree about how much it helped Khmer Rouge recruitment. Phnom Penh swelled to perhaps 2 million people as the Khmer Rouge closed in.

The fall of Phnom Penh and the evacuation

On 17 April 1975, two weeks before the fall of Saigon, Khmer Rouge soldiers entered Phnom Penh. Within hours they ordered the entire population to leave, claiming that the Americans were about to bomb the city and that people could return in a few days. Hospital patients, the elderly and children were forced onto the roads in the heat. Other towns were emptied in the same way.

The new rulers declared a fresh start that foreign writers later called “Year Zero”. The regime abolished money, markets, private property, schools, books and religion. Buddhist monks were forced to leave the monasteries, and families were often separated. The country was run in secret by “Angkar”, “the organisation”, whose leaders remained largely anonymous until 1977.

The Khmer Rouge leaders drew on Maoist ideas of peasant revolution and on China’s Great Leap Forward, but went further than any other communist state. They aimed at total self-reliance and a society without classes, cities or foreign influence. A secret Four-Year Plan drafted in 1976 demanded harvests of three tonnes of rice per hectare across the country, far more than Cambodian farming had ever produced, while rice was exported to China in exchange for weapons and equipment.

Life under Democratic Kampuchea

The population was divided into “base people”, rural dwellers who had lived in Khmer Rouge zones, and “new people”, the city evacuees regarded as enemies. New people received less food and were watched closely. Everyone worked long days in rice fields and on irrigation schemes, many of them badly designed, to meet impossible production targets.

Food was rationed and communal eating was imposed. Foraging for food could be punished as a crime. Medicine was scarce, and trained doctors had often been killed or hidden their past. Malnutrition, malaria and exhaustion killed hundreds of thousands of people.

Mass killing and the security system

The regime hunted “enemies” from the start. Officials and soldiers of the Lon Nol government were among the first killed. Teachers, professionals and anyone associated with foreign contact were also at risk, though the idea that wearing glasses alone meant death is a later simplification.

Ethnic and religious minorities suffered terribly. The Vietnamese minority was expelled or killed, and the Cham Muslim and Chinese communities lost a very large share of their members. From 1976 the party turned on itself, and purges swept through the regional administrations, above all the Eastern Zone in 1978.

The regime operated a network of around 200 prisons. The most notorious was S-21, a former school in Phnom Penh known as Tuol Sleng, run by Kang Kek Iew, known as Duch. At least 14,000 people were held there, photographed, tortured into confessions and then killed, many at Choeung Ek outside the city. Only a handful are known to have survived. Researchers have identified around 20,000 mass grave pits across the country.

Little of this was clear to the outside world at the time. The country was sealed off, and only a few foreign visitors were allowed in on guided tours. Refugees who reached Thailand described the killings, and the French priest François Ponchaud published one of the first detailed accounts, “Cambodia: Year Zero”, in 1977. Some Western commentators nevertheless doubted the reports until Vietnam’s invasion opened the country to journalists and investigators in 1979.

War with Vietnam and the fall of the regime

Despite their earlier alliance, the Khmer Rouge and communist Vietnam became bitter enemies. From 1977 Khmer Rouge forces raided Vietnamese border villages, killing civilians; at Ba Chuc in April 1978 several thousand villagers were massacred. Vietnam sheltered Khmer Rouge defectors, among them Hun Sen and Heng Samrin.

On 25 December 1978 Vietnam invaded Cambodia with well over 100,000 troops. Phnom Penh fell on 7 January 1979 and the People’s Republic of Kampuchea was proclaimed under Heng Samrin. In February China, the Khmer Rouge’s main backer, attacked northern Vietnam in a short border war.

Key people

Pol Pot (1925–1998), born Saloth Sar, studied in Paris in the early 1950s and became secretary of the Communist Party of Kampuchea. Known as “Brother Number One”, he was prime minister of Democratic Kampuchea. He died in April 1998 in the Khmer Rouge’s last stronghold at Anlong Veng.

Nuon Chea (1926–2019), “Brother Number Two”, was the party’s chief ideologist. Khieu Samphan (born 1931) was head of state. Ieng Sary (1925–2013) was foreign minister, and his wife Ieng Thirith (1932–2015) was minister of social affairs; she was found unfit to stand trial because of dementia. Ta Mok (c. 1926–2006), a military commander known for brutal purges, died in custody before he could be tried.

Kang Kek Iew (1942–2020), known as Duch, ran the S-21 prison and later converted to Christianity. He was the first Khmer Rouge leader convicted by the UN-backed court.

Consequences

Cambodia emerged from the regime traumatised and impoverished, and famine threatened in 1979–80. Hundreds of thousands of people fled to camps on the Thai border. A generation of teachers, doctors and other educated Cambodians had been lost, and many survivors suffered lasting trauma, which slowed the country’s recovery for decades. Because the new government was installed by Vietnam, a Soviet ally, China, the United States and most Western and Southeast Asian states continued to recognise a coalition including the Khmer Rouge as Cambodia’s representative at the United Nations throughout the 1980s.

Vietnam withdrew its troops in 1989. The Paris Peace Agreements of October 1991 led to a UN transitional administration and elections in 1993. The Khmer Rouge fought on until its movement collapsed in 1998–99.

In 2006 the Extraordinary Chambers in the Courts of Cambodia began work. Duch was convicted in 2010 and sentenced on appeal to life imprisonment in 2012. Nuon Chea and Khieu Samphan were convicted of crimes against humanity in 2014 and of genocide against the Cham and Vietnamese in 2018. The Tuol Sleng Genocide Museum and Choeung Ek memorial are now visited by many Cambodians and foreigners.

Myths and facts

Myth: almost all victims were executed. Executions killed hundreds of thousands, but a very large share of deaths came from hunger, disease and overwork caused by the regime’s policies.

Myth: the court found genocide against all Cambodians. The tribunal’s genocide convictions concerned the Cham and Vietnamese minorities. The killing of Khmer people was judged as crimes against humanity, although “Cambodian genocide” is the usual name for the whole period.

Fact: the term “killing fields” comes from a survivor. The phrase was popularised by the Cambodian journalist Dith Pran and by the 1984 film “The Killing Fields”, based on his experiences.

By the numbers

Timeline

• 1970, 18 March: Lon Nol overthrows Prince Sihanouk.
• 1975, 17 April: The Khmer Rouge capture Phnom Penh and evacuate the city.
• 1976, January: A constitution proclaims Democratic Kampuchea.
• 1977, September: Pol Pot publicly reveals the existence of the Communist Party of Kampuchea.
• 1978, April: Khmer Rouge troops massacre villagers at Ba Chuc in Vietnam.
• 1978, 25 December: Vietnam invades Cambodia.
• 1979, 7 January: Phnom Penh falls to Vietnamese forces.
• 1998, 15 April: Pol Pot dies near the Thai border.
• 2018, 16 November: Nuon Chea and Khieu Samphan are convicted of genocide.

Why it matters

The Khmer Rouge regime stands among the most lethal of the 20th century in proportion to population. It shows the consequences of an ideology that sought to rebuild society from zero through total control. The decades-long struggle for recognition and trials also made Cambodia a key case in the development of international criminal justice.