Cambodian coup of 1970

Last updated

Cambodian coup of 1970
Part of the Cambodian Civil War
Date18 March 1970

Successful coup

  • Norodom Sihanouk's government is overthrown by Lon Nol
Monarchy of Cambodia

Khmer National Armed Forces/Parliament of Cambodia

Supported by:

  • CIA (disputed)
Commanders and leaders
Norodom Sihanouk Lon Nol

The Cambodian coup of 1970 (Khmer : រដ្ឋប្រហារឆ្នាំ ១៩៧០) refers to the removal of the Cambodian Head of State, Prince Norodom Sihanouk, after a vote in the National Assembly on 18 March 1970. Emergency powers were subsequently invoked by the Prime Minister Lon Nol, who became effective head of state, and led ultimately to the proclamation of the Khmer Republic later that year. It is generally seen as a turning point in the Cambodian Civil War. No longer a monarchy, Cambodia was semi-officially called "État du Cambodge" (State of Cambodia) in the intervening six months after the coup, until the republic was proclaimed. [1]

Khmer or Cambodian is the language of the Khmer people and the official language of Cambodia. With approximately 16 million speakers, it is the second most widely spoken Austroasiatic language. Khmer has been influenced considerably by Sanskrit and Pali, especially in the royal and religious registers, through Hinduism and Buddhism. The more colloquial registers have influenced, and have been influenced by, Thai, Lao, Vietnamese, and Cham, all of which, due to geographical proximity and long-term cultural contact, form a sprachbund in peninsular Southeast Asia. It is also the earliest recorded and earliest written language of the Mon–Khmer family, predating Mon and by a significant margin Vietnamese, due to Old Khmer being the language of the historical empires of Chenla, Angkor and, presumably, their earlier predecessor state, Funan.

Cambodia Southeast Asian sovereign state

Cambodia, officially the Kingdom of Cambodia, is a country located in the southern portion of the Indochina peninsula in Southeast Asia. It is 181,035 square kilometres in area, bordered by Thailand to the northwest, Laos to the northeast, Vietnam to the east and the Gulf of Thailand to the southwest.

Norodom Sihanouk 20th-century King of Cambodia

Norodom Sihanouk was a Cambodian royal, politician, composer and filmmaker who was King of Cambodia from 24 April 1941 to 2 March 1955 and 24 September 1993 to 7 October 2004; both reigns ended in abdication. In Cambodia, he is also known as Samdech Euv. Until the early years of his rule, his family ruled over the French Protectorate of Cambodia.


It also marked the point at which Cambodia became substantially involved in the Vietnam War, as Lon Nol issued an ultimatum to North Vietnamese forces to leave Cambodia.

Vietnam War 1955–1975 conflict in Vietnam

The Vietnam War, also known as the Second Indochina War, and in Vietnam as the Resistance War Against America or simply the American War, was an undeclared war in Vietnam, Laos, and Cambodia from 1 November 1955 to the fall of Saigon on 30 April 1975. It was the second of the Indochina Wars and was officially fought between North Vietnam and South Vietnam. North Vietnam was supported by the Soviet Union, China, and other communist allies; South Vietnam was supported by the United States, South Korea, the Philippines, Australia, Thailand and other anti-communist allies. The war is considered a Cold War-era proxy war from some US perspectives. It lasted some 19 years with direct U.S. involvement ending in 1973 following the Paris Peace Accords, and included the Laotian Civil War and the Cambodian Civil War, resulting in all three countries becoming communist states in 1975.


Since independence from France in 1954, Cambodia had been led by Prince Norodom Sihanouk, whose Sangkum political movement had retained power after winning the 1955 parliamentary election. In 1963, Sihanouk had forced the National Assembly to approve a constitutional amendment that made him head of state with no fixed term of office. He had retained domestic power through a combination of political manipulation, intimidation, patronage, and careful balancing of left- and right-wing elements within his government; whilst placating the right with nationalist rhetoric, he appropriated much of the language of socialism to marginalize the Cambodian communist movement, whom he called the Khmers rouges ("Red Khmers").

The Sangkum Reastr Niyum, literally the "community of the common people", was a political organisation set up in 1955 by Prince Norodom Sihanouk of Cambodia. Though it described itself as a 'movement' rather than a political party, the Sangkum retained control of the government of Cambodia throughout the first administration of Sihanouk, from 1955 to 1970.

With the Second Indochina War escalating, Sihanouk's balancing act between left and right became harder to maintain. Cross-border smuggling of rice also began to have a serious effect on the Cambodian economy. [2] In the Cambodian elections of 1966, the usual Sangkum policy of having one candidate in each electoral district was abandoned; there was a huge swing to the right, especially as left-wing deputies had to compete directly with members of the traditional elite, who were able to use their local influence. [3] Although a few communists within the Sangkum – such as Hou Yuon and Khieu Samphan – chose to stand, most leftists were decisively defeated. Lon Nol, a rightist who had been a longstanding associate of Sihanouk, became Prime Minister.

Hou Yuon was a veteran of the communist movement in Cambodia. A member of the Communist Party of Kampuchea, also known as the Khmer Rouge, he served in several ministerial posts during the 1960s and 1970s.

Khieu Samphan Cambodian war criminal

Khieu Samphan is a former Cambodian communist politician who was the chairman of the state presidium of Democratic Kampuchea (Cambodia) from 1976 until 1979. As such, he served as Cambodia's head of state and was one of the most powerful officials in the Khmer Rouge movement, although Pol Pot remained the General Secretary in the party. Khieu Samphan is the second oldest living former Khmer Rouge leader, alongside Nuon Chea. On 7 August 2014, they were convicted and received life sentences for crimes against humanity during the Cambodian Genocide, and a further trial found him guilty of genocide in 2018.

By 1969, Lon Nol and the rightists were growing increasingly frustrated with Sihanouk. Although the basis for this was partly economic, political considerations were also involved. In particular, the nationalist and anti-communist sensibilities of Lon Nol and his associates meant that Sihanouk's policy of semi-toleration of Viet Cong and People's Army of Vietnam (PAVN) activity within Cambodian borders was unacceptable; Sihanouk, during his swing to the left in 1963–66, had negotiated a secret arrangement with Hanoi whereby in return for the guaranteed purchase of rice at inflated prices, the port of Sihanoukville was opened for weapons shipments to the Viet Cong. As well as the rightist nationalists, the liberal modernising elements within the Sangkum, headed by In Tam, had also become increasingly alienated by Sihanouk's autocratic style.

Viet Cong mass political organization in South Vietnam and Cambodia

The Việt Cộng, also known as the National Liberation Front, was a mass political organization in South Vietnam and Cambodia with its own army—the People's Liberation Armed Forces of South Vietnam (PLAF)—that fought against the United States and South Vietnamese governments during the Vietnam War, eventually emerging on the winning side. It had both guerrilla and regular army units, as well as a network of cadres who organized peasants in the territory it controlled. Many soldiers were recruited in South Vietnam, but others were attached to the People's Army of Vietnam (PAVN), the regular North Vietnamese army. During the war, communists and anti-war activists insisted the Việt Cộng was an insurgency indigenous to the South, while the U.S. and South Vietnamese governments portrayed the group as a tool of Hanoi. Although the terminology distinguishes northerners from the southerners, communist forces were under a single command structure set up in 1958.

Peoples Army of Vietnam Combined military forces of Vietnam

The People's Army of Vietnam, also known as the Vietnamese People's Army (VPA), is the military force of the Socialist Republic of Vietnam. The PAVN is a part of the Vietnam People's Armed Forces and includes: Ground Force, Navy, Air Force, Border Defence Force, and Coast Guard. However, Vietnam does not have a separate Ground Force or Army branch. All ground troops, army corps, military districts and specialised arms belong to the Ministry of Defence, directly under the command of the Central Military Commission, the Minister of Defence, and the General Staff of the Vietnam People's Army. The military flag of the PAVN is the flag of the Socialist Republic of Vietnam, with the words Quyết thắng added in yellow at the top left.

Hanoi Municipality in Hà Nội, Vietnam

Hanoi is Vietnam's capital and second largest city by population. The city mostly lies on the right bank of the Red River. Hanoi is 1,720 km (1,070 mi) north of Ho Chi Minh City and 105 km (65 mi) west of Haiphong.

There is evidence that during 1969 Lon Nol approached the US military establishment to gauge military support for any action against Sihanouk. [4] Lon Nol's appointee as deputy Prime Minister, Prince Sisowath Sirik Matak – a US-friendly nationalist and leader of the Cambodian business community – is thought to have suggested that Sihanouk should be assassinated, though Lon Nol rejected this plan as "criminal insanity". [5] Sihanouk himself thought that Sirik Matak (who he characterised as a jealous rival claimant to the Cambodian throne) backed by the U.S. Central Intelligence Agency (CIA), and in contact with exiled Sihanouk opponent Son Ngoc Thanh, had suggested the coup plan to Lon Nol in 1969. [6] CIA involvement in the coup plot remains unproven, and Henry Kissinger later claimed that events would take the US government by surprise, but it seems likely that at least some military intelligence agents were partly culpable. [7]

Sisowath Sirik Matak Cambodian prince

Sisowath Sirik Matak was a member of the Cambodian royal family, under the House of Sisowath.

Central Intelligence Agency National intelligence agency of the United States

The Central Intelligence Agency (CIA) is a civilian foreign intelligence service of the federal government of the United States, tasked with gathering, processing, and analyzing national security information from around the world, primarily through the use of human intelligence (HUMINT). As one of the principal members of the United States Intelligence Community (IC), the CIA reports to the Director of National Intelligence and is primarily focused on providing intelligence for the President and Cabinet of the United States.

Son Ngoc Thanh was a Cambodian nationalist and republican politician, with a long history as a rebel and a government minister.

Declassified documents indicate that, as late as March 1970, the Nixon administration was hoping to garner "friendly relations" with Sihanouk.[ citation needed ]

Overthrow of Sihanouk

In March 1970, while Sihanouk was touring Europe, the Soviet Union and China, large-scale anti-Vietnamese demonstrations erupted in Phnom Penh. Crowds attacked the North Vietnamese and Viet Cong embassies. Sihanouk initially gave a certain degree of support to the demonstrators; he hoped Moscow and Beijing would pressure North Vietnam to reduce its presence in Cambodia. Indeed, it has even been suggested (by William Shawcross and others) that Sihanouk and Lon Nol may have planned the first demonstrations to gain political leverage against Hanoi.

The riots, however, escalated beyond the government's control – although this was likely done with a degree of encouragement from Lon Nol and Sirik Matak – and the embassy was sacked. Inside, a "contingency plan" was allegedly found for the communists to occupy Cambodia. On 12 March, Sirik Matak cancelled Sihanouk's trade agreement with North Vietnam; Lon Nol closed the port of Sihanoukville to the North Vietnamese and issued an impossible ultimatum to them: all PAVN and Viet Cong forces were to withdraw from Cambodian soil within 72 hours (on 15 March) or face military action. [8] When, by the morning of 16 March, it was clear that this demand had not been met, some 30,000 youths gathered outside the National Assembly in Phnom Penh to protest against the Vietnamese presence.

From this point, events were to move with increasing rapidity. On the same day, the Cambodian Secretary of State for Defence, Colonel Oum Mannorine (Sihanouk's brother-in-law), was scheduled to be questioned by the national legislature on allegations of corruption; the proceedings were adjourned to hear the demonstrators' resolutions. According to Sihanouk, Mannorine had received information that Lon Nol and Sirik Matak were about to precipitate a coup; a group of Mannorine's men, under the command of Phnom Penh's Chief of Police Major Buor Horl, attempted to arrest the plotters, but it was by then too late. [9] Mannorine, and other key security personnel loyal to Sihanouk, were placed under arrest. After the Assembly adjourned for the day, Sihanouk's mother Queen Kossamak, at Sihanouk's request, summoned Lon Nol and Sirik Matak to the Royal Palace and asked them to end the demonstrations. [10]

It appears to have been sometime during 16 or 17 March that Sirik Matak finally swayed Lon Nol to remove Sihanouk from the government. Lon Nol, who until that point may have been merely hoping that Sihanouk would end his relations with North Vietnam, showed some reluctance to take action against the Head of State: to convince him, Sirik Matak allegedly played him a tape-recorded press conference from Paris, in which Sihanouk threatened to execute them both on his return to Phnom Penh. [11] However, the Prime Minister remained uncertain, with the result that Sirik Matak, accompanied by three army officers, finally compelled a weeping Lon Nol to sign the necessary documents at gunpoint.

The next day – 18 March – the army took up positions around the capital, and a debate was held within the National Assembly under In Tam's direction. One member of the Assembly (Kim Phon, later to be killed by pro-Sihanouk demonstrators in Kampong Cham) walked out of the proceedings in protest, though was not harmed at the time. The rest of the assembly voted unanimously to invoke Article 122 of the Cambodian constitution, which withdrew confidence in Sihanouk. Lon Nol took over the powers of the Head of State on an emergency basis, while the position itself was taken by the President of the General Assembly, Cheng Heng. In Tam was confirmed as President of the Sangkum. The coup had, therefore, followed essentially constitutional forms rather than being a blatant military takeover. [12] These events marked the foundation of the Khmer Republic.

Queen Kossamak was forced to leave the royal palace by the new government and held in house arrest in a villa in the suburb before being allowed to join her son in Beijing in China for health reasons in 1973 and died there two years later.

Demonstrations against the coup

On 23 March, Sihanouk (via Beijing Radio) called for a general uprising against Lon Nol. Large-scale popular demonstrations calling for Sihanouk's return began in Kompong Cham, Takéo Province, and Kampot Province. [13] The demonstrations in Kompong Cham became particularly violent, with two National Assembly deputies, Sos Saoun and Kim Phon, being killed by demonstrators on 26 March after driving to the town to negotiate. Lon Nol's brother, police official Lon Nil, was set upon in the nearby town of Tonle Bet by plantation workers and was also killed.

The demonstrations were suppressed with extreme brutality by the Cambodian army; there were several hundred deaths and thousands of arrests. Some witnesses spoke of tanks being used against crowds of unarmed civilians. [13]


Following the coup, North Vietnam forces invaded Cambodia in 1970 at the request of Khmer Rouge leader Nuon Chea. Thousands of Vietnamese were killed by Lon Nol's anti-communist forces and their bodies dumped in the Mekong River. [14] Attacks against Vietnamese began after a demand by Lon Nol that all Vietnamese communists leave Cambodia. [15] [16] Phnom Penh's North Vietnamese embassy was ravaged by Cambodians. [17] [18] [19] Of the approximately 450,000 Vietnamese in Cambodia, 100,000 left the country and another 200,000 were forcibly repatriated to South Vietnam, reducing the estimated population of ethnic Vietnamese to 140,000 just five months after the coup. [16] These events marked the start of the Cambodian Civil War pitting Lon Nol's regime backed by US air power against the Khmer Rouge and North Vietnam. Lon Nol fled Cambodia in 1975 right before the Khmer Rouge's seizure of power.

See also

Related Research Articles

Lon Nol Cambodian Field Marshal

Marshal Lon Nol was a Cambodian politician and general who served as Prime Minister twice, as well as serving repeatedly as Defense Minister. He led the military coup of 1970 against Prince Norodom Sihanouk and became the self-proclaimed President of the U.S.-backed Khmer Republic, ruling until 1975. He was the founder and leader of the short-lived Social Republican Party, and commander-in-chief of the Khmer National Armed Forces. After the Khmer Rouge took power, Lon Nol fled to the United States, and remained there until his death in 1985.

Khmer Republic former country

The Khmer Republic was the pro–United States military-led republican government of Cambodia that was formally declared on 9 October 1970. Politically, the Khmer Republic was headed by General Lon Nol and Prince Sisowath Sirik Matak that took power in the 18 March 1970 coup against Prince Norodom Sihanouk, then the country's head of state.

Kingdom of Cambodia (1953–1970) 1953-1970 monarchy in Southeast Asia

The Kingdom of Cambodia, informally known as the first Kingdom of Cambodia and the Sangkum Reastr Niyum era, referred to Norodom Sihanouk's first administration of Cambodia from 1953 to 1970, an especially significant time in the country's history. Sihanouk continues to be one of the most controversial figures in Southeast Asia's turbulent and often tragic postwar history.

Cambodian Civil War civil war in Cambodia between 1970 and 1975

The Cambodian Civil War was a military conflict that pitted the forces of the Communist Party of Kampuchea and their allies the Democratic Republic of Vietnam and the Viet Cong against the government forces of the Kingdom of Cambodia and, after October 1970, the Khmer Republic, which were supported by the United States (U.S.) and the Republic of Vietnam.

In Tam Prime Minister of Cambodia

In Tam was a former Prime Minister of Cambodia. He served in that position from May 6, 1973 to December 9, 1973, and had a long career in Cambodian politics.

Lon Non was a Cambodian politician and soldier who rose to his greatest prominence during the Khmer Republic (1970–1975).

The Social Republican Party or Socio-Republican Party was a political party in Cambodia, founded by the then Head of State Lon Nol in June 1972 to contest the National Assembly Elections of the Khmer Republic held on September 3, 1972.

Cambodia–Vietnam relations Diplomatic relations between the Kingdom of Cambodia and the Socialist Republic of Viet Nam

Cambodia–Vietnam relations take place in the form of bilateral relations between the Kingdom of Cambodia and the Socialist Republic of Vietnam. The countries have shared a land border for the last 1,000 years and share more recent historical links through being part of the French colonial empire. Both countries are members of the Association of Southeast Asian Nations (ASEAN).

Cheng Heng was a Cambodian politician, who acted as the country's Head of State from 1970–1971, and was a relatively prominent political figure during the Khmer Republic period (1970–1975).

The Royal Government of the National Union of Kampuchea was a government-in-exile of Cambodia, based in Beijing, that was in existence between 1970 and 1976, and was briefly in control of the country starting in 1975.

The Krom Pracheachon, often referred to simply as Pracheachon, was a Cambodian political party that contested in parliamentary elections in 1955, 1958 and 1972.

The Samlaut Uprising, otherwise called the Samlaut Rebellion or Battambang Revolts, consists of two significant phases of revolts that first broke out near Samlaut in Battambang Province and subsequently spread into surrounding Provinces in Cambodia during 1967-1968.The revolutionary movement was largely made up by the dissident rural peasantry led by a group of discontented leftist intellectuals against Prince Norodom Sihanouk’s political organization –the Sangkum regime.

Saloth Chhay was a Cambodian left-wing journalist and political activist, who was prominent in the country's politics during the 1950s, 1960s and 1970s. He is best known for being the older brother of Pol Pot, future leader of the Khmer Rouge communists, and for influencing his early political development.

The Cambodian Republican Party was a short-lived political movement established during the Khmer Republic period (1970–75).

Khmer Renovation, also translated as "Khmer Renewal", was an anti-communist, nationalist and royalist political party founded in Cambodia in September 1947. In 1955, it became one of the core elements of the Sangkum political movement of Prince Norodom Sihanouk.

The following lists events that happened during 1975 in Cambodia.


  1. The name "State of Cambodia" would be later revived under the People's Republic of Kampuchea regime between 1989 and 1993. Soizick Crochet, Le Cambodge, Karthala, Paris 1997, ISBN   2-86537-722-9
  2. Kiernan, B. How Pol Pot came to power, Yale UP, p.228
  3. Kiernan, p.232
  4. Kiernan, p.300
  5. Kiernan, p.301
  6. Sihanouk, pp.36–38
  7. Clymer, K. J. The United States and Cambodia, Routledge, 2004, p.22
  8. Sutsakhan, Lt. Gen. S. The Khmer Republic at War and the Final Collapse Washington DC: United States Army Center of Military History, 1987, Part 1, p. 42. See also Part 1 Part 2 Part 3.
  9. Sihanouk, p.50
  10. Ayres, D. Anatomy of a Crisis, University of Hawaii Press, 2000, p.71
  11. Marlay, R. and Neher, C. Patriots and tyrants, Rowman & Littlefield, 1999, p.165
  12. Clymer, p.21
  13. 1 2 Kiernan, p.302
  14. Ben Kiernan (2008). Blood and Soil: Modern Genocide 1500–2000. Melbourne Univ. Publishing. pp. 548–. ISBN   978-0-522-85477-0.
  15. Colin Mackerras (2 September 2003). Ethnicity in Asia. Routledge. pp. 197–. ISBN   1-134-51516-2.
  16. 1 2 Christopher R. Duncan (2004). Civilizing the Margins: Southeast Asian Government Policies for the Development of Minorities. Cornell University Press. pp. 247–. ISBN   0-8014-4175-7.
  17. Spencer C. Tucker (20 May 2011). The Encyclopedia of the Vietnam War: A Political, Social, and Military History, 2nd Edition [4 volumes]: A Political, Social, and Military History. ABC-CLIO. pp. 1756–. ISBN   978-1-85109-961-0.
  18. Chileng Pa; Carol A. Mortland (12 February 2008). Escaping the Khmer Rouge: A Cambodian Memoir. McFarland. pp. –. ISBN   978-1-4766-2828-8.
  19. Brig. Gen. Tran Dinh Tho (6 November 2015). Cambodian Incursion. Normanby Press. pp. –. ISBN   978-1-78625-457-3.