Democratic Kampuchea and the border war, 1975-1978

H1 History - syllabus 8838, 2027

What this lesson teaches

  • I can judge which factors shaped the Second and Third Indochina Wars.

    Syllabus 8838, Theme III, Learning Outcomes. evaluate the factors that shaped the development of Cold War conflicts in Southeast Asia

Make a guess

After taking power in 1975, how do you think Pol Pot's Khmer Rouge regime treated its larger neighbour Vietnam?

  1. It kept quiet, because Vietnam's army was far stronger.
  2. It raided Vietnamese border villages and cut diplomatic ties.
  3. It relied on Vietnam for protection against China.
Show the answer

It raided Vietnamese border villages and cut diplomatic ties.

The regime was fiercely anti-Vietnamese. Raids from 1977 killed civilians, and it broke off relations on 31 December 1977.

The Khmer Rouge regime attacked Vietnamese border areas, and Vietnam decided to remove it.

In April 1975, the Khmer Rouge captured Phnom Penh and created Democratic Kampuchea under Pol Pot. They emptied the cities and forced people into rural labour. Around 1.7 million people died from execution, starvation and disease.

The regime was fiercely nationalist and anti-Vietnamese. It purged members suspected of links with Hanoi and launched raids into Vietnamese border provinces from 1977, killing civilians.

Vietnam responded with counter-attacks. On 31 December 1977, Democratic Kampuchea broke off diplomatic relations with Vietnam. Vietnam began training Cambodian exiles to form an alternative government.

American analysts at the time judged that the push came from Hanoi. In early 1978 it had decided to remove the last unfriendly regime in Indochina. Pol Pot's attacks hastened that decision.

Fall of Phnom Penh
April 1975.
Deaths under the Khmer Rouge
Around 1.7 million.
Relations broken
31 December 1977.

Real examples to use

Year Zero, April 1975

The Khmer Rouge emptied Phnom Penh and other cities within days, forcing people into rural labour.

Tay Ninh raids, September 1977

Khmer Rouge forces attacked Vietnamese border villages and killed hundreds of civilians.

Ba Chuc, April 1978

Khmer Rouge troops killed more than 3,000 villagers in An Giang province, hardening Hanoi's decision to act.

Worked example: Weighing local actors

How far was Pol Pot responsible for the war?

  1. Pol Pot: border raids and anti-Vietnamese purges provoked Hanoi.
  2. Hanoi: wanted a friendly Cambodia, as it had in Laos.
  3. Interaction: each side's aims made compromise unlikely.
  4. Judgement: Pol Pot provoked, but Hanoi decided to invade.

Watch out for this

Vietnam invaded Cambodia mainly to stop the genocide.

Vietnam later used the regime's crimes to justify the invasion, but its main aims were security and a friendly government in Phnom Penh.

Check your understanding

What provoked Vietnamese military action against Democratic Kampuchea?

  1. A Cambodian alliance with the USA
  2. A request from the UN
  3. Khmer Rouge raids into Vietnamese border provinces
Show the answer

Khmer Rouge raids into Vietnamese border provinces

Right. The border war escalated from 1977.

Sources and context

Background reading for this chapter.

  • A CIA assessment of the conflict

    Paraphrase of the key judgments of an Interagency Intelligence Memorandum, "Sino-Soviet Competition in Indochina", prepared in the CIA, 14 November 1978.

  • A State Department analysis of Vietnam's motives

    Paraphrase of a briefing memorandum from the Acting Director of the Bureau of Intelligence and Research to Secretary of State Vance, 8 January 1979, the day after Phnom Penh fell.

  • Thailand watches the Vietnamese advance

    Paraphrase of a telegram from the US embassy in Bangkok to the State Department, 4 January 1979.

  • China prepares to attack

    Paraphrase of the minutes of a US National Security Council meeting on the Sino-Vietnamese conflict, 16 February 1979.

  • Lee Kuan Yew writes to Carter

    Paraphrase of a letter from Singapore's Prime Minister Lee Kuan Yew to President Carter, 1 March 1979.

  • a Vietnamese diplomat explains the Soviet treaty, November 1978

    Extract from the US record of a meeting in New York, 30 November 1978, between US official Robert Oakley and the Vietnamese representative (named "Co" in the record) in talks on normalising US-Vietnamese relations, four weeks after Vietnam signed its treaty with the USSR. Secret. Foreign Relations of the United States, 1977-1980, volume XXII, document 33. A US government document in the public domain.

  • Deng Xiaoping briefs President Carter, 29 January 1979

    Extract from the US memorandum of conversation of a meeting between President Carter, Vice Premier Deng Xiaoping and their senior advisers, Washington, 29 January 1979, a month after Vietnam invaded Cambodia. Foreign Relations of the United States, 1977-1980, volume XIII, document 205. A US government document in the public domain.

  • Carter reports Deng's private message, 30 January 1979

    Extract from a US memorandum of conversation, Washington, 30 January 1979, in which President Carter reported to his advisers on his private talk with Deng Xiaoping. China attacked Vietnam on 17 February 1979. Foreign Relations of the United States, 1977-1980, volume XIII, document 207. A US government document in the public domain.

  • the UN General Assembly on Kampuchea, November 1979

    Extract from United Nations General Assembly Resolution 34/22, "The situation in Kampuchea", adopted at the 67th plenary meeting, 14 November 1979, on a draft sponsored by the ASEAN states. A UN record.

  • a cartoon about the conflict, 1979

    An original cartoon drawn for these notes in the style of a Southeast Asian newspaper cartoon of 1979, after the Vietnamese invasion of Cambodia and the Chinese attack on Vietnam. It is not a copy of a real cartoon.

The Wise Otter

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