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.
Worked example: Weighing local actors
How far was Pol Pot responsible for the war?
- Pol Pot: border raids and anti-Vietnamese purges provoked Hanoi.
- Hanoi: wanted a friendly Cambodia, as it had in Laos.
- Interaction: each side's aims made compromise unlikely.
- 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?
- Khmer Rouge raids into Vietnamese border provinces
- A Cambodian alliance with the USA
- A UN request