Vietnam overthrew the Khmer Rouge in two weeks and installed a friendly government, starting a decade of occupation.
On 25 December 1978, Vietnamese forces invaded Democratic Kampuchea. Phnom Penh fell on 7 January 1979.
Vietnam installed the People's Republic of Kampuchea under Heng Samrin, a former Khmer Rouge commander who had fled to Vietnam. About 150,000 to 200,000 Vietnamese troops stayed to support it.
The Khmer Rouge retreated to the Thai border and fought a guerrilla war. Many countries, including ASEAN, condemned the invasion as a violation of sovereignty, even though the Khmer Rouge regime had committed mass atrocities.
The occupation became a central issue in Southeast Asia for the next decade. It tested the principle that states should not use force against their neighbours.
- Invasion
- 25 December 1978.
- Phnom Penh falls
- 7 January 1979.
- Vietnamese troops
- About 150,000-200,000 stayed in Cambodia.
Worked example: Sovereignty versus humanitarian outcome
Why did ASEAN condemn the invasion despite the Khmer Rouge's crimes?
- Principle: invading a neighbour broke the rule of non-interference.
- Precedent: if accepted, it could threaten other small states.
- Security: Thailand now faced Vietnamese troops on its border.
- Result: ASEAN led the diplomatic campaign against the occupation.
Watch out for this
Vietnam withdrew from Cambodia soon after removing Pol Pot.
Vietnamese troops stayed for about a decade, until September 1989.
Check your understanding
Who led the government installed by Vietnam in 1979?
- Heng Samrin
- Pol Pot
- Sihanouk