The Cambodian War 1978-1991

Incidents along the border of Kampuchea (now Cambodia) and Vietnam began in May 1975, shortly after their respective wartime victories over the Cambodian and South Vietnamese regimes. During 1976, these incidents decreased – during a time a struggle for power among the Kampuchean leadership. However, the attacks escalated again after internal dissent had been eliminated in 1977. Kampuchea initiated similar incidents along its borders with Laos and Thailand; in Thailand, for example, 56 military and 117 civilians were killed in Kampuchean border probes during 1977. The most violent incidents, however, took place along the border with Vietnam. The Vietnamese government by then sought to replace the Khmer Communist Party leadership of Pol Pot with Khmer who were sympathetic to Vietnam but Kampuchean party purges eliminated this possibility. Kampuchean attacks beginning on September 24, 1977, resulted in as many as 1,000 Vietnamese civilian deaths and Vietnam responded with a punitive expedition into Kampuchea on December 26, 1977. The Khmer defenders proved more resilient than expected but Vietnam achieved its limited objectives and withdrew its troops on January 6, 1978. Unable to unseat the Kampuchean regime by other means Vietnam then turned to organizing a guerrilla war but this plan was abandoned and an invasion of Kampuchea began on November 18, 1978. About 10,000 Vietnamese troops crossed the border in a limited but successful diversionary offensive which failed to draw Khmer forces from the intended main axis of the Vietnamese invasion.

About December 25, 1978, Vietnam followed up its initial success by committing 100,000 troops, with 18,000 troops of the Vietnamese sponsored National Front for the National Salvation of Kampuchea (NFNSK) in support, to the overthrow of the Kampuchean government. The Khmer Rouge leadership decided to abandon the capital city, Phnom Penh, and it fell to Vietnamese forces about January 8, 1979. Within days, the leadership of the NFNSK announced the formation of the People’s Republic of Kampuchea (PRK) and a new government. Meanwhile, Vietnamese forces advanced to the Thai border and fanned out to occupy the rest of the country. The Khmer Rouge loyalists retreated to remote areas of the country and eventually into the refugee camps on the Thai side of the border, determined to keep fighting a guerrilla war against the new government and the Vietnamese. Their effectiveness was demonstrated by the Vietnamese commitment of an additional 50,000 troops in February 1979 to fight what was now a counter-insurgency war. During the course of the year, two new non-communist guerrilla armies also formed: the Khmer People’s National Liberation Armed Forces (KPNLAF) and the Sihanouk National Army (ANS).

China and the United States refused to accept the results of Vietnamese aggression nor would they recognize the PRK or its government, choosing to provide legitimacy to the overthrown Khmer Rouge government despite irrefutable evidence of its mass murdering conduct. The war continued at a significantly reduced level in 1980 as guerrilla attacks on the Vietnamese were mostly limited to the Thai frontier. Vietnamese forces raided the insurgent bases in Thailand, sometimes killing Thai soldiers. In 1982, the KPNLAF, ANS and Khmer Rouge created a united military front to oust the Vietnamese from Kampuchea while also agreeing to the formation of a coalition government-in-exile (including the Khmer Rouge) which gained United Nations (UN) recognition. Meanwhile, Vietnam launched an aggressive pacification campaign in 1984 along the Kampuchean-Thai border. Vietnamese construction of a barrier along the border began in 1985, using forced labor, and it was completed in 1987. The massive effort proved to have little effect on guerrilla movements to and from the Kampuchean interior and the insurgency continued unabated. By now, Vietnam had already committed to a complete and unconditional withdrawal from Kampuchea by 1990. The leaders of the PRK government and the government-in-exile met several times between 1987 and 1988 but failed to reach any agreement. The Khmer Rouge tried to hold territory during this period but failed. In 1989, the PRK government renamed the country Cambodia, its former name. Vietnam completed the withdrawal of its troops on September 25, 1989, leaving the Cambodian government to fight the insurgency on its own.

The Khmer Rouge did manage to gain control of parts of Cambodia after the Vietnamese withdrawal but failed to achieve a decisive victory and negotiations to end the war continued. In May 1991 the rival factions agreed to a cease-fire and a tentative plan for a coalition government. A final peace agreement, mediated by the UN, was signed in Paris on October 23, 1991, by the four Khmer factions (the tripartite Coalition Government of Democratic Kampuchea and the Cambodian government) and ministers of 19 other countries that participated in peace talks. Disarming of some of the factions then began under the UN Transitional Authority in Cambodia, which also aided in the return of 375,000 refugees along the border of Thailand. The tenuous peace between the rival factions was soon threatened by the refusal of the Khmer Rouge to disarm or cease expanding its territorial holdings.

Notes

[1] The classification of this war is disputed. Clodfelter lists it as the Vietnamese-Cambodian War; Correlates of War (CoW) divides the war into an inter-state war, followed by an extra-state war, ending with an intra-state war; Kohn lists it as Kampuchean Civil War.

[2] The initiation date of this war is disputed. Clodfelter lists it as 1977 and appears to favor December 26, 1977, the date of the Vietnamese punitive expedition. CoW dates the inter-state war as starting September 24, 1977 (because there was sustained combat after this date, but Vietnam pulled out in January 1978 and appeared to want to sponsor a guerrilla army instead); the extra-state war starts on January 8, 1979 (because the Vietnamese sponsored government took control then, even though this government lacked international recognition); the intra-state war starts on September 26, 1989 (because the Vietnamese troops had withdrawn, but support troops remained). Kohn is a bit ambiguous, stating the war began in late 1978 (probably when the main Vietnamese force invaded). It is important to note Vietnamese incursions like that in December 1977 had happened before (though not on that scale). The November 1978 invasion however was planned as a diversion for the invasion of December 1978 and, so, constitutes the beginning of sustained combat.

[3] Estimates of military/civilian battle deaths based on Clodfelter.

[4] Estimates of military battle deaths adjusted for differing start and end dates reported and rounded to the nearest thousand based on Clodfelter and CoW.

References

Brogan, 151-9; Cambodia - A Country Study; Clodfelter, 1142-4; COW189, 475; 854; Kohn, 255-6; Vietnam - A Country Study.

Category

Inter-State War^[1]

Region

East Asia

Belligerents

Cambodia, Vietnam, Khmer Rouge, ANS, KPNLAF

Dispute

Territory, Governance

Initiation Date

November 18, 1978^[2]

Termination Date

October 23, 1991

Duration

12 years, 11 months, 6 days
(4723 days)

Outcome

Negotiated Settlement
(UN mediation)

Fatalities

Total: 50,000/150,000^[3]
Cambodia: 22,000^[4]
Vietnam: 28,000^[4]

Magnitude

5.3