During the time that the Khmer Rouge ruled Cambodia, the Vietnamese government became enemies with Pol Pot’s Cambodia largely because of the split in support of different communist regimes: Cambodia supported China, and Vietnam supported the Soviet Union. Cambodia created the Kampuchean National United Front for Salvation to fight the Khmer Rouge as well. The Kampuchean National United Front for Salvation fought alongside the Vietnamese to bring about a swift end to the Khmer Rouge regime. Afterwards, Cambodia became the People's Republic of Kampuchea. The remaining members of the Khmer Rouge then escaped to Thailand to seek refuge. Countries in the United Nations responded by either giving aid to Cambodians, who were experiencing famine within their own country, or by declaring that the invasion of Cambodia by Vietnam was a violation of Cambodia’s sovereignty. 

After the Vietnamese invaded Cambodia in late 1978, Cambodians began fleeing the conflict and the unfolding famine that accompanied it, and many of them ended up in refugee camps that sprang up along the Thai-Cambodia border.  Cambodian refugees sometimes lived for years in these camps, as they had no other place to go; only a fraction of Cambodian refugees were able to resettle abroad. The displacement of hundreds of thousands of Cambodians became a matter of international concern, as many of the displaced Cambodians who ended up in Thailand were even further dislocated after the Vietnamese invasion. While Cambodians were initially welcomed in Thailand, because the political situation in Cambodia remained unstable for nearly a decade, the Thai government was eventually forced to reconsider their intake of displaced people.  Many Cambodians died on the dangerous journey back to Cambodia.  Eventually, Vietnamese forces withdrew in 1989, and a new Cambodian government was created. Only then were those still displaced able to be repatriated, and the crisis came to an end.