The Genocidal Regime and its Removal: A Closer Look at the Cambodian-Vietnamese War

Cambodian-Vietnamese War: Analyzing an Intervention Against Genocide

The invasion and occupation of Cambodia by Vietnam during the late 1970s and early 1980s remains a disputatious and complex chapter in the history of Southeast Asia. Driven by a mix of political, ideological, and strategic motivations, Vietnam's intervention aimed to throw out the genocidal Khmer Rouge regime and establish a pro-Vietnamese government in Cambodia.

The Genocidal Regime and its Removal: A Closer Look at the Cambodian-Vietnamese War
Vietnam - China War 1979

This article delves into the historical events surrounding Vietnam's invasion, the subsequent occupation, and the lasting implications it had on both countries and the wider region.

Understanding the Khmer Rouge: Ideology and Historical Context

The Khmer language, also called Cambodian, is spoken by the Khmer people and is the official language of Cambodia. From 1976 to 1989, Cambodia was called "Kampuchea." After the Khmer Rouge regime was overthrown and a new government was formed, the name changed back to "Cambodia."

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"Khmer" refers to the dominant ethnic group (approximately 90% of the total population) in Cambodia, known as the Khmer people. The Khmer are the largest ethnic group in Cambodia and make up the majority of the country's population.

"Rouge" is the French word for "red." In the context of the Khmer Rouge, it refers to the communist ideology embraced by the Khmer Rouge regime. The term "Khmer Rouge" was coined by foreign journalists during the time of their rule in Cambodia (1975-1979) and became widely used to refer to the Communist Party of Kampuchea, which was led by Pol Pot.

The name "Khmer Rouge" was not used by the regime itself but was adopted by the international community to describe the radical communist movement that came to power and implemented a radical social and political revolution in Cambodia during that period.

The Rise of the Khmer Rouge:

To understand Vietnam's invasion of Cambodia, it is crucial to examine the rise of the Khmer Rouge. Led by Pol Pot, the Khmer Rouge came to power in 1975 after overthrowing the U.S.-backed government of Lon Nol. Pol Pot and the Khmer Rouge were very cruel to the people of Cambodia. They were motivated by their extreme communist beliefs and wanted to create a perfect farming society in the country.

He was a Cambodian dictator with communist ideologies who led the Cambodian genocide, resulting in the deaths 1.5 to 2 million people, almost a quarter of Cambodia's population in 1975. This widespread extermination specifically targeted intellectuals, Christians, and other religious groups, as well as non-Khmer residents living in Cambodia. Under the Khmer Rouge regime, Cambodia experienced one of the most brutal genocides in modern history.

The Khmer Rouge was a communist political group that ruled Cambodia from 1975 to 1979. The Khmer Rouge aimed to transform Cambodia into a classless farming society based on their version of Marxist and Maoist ideologies. During their rule, the Khmer Rouge implemented radical and brutal policies that resulted in widespread human rights abuses, mass executions, forced labor, and other cruelty.

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One of the most notorious aspects of the Khmer Rouge's rule was the Cambodian Genocide. The Khmer Rouge's extreme social engineering and harsh policies led to a devastating impact on Cambodia, causing immense suffering and leaving lasting scratch on the country.

The regime was overthrown in 1979 by Vietnamese forces, leading to the end of the Khmer Rouge's rule. Later, Cambodia went through a long process of recovery and rebuilding. The Khmer Rouge's legacy remains a dark chapter in Cambodian history, and efforts have been made to seek justice for the crimes committed during that period.

Motivations for Vietnam's Intervention:

After the Khmer Rouge attacked Vietnam's border provinces, Vietnam took action by invading Cambodia in 1978 and removing the Khmer Rouge from power. Vietnam remained in Cambodia for ten years, but their occupation faced criticism from the international community and created numerous problems and challenges.

Vietnam's decision to invade Cambodia in December 1978 was driven by various factors. Firstly, there were security concerns as the Khmer Rouge launched cross-border attacks on Vietnamese border villages, resulting in civilian casualties. Secondly, Vietnam sought to remove the Khmer Rouge from power due to ideological differences and the inhumanity committed by the regime. Additionally, Vietnam aimed to install a pro-Vietnamese government in Cambodia to protect its strategic interests and counter the influence of China, which supported the Khmer Rouge.

It is important to note that Vietnam's invasion of Cambodia was not conducted unilaterally. Vietnam sought support from other nations within the region and the international community to legitimize its actions. The Soviet Union, a key ally of Vietnam, provided diplomatic cover and logistical support for the invasion.

Invasion and Overthrow of the Khmer Rouge:

Vietnam's invasion of Cambodia in 1979 marked a significant turning point in the country's history. The swift and successful military campaign resulted in the overthrow of the Khmer Rouge regime and the establishment of the People's Republic of Kampuchea (PRK) under Vietnamese influence. 

In the early morning of January 7, 1979, Vietnamese forces launched a full-scale invasion of Cambodia from the eastern border. Backed by tanks, artillery, and air support, they rapidly advanced, encountering little resistance from the demoralized and weakened Khmer Rouge forces. On January 8, just a day after the invasion began, Vietnamese troops reached Phnom Penh, the capital city.

The capture of Phnom Penh marked the end of the Khmer Rouge's brutal rule, which had caused immense suffering and death for the Cambodian population. Following the removal of the Khmer Rouge, a new government was formed with leaders from Cambodia who had left the Khmer Rouge group. Heng Samrin, who used to be a Khmer Rouge military officer, became the Chairman of the Council of State. Other people who left and disagreed with the Khmer Rouge became the main leaders of the PRK.

The Genocidal Regime and its Removal: A Closer Look at the Cambodian-Vietnamese War
Evolution of Cambodia's flag

The PRK government, though formally independent, was heavily reliant on Vietnam for political, economic, and military support. Vietnam maintained a significant military presence in Cambodia, with thousands of troops stationed across the country to ensure the stability and security of the new government. Vietnamese advisers and officials played key roles in various sectors of the PRK administration, including defense, education, and economic planning.

It is important to note that Vietnam's invasion and subsequent occupation of Cambodia were not universally condemned. Many Cambodians, especially those who had suffered under the Khmer Rouge regime, welcomed the overthrow of Pol Pot and the restoration of relative stability. For them, Vietnam's intervention offered hope for a better future and an end to the horrors of the past. 

Occupation and International Reactions:

The establishment of the PRK and Vietnam's role in the governing setup drew international criticism and accusations of Vietnamese occupation. The United Nations General Assembly passed resolutions condemning Vietnam's invasion and occupation of Cambodia, asserting the principles of national sovereignty and non-interference in the internal affairs of states.

Internally, the PRK faced challenges and resistance from remaining members of the Khmer Rouge and non-communist resistance groups. These factions, supported by external powers like China and the United States, continued to fight guerrilla warfare against the Vietnamese-backed government. The Khmer Rouge, although weakened, still controlled pockets of territory along the Thai-Cambodian border and retained international recognition as the legitimate government of Cambodia.

Vietnam's occupation of Cambodia lasted for over a decade until its withdrawal in September 1989, during which efforts were made to rebuild the country's infrastructure, restore social order, and pursue economic development. However, the occupation also fueled hostility among some Cambodians who viewed Vietnam as an occupying force and didn't like the interference in their country's affairs. Besides, international actors who questioned Vietnam's intentions and accused it of Neo-colonialism.

The international response to Vietnam's occupation was mixed. China, a strong supporter of the Khmer Rouge, condemned Vietnam's actions and launched military incursions into northern Vietnam. The United States, while disapproving of the Khmer Rouge, opposed Vietnam's occupation and supported non-communist resistance groups. In September 1989, Vietnam withdrew its troops from Cambodia in response to international pressure and to avoid getting involved in a prolonged conflict with local armed resistance groups.

The Genocidal Regime and its Removal: A Closer Look at the Cambodian-Vietnamese War
Map of Vietnam and Cambodia

Red Allies: Soviet Contributions in Vietnam's Defense Against China

In response to Vietnam's occupation of Cambodia, China launched military incursions into northern Vietnam that escalated tensions between the two nations. The conflict between China and Vietnam during this period, known as the Sino-Vietnamese War of 1979 (Feb 17, 1979 – Mar 16, 1979), resulted in border clashes, with both sides experiencing casualties. However, several factors contributed to China's decision to cease the war such as:

During the Sino-Vietnamese War, the Soviet Union provided substantial support to Vietnam, although it did not directly engage in military action. The Soviets played a crucial role in assisting Vietnam through the provision of intelligence, equipment, and logistical aid. The Soviet Union deployed a considerable number of military advisers to Vietnam. It is estimated that between 5,000 to 8,000 Soviet advisers were present in Vietnam in 1979, providing training and expertise to Vietnamese soldiers.

During the Sino-Vietnamese War, the Soviet Union demonstrated its support for Vietnam by deploying troops along the Sino-Soviet border and the Mongolian-Chinese border. This deployment served multiple purposes, including showcasing solidarity with Vietnam and acting as a difficulty to Chinese aggression. By tying up Chinese troops along these borders, the Soviets indirectly supported Vietnam's defense against China.

Moscow refrained from direct intervention during the Sino-Vietnamese War because Beijing had assured both Moscow and Washington that the invasion would be limited and Chinese forces would withdraw shortly. In response, Moscow adopted a "wait and see" approach, observing whether China would indeed restrict its offensive.

In the aftermath of the Sino-Vietnam War, both China and Vietnam assert claims of victory. During the conflict, Chinese troops briefly entered Vietnamese territory along the China-Vietnam border, but they subsequently withdrew. Vietnam maintained control over Cambodia until 1989. In response to the tensions, Vietnamese authorities increased the expulsion of overseas Chinese residents. The border clashes between China and Vietnam persisted until 1991, creating a prolonged period of contention between the two nations. As such, the question of who emerged as the definitive victor in the Sino-Vietnam War remains complex, with both sides maintaining their respective claims.

While border tensions persisted for several years, the war officially concluded with China's withdrawal, and both countries eventually normalized relations in the 1990s.

The Genocidal Regime and its Removal: A Closer Look at the Cambodian-Vietnamese War
Pol Pot with Chinese Communist leader Deng Xiaoping

Resolution and Withdrawal:

International pressure, economic difficulties, and the withdrawal of Soviet support prompted Vietnam to reconsider its occupation of Cambodia. In 1989, under the leadership of General Secretary Nguyen Van Linh, Vietnam started on a process of disengagement and initiated negotiations with various Cambodian factions and the international community.

The Paris Peace Accords, signed in 1991, paved the way for a political settlement in Cambodia. The United Nations Transitional Authority in Cambodia (UNTAC) was established to supervise the peace process and organize elections.

Legacy and Implications:

Vietnam's invasion and occupation of Cambodia had far-reaching implications for both countries and the region. On one hand, the intervention brought an end to the Khmer Rouge's reign of terror and helped rebuild Cambodia, laying the foundation for stability and development. On the other hand, Vietnam's actions faced criticism for violating Cambodia's sovereignty and fueling regional tensions.

The occupation affected Vietnam's relations with China and the United States, who viewed it as an attempt to extend Vietnamese influence and counter Chinese dominance in the region. It also cemented Vietnam's image as an occupying power in the eyes of some Cambodians and contributed to ongoing political divisions within Cambodia.

After the fall of the Khmer Rouge regime, efforts were made to establish a tribunal to prosecute those responsible for the crimes committed during that period. It took several decades for the international community and Cambodia to agree on the establishment of a special court to try the Khmer Rouge leaders.

The Extraordinary Chambers in the Courts of Cambodia (ECCC), commonly known as the Khmer Rouge Tribunal, was established in 2006 as a joint effort between the United Nations and the Cambodian government. The ECCC has the mandate to prosecute senior leaders and those most responsible for the crimes committed during the Khmer Rouge era.

The role of the Khmer Rouge tribunal, as identified by the Extraordinary Chambers, was to deliver justice to the Cambodian people who were victims of the Khmer Rouge regime's policies, which encompassed crimes against humanity, war crimes, and genocide committed between April 1975 and January 1979.

Several high-ranking Khmer Rouge officials were brought to trial before the tribunal, including Nuon Chea and Khieu Samphan, who were convicted of crimes against humanity, war crimes, and genocide. They were found guilty and sentenced to life imprisonment.


Vietnam's invasion and occupation of Cambodia during the late 1970s and early 1980s represented a complex and controversial period in Southeast Asian history. Motivated by security concerns, ideological differences, and strategic interests, Vietnam intervened to remove the genocidal Khmer Rouge regime and establish a pro-Vietnamese government.

The occupation faced international condemnation and strained regional relations, but it also brought an end to the Khmer Rouge's brutal rule and initiated the process of rebuilding Cambodia. The legacy of Vietnam's intervention continues to shape the political landscape of both Vietnam and Cambodia, while serving as a reminder of the complexities and challenges that arise when regional powers intervene in the affairs of neighboring nations.