The Khmer Rouge insurgency was an armed conflict in Cambodia and eastern border of Thailand that began in 1979 when the Khmer Rouge-ruled government of Democratic Kampuchea was deposed during the Cambodian–Vietnamese War. Between 1979 and the 1991 Paris Peace Agreements, the war was fought between the Vietnam-supported People's Republic of Kampuchea and an opposing coalition. After 1991, the unrecognized Khmer Rouge government and insurgent forces continued to fight against the new government of Cambodia from remote areas until their defeat in 1998. The remaining Khmer Rouge forces surrendered in 1999.
After the fall of the Khmer Rouge regime, Cambodia came under Vietnamese military occupation, and a pro-Hanoi, Soviet government known as the People's Republic of Kampuchea (PRK) was formed, led by the Kampuchean United Front for National Salvation. The conflict was fought during the 1980s between the People's Republic of Kampuchea and the Coalition Government of Democratic Kampuchea (CGDK). The latter was a government-in-exile formed in 1981 that was composed of three Cambodian political factions: the royalist FUNCINPEC party led by Prince Norodom Sihanouk, the Party of Democratic Kampuchea (often referred to as the Khmer Rouge), and the Khmer People's National Liberation Front (KPNLF). The Khmer Rouge representative at the UN, Thiounn Prasith, was maintained.
Throughout the 1980s, the CGDK, supported by China, Thailand, the United States, the United Kingdom, and others, continued to control significant territory and launch operations against Vietnamese forces and the PRK. Vietnam withdrew from Cambodia in 1989. Peace efforts intensified between 1989 and 1991, with two international conferences in Paris and a UN peacekeeping mission that helped maintain a ceasefire. The UN issued a mandate known as the United Nations Transitional Authority in Cambodia (APRONUC) to enforce a ceasefire and deal with the issue of refugees and disarmament.
In 1992, economic sanctions against Cambodia, imposed by the United States and its allies in 1975, were lifted. As part of the peace effort, UN-sponsored elections were held in 1993, which helped restore stability, and cement the gradual decline of the Khmer Rouge. However, a low-intensity conflict continued between the Cambodian army and Khmer Rouge guerrillas until 1998. Norodom Sihanouk was restored as the king of Cambodia in 1993, but the situation intensified following a coup in 1997. A coalition government formed after national elections in 1998, bringing political stability and leading to the surrender of the remaining Khmer Rouge forces that year.
The conflict
After the fall of the Khmer Rouge and the conflict with Vietnam, Cambodia's economic situation was disastrous. During the first six months of 1979, approximately 80,000 people fled from Cambodia to reach Thailand. Many refugees died as a result of anti-personnel mines while attempting to cross into Thailand, and many of those who did survive were turned away by Thai authorities. The refugees were forced into camps, especially in Preah Vihear province, where living conditions were precarious. Cambodia's food situation worsened further, with Vietnamese troops attacking during the rice harvest, and food stocks being looted by the two belligerent parties. From August 1979 onward, the exile of the Cambodians became truly cataclysmic. Over one million people driven by hunger moved to the Thai border. The Khmer Rouge also sent its worst-off troops to the refugee camps where humanitarian aid, which flowed to the camps through the Royal Thai Armed Forces, contributed to helping the Khmer Rouge troops get back on their feet.Ponchaud 2007, p. 99-103. After the first wave of refugees came to Thailand, between 100,000 and 300,000 civilians remained sheltered in camps on the Thai border, along a strip of around 30 kilometres. Anti-Vietnamese forces were supplied by China, primarily with small arms, through Thailand.Cesari, 1995, p. 269 At the international level, the entry of Vietnamese troops into Cambodia was condemned by most countries under pressure from China and the U.S., which wished to prevent Vietnam from establishing itself as a dominant power in Southeast Asia. The UN did not recognise the People's Republic of Kampuchea, and following a vote in November 1979, the body considered Democratic Kampuchea to be Cambodia's sole legitimate government.Ponchaud 2007, p. 93.
Starting in 1983, Margaret Thatcher's government sent elements of the British SAS, the Special Air Service, to train the Khmer Rouge in landmine technologies. The U.S. and UK also imposed an embargo on Cambodia, resulting in serious consequences for the economy.
Thailand, which had been accepting refugees, opened the Khao I Dang camp in Sa Kaeo province on 19 November 1979, about ten kilometres from Cambodia where 150,000 people would soon arrive. Thailand intended to recruit all Cambodian men of military age to form a force capable of repelling a possible Vietnamese attack. Around 250,000 other Cambodians preferred to stay in no-man's land between the two countries.
Prince Norodom Sihanouk, placed under house arrest by the Khmer Rouge in 1976, was taken from his palace during the Vietnamese offensive to be evacuated by plane to China. In the summer, an armed group favourable to the former monarch, the Movement for the National Liberation of Kampuchea (MOULINAKA), was founded on the border with Thailand to fight against the Vietnamese. Former corvette operations captain, Kong Siloah, led it until his death in August 1980. Different groups of the Khmer Serei, or "Free Khmers", that carried out guerrilla operations against the Khmer Rouge between 1975 and 1979, also organized themselves to fight the Vietnamese.
Son Sann, former prime minister of Sihanouk, brought together several Khmer Serei and soldiers who took refuge in the West to found the National Front for the Liberation of the Khmer People (KPNLF). In April 1979, it had around ten thousand refugees transported by the Thai army to the mountainous region of Sok Sann, opposite the province of Chanthaburi, which he declared a "liberated zone" and from where he launched appeals to his compatriots.Ponchaud 2007, p. 103-104
Son Sann contacted Norodom Sihanouk in January 1979 so that he could take over the leadership of his troops, but the prince refused on several occasions. In early 1981, Sihanouk created, with the support of ASEAN countries, an organization intended to lead anti-Vietnamese resistance, known as the National United Front for an Independent, Neutral, Peaceful, and Cooperative Cambodia (FUNCINPEC). Organized in March 1981, a group of his followers transported MOULINAKA troops to Khmer territory on the Thai border near the province of Surin. Former troops of Kong Siloah joined the prince's ten thousand supporters, with whom they founded the National Sihanoukist Army, which constituted the armed wing of FUNCINPEC.Ponchaud 2007, p. 104
During the summer of 1979, the Khmer Rouge took advantage of the monsoon that hampered the movement of Vietnamese troops to reorganize themselves to launch offensives, renaming their armed forces the National Army of Democratic Kampuchea. In July, Pol Pot installed his new headquarters, Bureau 131, under the flank of Mount Thom. The Khmer Rouge benefited from the assistance of Thai special forces, which ensured the training and recruitment of the Khmer armed forces. In 1979, Khieu Samphan assumed the leadership of a new body that took the place of the government in exile, the Front of the Grand National Democratic Patriotic Union of Kampuchea. Pol Pot was content with his more discreet role as commander of the armed forces and did not make any public appearances after 1980.Peschoux, 1992, p. 155
Three Cambodian resistance movements against the Vietnamese invasion coexisted from 1981 onward. This included the Khmer Rouge and its National Army of Democratic Kampuchea, led by Pol Pot and numbering 20 to 30,000 men, Son Sann's KPNLF with 10,000 men, and the Sihanoukist Nationalist Army with 6,000 men. Each of these three movements extended their power over some Cambodian refugee camps. The Sihanoukist guerrillas had no supply problems, but their poor performance in the field prevented them from extending their authority to a significant number of civilians. At first, Sihanoukist forces were practically non-existent. Prince Norodom Ranariddh, one of Sihanouk's sons, was installed in Bangkok as his father's special representative. He would be appointed commander-in-chief of the ANS, without any military qualifications. Ranariddh depended on the Khmer Rouge, whom he provided funds, and in return guaranteed the formation of the ANS. It was only gradually that the Sihanoukist National Army, like the FNLPK, distinguished itself by true feats of arms.Deron 2009, p. 229-230.
The Vietnamese occupation force numbered around 200,000 troops in 1981. They were also responsible for training the army of the People's Republic of Kampuchea, the People's Revolutionary Armed Forces of Kampuchea, which initially numbered around 30,000 men.Ponchaud 2007, p. 107. The U.S. gave the People's Republic of China a carte blanche on the Cambodian problem and continued to recognize Democratic Kampuchea as the government of Cambodia, mostly to mark its opposition to the USSR-supported Vietnamese occupation. The UK and U.S., through Thailand, supported the Khmer Rouge as well as other guerrilla movements against the Vietnamese. Under American leadership, the World Food Program provided approximately US$12 million in food to the Khmer Rouge through the Thai army.Kiernan 1998, p. 554-555. The USSR appeared to be quite overwhelmed by the situation in Cambodia. By supporting Vietnam, the Soviet military gained access to the ports on the Vietnamese coast. The Soviet government was not very active in Cambodia, since their attention was monopolized at the same time by the Euromissile crisis and the War in Afghanistan.Deron 2009, p. 227