Pol Pot

=== Fall of Democratic Kampuchea ===
{{main|Cambodian–Vietnamese War}}

In December 1976, the Kampuchean Communist Party Central Committee's annual plenum proposed the country ready itself for the prospect of war with Vietnam.{{sfn|Short|2004|p=363}} Pol Pot believed that Vietnam was committed to expansionism and thus was a threat to Cambodian independence.{{sfn|Short|2004|p=376}} There were renewed border clashes between Cambodia and Vietnam in early 1977, continuing into April.{{sfn|Short|2004|p=372}} On 30 April, Cambodian units, backed by artillery fire, entered Vietnam and attacked a series of villages, killing several hundred Vietnamese civilians.{{sfn|Short|2004|p=372}} Vietnam responded by ordering its Air Force to bomb Cambodian border positions.{{sfn|Short|2004|p=372}} Several months later, the fighting resumed; in September, two divisions of the Cambodian Eastern Zone entered the [[Tay Ninh]] area of Vietnam, where they attacked several villages and slaughtered their inhabitants.{{sfnm|1a1=Chandler|1y=1992|1p=141|2a1=Short|2y=2004|2p=375}} That month, Pol Pot travelled to Beijing, and from there to North Korea, where Kim Il Sung spoke out against Vietnam in solidarity with the Khmer Rouge.{{sfnm|1a1=Chandler|1y=1992|1p=145|2a1=Short|2y=2004|2pp=375–77}}

[[File:TuolSlang4.jpg|thumb|left|Busts of Pol Pot were produced in anticipation of a [[cult of personality]] ultimately never realized. This example is displayed in the [[Tuol Sleng Genocide Museum]].]]

In December, Vietnam sent 50,000 troops over the border along a 100-mile stretch, penetrating 12 miles into Cambodia.{{sfnm|1a1=Chandler|1y=1992|1pp=150–51|2a1=Short|2y=2004|2p=377}} Cambodia then formally broke off diplomatic relations with Vietnam.{{sfnm|1a1=Chandler|1y=1992|1p=151|2a1=Short|2y=2004|2p=377}} Cambodian forces fought back against the invaders, who had withdrawn to Vietnam by 6 January 1978.{{sfn|Short|2004|p=378}} At this point, Pol Pot ordered Cambodia's military to take an aggressive, proactive stance, attacking Vietnamese troops before the latter had the chance to act.{{sfn|Short|2004|p=389}} In January and February 1978, the Cambodian Army launched raids on various Vietnamese villages.{{sfn|Chandler|1992|p=151}} The Vietnamese Politburo then concluded that it must not leave Pol Pot in power, but must remove him from power before the Cambodian military strengthened further.{{sfn|Short|2004|p=378}} In 1978, it established military training camps for Cambodian refugees in southern Vietnam, forming the nucleus of a future Cambodian regime.{{sfnm|1a1=Chandler|1y=1992|1p=152|2a1=Short|2y=2004|2p=379}} The Cambodian government also readied itself for war. Plans for a [[personality cult]] revolving around Pol Pot were drawn up, based on the [[Mao Zedong's cult of personality|Chinese]] and [[Kim Il-sung's cult of personality|North Korean models]], in the belief that such a cult would unify the population in wartime.{{sfnm|1a1=Chandler|1y=1992|1pp=157–58|2a1=Short|2y=2004|2p=361}} Large photographs of Pol Pot began to be placed in communal dining halls,{{sfn|Chandler|1992|p=157}} while oil paintings and busts of him were produced.{{sfn|Chandler|1992|p=158}} The cult was ultimately never implemented.{{sfn|Short|2004|p=361}}

The failure of Cambodian troops in the Eastern Zone to successfully resist the Vietnamese incursion made Pol Pot suspicious of their allegiances.{{sfn|Short|2004|pp=384–85}} He ordered a purge of the Eastern Zone, with over 400 CPK cadres from the area being sent to S-21.{{sfnm|1a1=Chandler|1y=1992|1p=155|2a1=Short|2y=2004|2p=385}} Aware that they would be killed on Pol Pot's orders, increasing numbers of Eastern Zone troops began rebelling against the Khmer Rouge government.{{sfn|Short|2004|p=386}} Pol Pot sent more troops into the Eastern Zone to defeat the rebels, ordering them to slaughter the inhabitants of any villages that were believed to be harbouring any rebel forces.{{sfn|Short|2004|p=386}} This suppression in the east was, according to Short, "the bloodiest single episode under Pol Pot's rule".{{sfn|Short|2004|p=386}} Fleeing the government troops, many leading rebels—including Zone deputy chiefs [[Heng Samrin]] and [[Pol Saroeun]]—made it into Vietnam, where they joined the anti-Pol Pot exile community.{{sfn|Short|2004|p=386}} By August 1978, Pol Pot could only consider Mok's forces in the south-west and Pauk's in the Central Zone as being reliable.{{sfn|Short|2004|p=387}}

Early in 1978, Pol Pot's government began trying to improve relations with various foreign countries, such as Thailand, to bolster its position against Vietnam.{{sfn|Short|2004|p=381}} Many other governments in Southeast Asia sympathised with Cambodia's situation, fearing the impact of Vietnamese expansionism and Soviet influence on their own countries.{{sfn|Short|2004|p=391}} Although supportive of the Cambodians, the Chinese government decided not to send its army into Cambodia, fearing that an all-out conflict with Vietnam could provoke a war with the Soviet Union.{{sfn|Short|2004|p=393}} Meanwhile, Vietnam was planning its full-scale invasion of Cambodia.{{sfn|Short|2004|p=390}} In December 1978, it formally launched the [[Kampuchean United Front for National Salvation|Khmer National United Front for National Salvation]] (KNUFNS), a group made up of Cambodian exiles which it hoped to install in place of the Khmer Rouge. Initially, KNUFNS was headed by Heng Samrin.{{sfn|Short|2004|pp=390, 393}} Fearing this Vietnamese threat, Pol Pot wrote an anti-Vietnamese tract titled the ''Black Paper''.{{sfn|Short|2004|p=387}}

In September 1978, Pol Pot began increasingly courting Sihanouk in the hope that the latter could prove a rallying point in support of the Khmer Rouge government.{{sfn|Short|2004|p=388}} That same month, Pol Pot flew to China to meet with Deng.{{sfn|Short|2004|pp=388–89}} Deng condemned Vietnamese aggression but suggested that the Khmer Rouge had precipitated the conflict by being too radical in its policies and by allowing Cambodian troops to behave anarchically along the border with Vietnam.{{sfn|Short|2004|p=389}} On returning to Cambodia, in October Pol Pot ordered the country's army to switch tactics, adopting a defensive strategy involving the heavy use of [[land mines]] to stop Vietnamese incursions. He also cautioned the army to avoid direct confrontations which would incur heavy losses and instead adopt guerrilla tactics.{{sfn|Short|2004|pp=389–90}} In November 1978, the CPK held its Fifth Congress. Here, Mok was appointed the third ranked figure in the government, behind Pol Pot and Nuon Chea.{{sfn|Short|2004|p=392}} Soon after the Congress, two senior government members—Vorn Vet and Kong Sophal—were arrested and sent to S-21. This precipitated another round of purges.{{sfn|Short|2004|p=392}}