Historical Context of Hun Sen's Escape to Vietnam in June 1977

On the night of 20 June 1977, the twenty-five-year-old Hun Sen, who was Regiment Commander in Region 21 of the DK's Eastern Zone, and his four confidants—Nhek Hourn, Nuch Than, San Sanh and Var Po Ean—left their military post in Koh Thmor village, Memot district, Tbong Khmum province (Cambodia) with a risky plan to cross Cambodia's eastern border to seek Vietnamese support to build a resistance front against Pol Pot's genocidal regime (Baphnom 2016: 5). As Hun Sen recalled, after clearing their path through a nearly 200-meter stretch of a minefield on the Cambodian side of the border, he and his comrades, fortunately, evaded the patrol of the Vietnamese border defence forces. At 2:00 am on 21 June 1977, they reached the Vietnamese side of the border unharmed (Baphnom 2016: 5).Footnote ² Forty years later, this event became commemorated as Hun Sen's heroic journey, dubbed Marching Towards National Salvation, which is the title of the 90-minute documentary film widely released to the public since early 2018. To his critics, the film marks “an escalation of Hun Sen's myth-making efforts,” to increase his popularity after the dissolution of the country's only viable opposition, the Cambodian National Rescue Party (Handley and Niem Reference Handley and Niem2018). Specifically, although such a representation revealed the concerted efforts of the ruling Cambodian People's Party (CPP) under Hun Sen's leadership to seal his legacy, it erroneously obscured the history of Hun Sen's escape to Vietnam in June 1977 and how it impacted his early rise to power. Yet, making this event a unique and linear historical episode erred by omitting historical contingencies and landscape of this particularly significant event.

Pol Pot's Purging Campaigns 1972–77

In the 1960s, no one would have expected that the Cambodian revolution would become one of the most brutal regimes in the twentieth century. Pol Pot's youth was more or less uneventful. When he returned to Cambodia after losing the state scholarship due to his political agitation, Pol Pot and his clique took an opportunity to take over the weakened and disintegrated leftist party of Cambodia, the Khmer People's Revolutionary Party (KPRP), after the Sihanouk regime's harsh repression during the 1955–1960 period (Mosyakov Reference Mosyakov2001: 36–38). With the concessions that communist China and the Soviet Union made to the West during the 1954 Geneva Conference, the Khmer communist representatives, unlike the Vietnamese and Lao communists, were not admitted to the conference, and they were given two choices: (1) lay down their arms and participate in the national elections organized by the Sihanouk regime in 1955 or (2) go to North Vietnam with the withdrawing Viet Minh forces. According to historian Ben Kiernan, between 1954–55 as many as 2000 (out of approximately 3500 Khmer communists) fled to North Vietnam to take shelter from the repression of Prince Sihanouk's authority (Kiernan 1982: 174–75), whereas others refused to leave Cambodia and stayed behind to continue their revolutionary activities underground and without external support (Mosyakov Reference Mosyakov2001: 38). During this time, Pol Pot also changed the name of the party to the Communist Party of Kampuchea (CPK) because he thought the KPRP was too close to the Indochina Communist Party (ICP) and Vietnam.

The year 1970 was a watershed moment. The coup led by Lon Nol and Prince Sisowath Sirik Matak plunged the country into a civil war. Prince Sihanouk called on his people to take up arms, and so they did to bring him back to power. The 1970 coup was indeed a boon for the KR communists. For instance, when there was a call for unity of the resistance movement, the KR would appear as the natural torchbearer. The KR's quick rise in strength came from the amalgamation of other groups of malcontents with the new republican regime that still supported Prince Sihanouk. They answered his call to join the “Marquis” and took up arms. Soon, it became clear that the KR communists considered Prince Sihanouk to be anti-revolutionary and carefully indoctrinated the party cadres to that effect (Ith Sarin Reference Ith2002). Prince Sihanouk, in turn, was also aware of this treachery and repeatedly showed his intention to resign from the movement (Chanda Reference Chanda1986: 66–73). Such a move would doom the movement, and the KR communists had to concede by allowing the prince to visit the liberated areas in 1972.

The frictions continued well into the later stage of the struggle. On 2 April 1974, to dispel their Chinese patron's concern about the lack of unity between the Sihanoukists and the KR, Saloth Sar (Pol Pot), Nuon Chea and Son Sen, who headed the National Military Committee in charge of directing domestic military operations, sent the CPK representatives, Ieng Sary and Khieu Samphan, to assure Chairman Mao Zedong and Premier Zhou Enlai of their unity with Prince Sihanouk to defeat the Lon Nol regime (Lu Reference Lu2018). In private, Pol Pot and his loyalists did not welcome this development because of Prince Sihanouk's popularity and desire to form a Sihanouk-style socialist regime, i.e. moderate, Buddhist and monarchist (Cixous Reference Cixous1985: 120). Even before Pol Pot took over the country in 1975, he made sure that those people who answered Prince Sihanouk's call, but who were not close to him, began to quietly disappear one by one.

After 1970, most of the cadres in the KR leadership structure were the left-wing intellectuals who supported Prince Sihanouk or were in his government. In a rare account by an outsider, Ith Sarin, who had gone to live with the KR in 1972, the tension between the Pol Pot faction and the Sihanouk faction trickled down to the lower level (Ith Sarin Reference Ith2002). Another observation that he made was the tension between the KR, the People's Army of Viet Nam (PAVN) and the Liberation Armed Forces of Southern Vietnam, which was the armed wing of the National Front for the Liberation of Southern Vietnam (NLF)—better known as the ‘Viet Cong’—who remained in Cambodia until late 1973 (Path Reference Path2020: 56–67). Accordingly, the Vietnamese communist delegation's September 1974 visit to the KR leadership in Cambodia's territory was met with a cold reception by their Cambodian host (Nguyen 2014: 241–45). The pro-Sihanouk and pro-Vietnamese threats set the stage for Pol Pot's purges during the early 1970s well before Pol Pot came to power in April 1975.

Besides the Sihanoukist group, the Khmer communists who fled to North Vietnam and were trained by the Vietnamese communists posed a greater threat to the Pol Pot clique; for them, any Khmer revolutionary associated with the Vietnamese could be a Vietnamese spy. It was against this backdrop and combined with his existing suspicion and paranoia regarding the ‘burrowing Vietnamese spies’ that Pol Pot began to carry out the purge of anyone or any group that was not handpicked by him (Bou Reference Bou2011; Colm Reference Colm1996; Nem Reference Nem2009).Footnote ³ It suffices here to point out several cases where Pol Pot's purges led to a number of key KR communist leaders, including Bou Thang, Seuy Keo, Say Pouthang, Hun Sen, Chea Sim and Heng Samrin fleeing to Vietnam between 1975–78, and they returned to become top leaders of the PRK in 1979.

As early as 1972, Pol Pot began purging the Hanoi-trained Khmer communists (the so-called ‘Khmer Hanoi’) from positions of authority, and most were executed; they were accused of being ‘revisionists’ and subjected to ‘study sessions,’ meaning thought reform (Chandler Reference Chandler1999, 95–96). Pol Pot's purging campaign was escalated in 1973 after the Vietnamese communists withdrew from Cambodia (Chandler Reference Chandler1999: 95–96).

In the Northeast Zone, similar purges occurred. Units composed of indigenous tribes of the region were also targets of the purge. Pol Pot was intolerable for any units that had a connection with Son Ngoc Minh, a former member of the ICP, who was thought to be unreliable due to his link with the Vietnamese. The purge also pushed many indigenous people into Vietnam even before 1975 (Bou Reference Bou2011). In Rise of the Brao: Ethnic Minorities in Northeastern Cambodia during Vietnamese Occupation, Ian Baird estimated that about 100 Khmer Hanoi from the Ratanakiri province of Cambodia travelled to North Vietnam in 1954. Among those who made the trip to Hanoi were two young men named Bou Thang (ethnic Tampuon man from Kachoan village in Voeunsai) and Seuy Keo, who was a teenage friend of Bou Thang's and lived in the nearby ethnic Kachok village. Both joined the communist revolution in 1954; Bou Thang and Seuy Keo both received advanced military training in Vietnam (Baird Reference Baird2020: 63–93). On 1 May 1970, after the northeast of Cambodia had been ‘liberated’ by the KR, the two veterans along with many other Khmer Hanoi started the long journey along the Ho Chi Minh Trail by foot from North Vietnam to Cambodia. Both became KR military high-ranking leaders in the newly liberated Northeastern Zone. Yet, Pol Pot and other Khmer communists loyal to him harboured deep distrust towards the Khmer Hanoi. Following the first group of the Brao minority fleeing to Vietnam in November 1973, the Pol Pot faction escalated purges of the Khmer Hanoi, and Bou Thang, Seuy Keo and most of the Brao fled to Vietnam in early 1975 (Baird Reference Baird2020: 63–93). In Region 11 in the Southwest Zone, Koh Kong province, Say Phouthong and local guerillas joined the anti-Pol Pot movement out of dissatisfaction with the local authority. Around 1974, as Pol Pot started to consolidate power, Koh Kong was put to the sword. Many commanders were called up for a ‘meeting’ and never returned, and those who survived had to escape to Thailand (Nem Reference Nem2009).

After 1975, the future targets of the purge were people close to Pol Pot, and those who were in command of major political-military centres of DK. As the DK conflict with Vietnam intensified, Pol Pot escalated his purges of real and perceived ‘Vietnamese agents’ from the Party Centre (division level of the military) to the provincial authority. He said the following to Chinese Premier Hua Guofeng in their meeting on 29 September 1977:

In 1977, Pol Pot's systematic campaign to purge perceived and real ‘Vietnamese agents’ in the Eastern Zone intensified. Towards the end of 1976, the Pol Pot regime carried out the phase of deepening and widening its socialist revolution as it prepared for a military confrontation with its number one enemy, Vietnam, in the east. All sectors, especially the armed forces, were instructed to prioritize political tasks to uproot the remnants of the enemies burrowing from within, especially those who belonged to the category of ‘Khmer bodies with Vietnamese mind,’ referring to pro-Vietnamese elements in society (Path and Kanavou Reference Path and Angeliki2015: 320). As mentioned above, Pol Pot proudly told Chinese Premier Hua Guofeng in September 1977 that he had successfully rid the army and party of all ‘Vietnamese agents.’

Among the purged DK top officials, no case was more dramatic than the story of So Phim, the commander of the Eastern Zone bordered with Vietnam. Phim was the superior of all military units in the zone, including the regiment commanded by the young Hun Sen. The purge occurred against the backdrop of a short-lived KR incursion into Vietnam and the devastating Vietnamese counterattack in 1977. Because of Phim's close working relationship with the Vietnamese, Pol Pot suspected that Phim's Eastern Zone became a sanctuary of Vietnamese spies and those ‘Khmer bodies with Vietnamese mind,’ and the Vietnamese successful counterattacks in early 1977 deepened Pol Pot's distrust towards Phim.

Phim was a veteran of the KPRP and later a high-ranking member of Pol Pot's CPK. When Phim was called to Phnom Penh amidst a rumour of a purge, he told Heng Samrin (the commander of the 4^th Division of the Eastern Zone) that he did not believe Pol Pot would purge him because he was Pol Pot's confidant during the war against the Lon Nol regime; Phim believed that the confusion was caused by some conspiracy against Pol Pot (Heng 2019: 67–68; also see Becker Reference Becker1998: 311). Yet, the debacle in the war with Vietnam had cast doubt in Pol Pot's mind about Phim's loyalty despite the memories and experiences the two men had shared. In the purging campaign against the leadership of the Eastern Zone, Pol Pot used the Southwest Zone, commanded by Pol Pot's former bodyguard who went by the alias Ta Mok, to conduct the purges. Eventually, Phim perished during the purge campaign (Heng Reference Heng2019: 67–68).

By the end of May, hundreds of military figures from the Eastern Zone had been called to ‘meetings,’ and all were murdered (Becker Reference Becker1998: 312). Toward the second half of 1977, the purge had reached the lower echelon of the Eastern Zone, where the young Hun Sen was a potential target of Pol Pot's purges as he was commander of a regiment. Suspecting that he was the next target of Pol Pot's purges, Hun Sen detached himself from the regional command of the DK army and created his own group of military men loyal to him to oppose Pol Pot (Hun Sen Reference Hun2011: 166).

The Border War & Mass Defection to Vietnam in 1977

Hun Sen's escape to Vietnam on 20 June 1977 was one of the many desperate escapes attempted by Cambodians who fled Pol Pot's brutal purging campaigns and starvation in the Eastern Zone between 1976–78 to seek refuge in Vietnam. Hun Sen fled to Vietnam “both out of dissatisfaction with the degradation of the country under Pol Pot and out of fear that he and his fellow officers in the Eastern Zone were next on the list for execution” (Becker Reference Becker1998: 440). However, the war between DK and Vietnam created several risks for Hun Sen's escape to Vietnam. How Hun Sen dealt with those risks is instructive of how he navigated the uncertainties.

Between 1975–78, Cambodia became a focal point in the broader conflict between China and Vietnam, which was backed by the Soviet Union (Tran Reference Tran2003: 30). Furthermore, 1977 marked a turning point in the KR-Vietnamese relations as the armed conflict between DK and SRV escalated rapidly toward an all-out war. Armed clashes along the border—the majority of them initiated by the DK armed forces—increased rapidly from 174 in 1975 to 254 in 1976 and 1,150 in 1977 (Path Reference Path2020: 60). Hanoi's strategic patience and hope for bringing the DK into a joint effort to solve the border issue ended after Hoang Van Loi's (vice-minister of foreign affairs) confidential visit to Phnom Penh in February 1977 (Path Reference Path2020: 61). After declining Loi's proposal of a summit between top Vietnamese and Cambodian leaders, Pol Pot ordered a well-planned, large-scale military attack into southern Vietnam on April 30, which shook the Vietnamese leadership out of their complacency (Path Reference Path2020: 61). As Pol Pot escalated military attacks into Vietnam in April 1977, he simultaneously intensified the purging campaign against DK cadres in the Eastern Zone to silence opposition and prevent defection (for more details, see Becker Reference Becker1998: 311–313). Moreover, as Elizabeth Becker put it best, “[t]he Center did not want the ‘tainted’ Eastern Zone people near the border when a war threatened Vietnam. The entire Eastern Zone had to be ‘cleansed’ of the ‘Khmer bodies with Vietnamese minds’” (Becker Reference Becker1998: 314).

However, Vietnam was the last place where anyone associated with the KR would want to go. Hun Sen crossed the border amid the intensified Vietnamese campaign to arrest KR spies often disguised as political refugees seeking refuge in Vietnam from Pol Pot's persecution and massacre. By mid-1977, the growing influx of Cambodian refugees into southern Vietnam validated Vietnam's humanitarian obligation to Cambodian refugees in stark contrast with Pol Pot's extremely violent policies. However, this policy posed a major security threat to Vietnam. Since the end of 1976, the Vietnamese government became increasingly alarmed by the infiltration of Pol Pot's spies among these Cambodian refugees and the rising number of sabotage activities by DK armed forces aimed at terrorizing the Vietnamese population along the Cambodian-Vietnamese border from Dak Lak to Tay Ninh province (PTT 15971: 3–5).

By April, the KR infiltration of their spies along with Cambodian refugees was brought to the attention of Hanoi's top leaders. From January to April 1977, based on reports of local police and border defence forces, the Border Committee of the Communist Party of Vietnam (CPV) transmitted a series of reports to Prime Minister Pham Van Dong, documenting in detail KR acts of destruction: from shooting Vietnamese peasants who were harvesting rice to crossing the border to plant landmines on Vietnamese territory (PTT 15971: 6–18). One report wrote the following: “Cambodia sent their agents disguised as Khmer political refugees to spy on us and even set up espionage networks deep inside our territory. Recently, we discovered nearly 100 cases of Cambodian espionage, and a number of Cambodian agents admitted to us that their leadership sent them to conduct activities [in Vietnam]” (PTT 15971: 15).

Worse, Vietnamese authorities’ perception of the threat of Pol Pot's espionage to national security was furthermore aggravated by the existence of a large population of refugees in various camps close to the border. By April 1977, there were approximately 20,000 Khmer, 10,000 Chinese and 10,000 Vietnamese residents (Viet Kieu) from Cambodia in various refugee camps at B2, which was the code name of the land in the southernmost part of Vietnam, not far from the Cambodian-Vietnamese border. A significant number of these refugees continued to cross the border back and forth to earn a living by smuggling goods, fishing and logging in Cambodian territory. The Border Committee recommended that the Vietnamese government rapidly strengthen border security and that Vietnam's border armed forces capture alive and interrogate all Cambodian people crossing the border into Vietnam (PTT 15971: 16). On 23 May 1977, the Central Military Commission, the highest military organ of the CPV, issued a directive to all Vietnamese armed forces in southern Vietnam to defend the border and launch counterattacks against the DK; within a week, from 15 to 21 of July, the Vietnamese reported 52 cases of KR aggression—increasing by 23 cases compared to the previous week—in Vietnam (Dang Uy-Bo Tu Lenh Quan Doan 4, 2004: 241). Under these circumstances, any border crossing by a Cambodian into Vietnam was a very risky one.

By mid-1977, the Vietnamese-Cambodian border conflict intensified and turned into the most complicated one because all bilateral negotiations had failed. Hun Sen and his four comrades were close enough to the border to outrun their would-be KR pursuers, but they also feared Vietnam's punishment after crossing the border. They had good reason to fear Vietnamese reprisal. According to a Vietnamese source, in June 1977, Hun Sen's regiment received an order to launch attacks into the Vietnamese border defence line at Hoang Lu. But in a biographical study of Hun Sen that was published in the 1990s, whether an actual attack occurred or how things went down was unclear and probably would remain a mystery (Mehta Reference Mehta and Julie B.1999: 64). Yet, even in the absence of reprisal, Vietnam had not yet severed its diplomatic relations with the DK. Hence, Hun Sen and his comrades could be transferred back to Pol Pot's loyalists as a peace offering by the Vietnamese government, who might want to appease Pol Pot in subsequent negotiations between the DK and SRV.

Hun Sen's Journey into Vietnam in June 1977

Hun Sen's journey to Vietnam had its root in the grievances that Hun Sen personally felt toward the military commander of Region 21 and the brutal nature of the Pol Pot regime in general (Marching Towards National Salvation 2018, Video: 1:33:54). His first child died because of the carelessness of a KR nurse who accidentally dropped the infant soon after he was born. Hun Sen was neither allowed to care for his wife nor permitted by the Region's commander to arrange a proper funeral for his dead child. Hun Sen recalled that he almost shot the commander, but he refrained from doing so because he thought about the severe consequences for his wife and family (Marching Towards National Salvation 2018).

Furthermore, Hun Sen recounted that several weeks before he decided to escape to Vietnam, he thoroughly considered his options. The first option was to mobilize some 2000 troops under his command to incite a rebellion and take control over a strategic territory in the Memot district to be used as the base for the resistance against Pol Pot's regime and a springboard for insurgent military operations against Pol Pot's armed forces. However, he concluded that such rebellion would not last for more than one month before their inevitable defeat in a bloodbath (Hun Sen's speech at the Former Location of Unit 125 in Dong Nai, Vietnam 2012). DK was in crisis, but its military remained strong. Hun Sen recalled the following: “By mid-1977, I did not have enough troops [to stand up to Pol Pot]. There were 23 divisions with a combined force of 180,000 combatants under Pol Pot's command” (Baphnom 2016: 5–6).

Leaving Cambodia was the second and, perhaps, the only viable choice. After several of his cadres had been called to attend ‘a study meeting’ and had never returned, Hun Sen decided to escape to Vietnam (Duc Reference Duc2012: 381). Yet, going to Vietnam was fraught with risks. When Vietnam still maintained diplomatic relations with the DK between 1976–77, the Vietnamese practised a policy of returning KR defectors to the DK, hoping to deescalate tensions between the two communist regimes; those defectors were executed immediately after the Vietnamese handed them over to the DK. According to a Vietnamese record, the first wave of approximately 100,000 Cambodian refugees, including KR cadres and members of the CPK, arrived in southern Vietnam by early 1977, and the Vietnamese authority “persuaded some to return [to the DK], but immediately after they crossed the border, they were executed by Pol Pot's soldiers” (Vien Lich su Quan Su Viet Nam 2010: 36).

Hun Sen was well aware of this danger. Yet, leaving for Vietnam was the most feasible option. In fact, Hun Sen also noted that there were two other options. The first was to wait for Pol Pot to decide his fate and commit suicide; Hun Sen's subordinates, including company commanders, told him that they would be happy to give their lives to Angkar, meaning the top echelon of the KR organization or Pol Pot himself, to decide as they saw fit, but Hun Sen ruled out this option (Interview with Nuch Than 2020). The last option was suicide. Hun Sen maintained that he kept this option in case his journey to Vietnam did not work out as planned. Vietnam was the natural destination because Laos was simply too far away and Thailand became the rear base for the Khmer Rouge in their war with the Vietnamese (Hun Sen Reference Hun2011: 166). Yet, crossing over to Vietnam was no less dangerous because Hun Sen and his men still risked being captured by Pol Pot's loyalists.

Lieutenant General Nuch Than was one of the four officers accompanying Hun Sen on his journey in June 1977. As General Than recalled, on the morning of 20 June 1977, the military commander of Region 21 called Hun Sen to meet him at the headquarters of the 75^th battalion and asked him for key information about the regiment, such as troops, weapons and ammunition. The commander then forced Hun Sen to write a letter to summon the officers in Hun Sen's regiment to attend a ‘study meeting’ (Hun Sen's speech at the 40^th Anniversary of the Historic Journey Toward the Overthrow of the Pol Pot Genocidal Regime 2017). In Pol Pot's purging campaign, ‘study meetings’ were usually used to mislead potential victims to avoid their resistance or escape (Path and Kanavou Reference Path and Angeliki2015). After arriving at the meeting place, the victims would be stripped of their weapons, arrested and summarily executed. Such has always been the standard operating procedure of Pol Pot's execution squad. By 1977, the purge was so widespread that it was hard to miss such a clue (Interview with Nuch Than 2020).

To display his obedience to the commander of Region 21, Hun Sen agreed to write the letter summoning his comrades to the study session at the headquarters of the 75^th Battalion on 20 June 1977. However, Hun Sen had already hatched a plan to escape to Vietnam; so he inserted a sentence that the commander of Region 21 failed to notice. Hun Sen wrote to his most senior officers: “Before going to the headquarters [of the 75th battalion], you need to come and see me first [at the regimental headquarters]” (Hun Sen's Speech During the Visit to the Historical Site 2017). The military commander of Region 21 was left to wait at the headquarters of the 75^th battalion. During the late afternoon of the same day, three officers came to meet Hun Sen: Nuch Than (special support company commander and political commissar), Nhek Hourn (deputy company commander) and San Sanh (communication company commander). A fourth officer, who was a medic of the regiment, was stationed at the regimental headquarters and was brought on board to maintain secrecy (Interview with former veterans of Unit 125 2020). The group knew that some battalion commanders had already been rounded up for execution at Wat (pagoda) Kdol. They knew that they would meet the same fate; so the group followed Hun Sen to escape to Vietnam. To avoid stirring suspicion in the barrack they walked toward the 75^th battalion, but they turned toward the border as they left the barrack. It was nine o'clock at night.

As a living witness, Nuch Than still remembered his 10-kilometre trek vividly. However, the distance was the least of their concerns. By then, the commander of Region 21 must have realized that something was amiss and had already dispatched a search party. The search party met Hun Sen's courier moments after he had left his barrack. The courier carried Hun Sen's letter to his wife in which he told her the following: “I am departing into the unknown and perhaps we would never see each other again” (Marching Towards National Salvation 2018). The courier also carried some honey and traditional Khmer wine that Hun Sen wanted to give his pregnant wife to prepare for labour. The courier managed to maintain total secrecy without raising any suspicion from the search party (Marching Towards National Salvation 2018). Hun Sen and his comrades trekked very slowly through the piercing darkness and heavy rain across the ten-kilometre stretch to the border. Moreover, they had to cross a minefield to reach the border because as the border became militarized in 1977, landmines littered the area. As Hun Sen's unit operated in the area, they knew the general layout of the minefield, but the four comrades volunteered to clear the mines, using their bare hands, for Hun Sen. The group arrived at the border crossing around midnight. They quickly prayed at the local guardian spirit shelter per the traditional Khmer animist belief (Interview with Nuch Than 2020).

The fear that they had just escaped from one enemy into the hand of another grew stronger as they reached the border crossing. However, this was not a random roll of the dice. Hun Sen's escape to Vietnam was a calculated risk. First, the group hid all their weapons before crossing the border (Mehta Reference Mehta and Julie B.1999: 70). He thought that if the Vietnamese saw those weapons, it might lead to a shootout—the worst of all possible outcomes. That was also the reason why Hun Sen brought only a few comrades; something like a 300-men party could easily be considered as a company-level attack into Vietnamese territory amid an escalating armed conflict in June 1977. Second, Hun Sen claimed he kept twelve needles with him; if the Vietnamese were to send him and his men back to the DK, he would commit suicide by using the needles to puncture his own throat (Mehta Reference Mehta and Julie B.1999: 75). Needles were not considered a weapon, and soldiers at that time normally carried needles because they would need them to sew their clothes on the battlefield. At two o'clock in the morning on 21 June 1977, Hun Sen realized that the group had walked about 200 metres into Vietnamese territory.

Without proper equipment for land navigation, the group waited for sunrise before continuing their trek. At eight o'clock in the morning on 21 June, Hun Sen and his comrades walked east to continue their journey into Vietnam. After walking for about three hours, they had travelled around six kilometres and come up on a gravel road. In one version of the narrative, it was here that the group finally disposed of the weapons and then ate the rest of their meal. They then continued their walk for about six kilometres more until two o'clock in the afternoon when the group spotted a village.

Soon, Hun Sen would know if his planning so far would pay off. The group predicted several things: they would be arrested, tied up, stripped of their belonging, or worse. Hun Sen and his men approached a group of Vietnamese workers at a rubber plantation; by chance, they met a girl born in Cambodia but of Vietnamese descent who agreed to act as their interpreter (Hun Sen's speech at the Second Historical Site in Hoa Lu village, Loc Ninh district, Binh Phuoc province, Vietnam, 2017). The Vietnamese workers were friendly to them and told them to wait there. A moment later, a group of Vietnamese village militias arrived. At the time, Hun Sen and his men were unaware that Hanoi had hatched a strategic plan to overthrow Pol Pot's regime.

Vietnam's Strategic Plan for Cambodia, 1977–78

In early 1977, Vietnam's Central Military Commission and the Vietnamese Ministry of National Defence instructed the Military Region 7 Command to establish a Vietnamese military unit, equivalent to a battalion, to recruit and train Khmer soldiers from a growing population of KR defectors and refugees (Vien Lich su Quan su Viet Nam 2010: 37).Footnote ⁴ The advantage that Hun Sen held was not that he was the only Cambodian support that Vietnam needed in a war with the DK. Alternatively, Vietnam could tap into two other groups of anti-Pol Pot revolutionaries—specifically, the Khmer revolutionaries who left Cambodia between 1974–75 and, more importantly, the former members of the ICP who chose to take refuge in Vietnam after the Geneva Conference of 1954. Belonging to the former group was Bou Thang—a former high-ranking member of the Khmer People's Revolutionary Party (a predecessor of the CPK) and who later held the powerful position as the head of the Political Commissar Directorate of the Ministry of Homeland Defense of the PRK, before briefly holding the position of minister. He and his indigenous refugees stayed and worked in Vietnam since 1975 (Bou Reference Bou2011). Among the second group was Pen Sovann, a former member of the ICP and who was later installed as the supreme leader of the PRK. Hun Sen's escape to Vietnam in mid-1977 was indeed an advantage for Vietnam, but it was far from being essential for them. It was always good to have more people, but the new anti-Pol Pot movement could still function without these KR defectors, including Hun Sen and his men of whom the Vietnamese were suspicious. However, Hun Sen was given special privileges, including military training, meetings with top military leaders of the PAVN and, eventually, an appointment as the commander of the first army unit of the Khmer revolutionary movement, Unit 125. It was extraordinary that the Vietnamese military chose the young Hun Sen to organize and command the military arm of the Cambodian liberation movement. Hanoi's strategic plan in early 1977 further reveals Hanoi's motive behind its decision to choose and groom young Hun Sen as a leader of the new Cambodian opposition to Pol Pot from September 1977 through 1978. Yet, Hun Sen proved himself to be an important asset to Vietnam.

The bulk of new evidence clearly indicates that Hun Sen's succinct knowledge of the DK political-military situation proved very useful to the Vietnamese military at a critical time when the Vietnamese Military Central Commission scrambled to search for information to craft an effective military response to the military threats posed by the DK armed forces (PTT 15860: 1). Hun Sen was not merely the Vietnamese military's useful informant when he arrived in Vietnam at the time when the Vietnamese needed crucial information about the DK's economic and military strengths and internal opposition to Pol Pol's rule. In addition to his rank of a regimental commander of Region 21, he proved to the Vietnamese as a capable leader and strategic thinker (Duc Reference Duc2012: 381). The fact that Hun Sen's escape to Vietnam was the result of Pol Pot's purging campaign against the Eastern Zone under So Phim made him a potential candidate to lead a Cambodian revolutionary front against the DK. By giving important military information to help the Vietnamese plan a major counterattack against the DK (Becker Reference Becker1998: 306), Hun Sen made himself useful to the Vietnamese military and sought to dispel the Vietnamese suspicions of him and his men as Pol Pot's spies.

Three months after his arrival in southern Vietnam, Hun Sen proved himself to the Vietnamese military as a competent young revolutionary with a huge ambition for himself and his country (Note of Comrade Van Tien Dung's meeting with Hun Sen, 27 September 1977).Footnote ⁵ Early on, Hun Sen impressed his Vietnamese military trainers, Tam Quang and Ba Cung (military code names), with his ability to learn military strategies quickly (Duc Reference Duc2012: 381). He immediately earned special attention from the Vietnamese military leadership. Likely, the importance of these briefings and documents cannot be understated. On 27 September 1977, Hun Sen received the honour of meeting with General Van Tien Dung, chief of staff of the PAVN in Ho Chi Minh City. A hero during the war against the United States, General Van Tien Dung was perhaps the highest Vietnamese military figure that any KR defector would have hoped to meet. As we shall see below, this was a pivotal meeting for the Cambodian resistance as well as for Hun Sen's career. Hun Sen's rank as regimental commander alone cannot explain such a meeting. We thus conclude that the Vietnamese must have been impressed with Hun Sen's natural talents and visions to allow him to meet such high-ranking officials.

Hun Sen grasped the opportunity to reveal to General Dung his deep disgust toward Pol Pot's betrayal of the Cambodian revolution and his own aspiration. Hun Sen explained the following to General Dung:

General Dung then assured Hun Sen by strongly supporting this role in the new Cambodian revolution: “We have a responsibility to take care of Cambodian comrades who fled to Vietnam, to create favourable conditions for you to study, improve your knowledge of Marxism-Leninism, and research on issues pertaining to your forthcoming revolutionary duties […]. It is good that Comrade is already a revolutionary” (Note of Comrade Van Tien Dung's meeting with Hun Sen 1977).

General Dung further added the following: “Comrade is still very young (only 26 years old). You still have a lot of future ahead. [You] need to maintain secrecy and change your name; otherwise, they [the KR] would terrorize your family. While you are staying here [in Vietnam], if you need anything, feel free to let us know” (Note of Comrade Van Tien Dung's meeting with Hun Sen 1977). Clearly, General Dung, an influential military leader, was impressed by the 26-year-old Hun Sen and saw potential in him as a future revolutionary leader because they were planning to create a united front against the Pol Pot regime in the ensuing months. Likewise, Hun Sen impressed General Dung with his talent, bravery and desire to save the Cambodian revolution from the Pol Pot regime. Hun Sen's nearly three-hour meeting with General Dung marked a turning point in his ascent to the top leadership of the new Cambodian front against the Pol Pot regime. The Vietnamese made their utmost efforts to support opposition forces inside Cambodia, in coordination with the Cambodian revolutionary front in southern Vietnam, to rise up against the Pol Pot regime (Vien Lich su Quan su Viet Nam 2010: 36).

In January 1978, the Vietnamese leadership made a collective decision that a military victory, followed by a regime change in Cambodia, was the most effective way to eliminate the KR threat to Vietnam (Path Reference Path, Deth, Suon and Bulut2018: 19). The fact that Pol Pot's forces escalated its brutal killing of Vietnamese villagers and the destruction of people's livelihood and properties further fuelled the emotional drive for a quick and decisive response from the Vietnamese. From December 1977 to 14 June 1978, Vietnam took 30,642 casualties, of which 6902 Vietnamese soldiers were killed (Khuat Reference Khuat2005: 160). In March 1978 alone, Vietnam suffered 12,000 casualties; 4100 Vietnamese civilians were either injured or murdered by the KR; 900 more Vietnamese soldiers were captured; and nearly 300,000 Vietnamese people were moved from the border area (Khuat Reference Khuat2005: 161). During the last six months of that year, the Communist Party of Vietnam held four conferences that involved the Politburo, the Central Military Commission and the Party Secretariat of the Party Central Committee to discuss their military and diplomatic offensives to end the Pol Pot regime (Duc Reference Duc2012: 165).

To the Vietnamese leadership, ‘the Cambodia problem’ necessitated a political and military solution. The political issue, as Prime Minister Pham Van Dong told the Vietnamese National Assembly on 23 December 1978 shortly before Vietnam's invasionFootnote ⁶ of Cambodia, involves Cambodia's national sovereignty (QH 2354: 18–19). Hanoi's rationale, according to Pham Van Dong, was that China had a strong influence in Cambodia and actively backed Pol Pot's war against Vietnam. Therefore, Vietnam had to throw its support behind an anti-Pol Pot Khmer revolution, helped it topple the DK regime and simultaneously eliminated the Chinese influence and restored the Cambodian-Vietnamese friendship (QH 2354: 18–19). As Vietnamese veteran diplomat Luu Van Loi observed: “The birth of the PRK created a basic favourable condition for restoring and strengthening the Vietnamese-Cambodian relations in general and for resolving the border problem between the two countries in particular” (Luu Reference Luu1990: 113). In other words, a pro-Vietnam regime in Cambodia would secure Vietnam's southwestern borderland and peace for its post-war reconstruction in the south.

Hun Sen's Quick Rise as a Prominent Leader in the Second Cambodian Revolution

It is important to stress that Hanoi's first choice was a ‘Khmer Hanoi’ named Pen Sovann, who was considered a loyal friend of Hanoi. Sovann—who was a veteran of the ICP, trained in Vietnam and had a Vietnamese spouse—should have been Hanoi's first choice to lead the Cambodian military front against the Pol Pot regime. Among Khmer Hanoi, Bou Thang and Seuy Keo fled from northeastern Cambodia to seek Vietnamese support in 1975; Say Pouthang from Koh Kong fled to Thailand as early as 1974. These men were among the top contenders of power in the Khmer revolutionary front in the late 1970s. Thus, it is puzzling how the 26-year-old Hun Sen won the Vietnamese trust and favour so quickly. When the first Cambodian military unit, with a code name Unit 125, was formed on 12 May 1978, Hun Sen became its commander. However, it is important to consider how the Hun Sen faction rose to become Vietnam's top choice to organize and command the first embryonic army of the front.

When Hun Sen arrived in Vietnam, he received good treatment, but the atmosphere was one of suspicion and uncertainty. He and his men were treated to rice in a big pot for five people and some pork soup. To them, it was some sort of a feast because they had not eaten rice for several months due to the famine under the DK. However, the Vietnamese distrust towards them remained high—wondering whether they were Pol Pot's spies. That was the question that dominated the Vietnamese interrogation sessions after the first contact. The suspicion was heightened by the fact that Hun Sen was 25 years old at the time but controlled a regiment. With limited understanding of Vietnamese, Var Po Ean, the medic and one of the four comrades that accompanied Hun Sen overheard the militiamen asking each other: “How could such a young man have controlled a unit equivalent to what a Vietnamese colonel would have? He must be lying” (Interview with the former veterans of Unit 125 2020). Unable to determine the truth, the militiamen transferred Hun Sen and his comrades to the Loc Ninh District authority at 6:00 pm on 21 June and then to Song Be provincial capital on 22 June. There was one recurrent comment from the Vietnamese interrogators: “You must be lying. You are too young to know all these details.” Prime Minister Hun Sen recalled that he repeatedly heard the Vietnamese words ‘noi lao’, meaning ‘lying’ (Hun Sen's speech at the Third Historical Site in Village 9, Loc Ninh District, Binh Phuoc province, Vietnam 2017).

The Vietnamese questioning of Hun Sen and his comrades was part of the Vietnamese military's routine standard operating procedure to arrest Pol Pot's spies and extractFootnote ⁷ military intelligence. Cambodians who fled to Vietnam were routinely detained, their identities determined, and they were interrogated to capture Pol Pot's spies disguised as KR defectors. In July 1977, the Vietnamese police reported that the KR continued to dispatch their spies into southern Vietnam and connect with their networks deep inside Vietnam. The Vietnamese put a high premium on the capture of KR military officers. For instance, from a series of arrests in early July, the Vietnamese police paid special attention to the case of Nheng Xa-Ran, a KR platoon commander in Svay Rieng province, who was arrested on 9 July. Xa-Ran was dispatched by his superiors to make a connection with his networks inside southern Vietnam to spy on Vietnam's border defense (PTT 15971: 33). KR military officers like Xa-Ran had been arrested and interrogated by the Vietnamese military well before Hun Sen and his men arrived in southern Vietnam. Out of fear that Hun Sen and his men could possibly be KR spies, Hun Sen and his men were detained and interrogated. To the Vietnamese, Hun Sen and his men could just be another group of spies who disguised themselves as refugees or defectors. Therefore, the Vietnamese needed to determine who they really were.

During his questioning, Hun Sen told the Vietnamese military that he was a mid-ranking KR commander and that he and his four comrades were part of a group who had revolted against Pol Pot's regime (Becker Reference Becker1998: 440–441). He was the commander, and yet he was not the oldest of the group; this aroused suspicion in the mind of the Vietnamese commander. To make the matter worse, at some point during the interrogation, the Vietnamese commander was furious that Hun Sen was lying because the number of soldiers that he claimed to have control over did not match with his rank. Sensing that some words might have been lost in translation, Hun Sen spoke French to the Vietnamese commander and cleared the misunderstanding that he was a regimental commander [Vietnamese: Trung Doan] and not a squad leader [Vietnamese: Trung Doi], like the interpreter had said (Mehta Reference Mehta and Julie B.1999: 74). The Vietnamese commander then corrected his interpreter.

After having established Hun Sen's real identity, the Vietnamese authority paid unusual attention to this regimental commander in a few manners. First, the questioning, which was supposed to conclude in roughly an hour or less, was instead extended late into the night to the point where the people who came with Hun Sen began to fear that the Vietnamese had already executed their commander (Mehta Reference Mehta and Julie B.1999: 73). After that, he was allowed to meet and discuss with colonels and generals in the PAVN to “brief them about the disaster currently unfolding in the DK and that only Vietnam could help” (Hun Sen's speech at the Commemoration Ceremony of Unit 125 2012). Therefore, it is interesting to consider what Hun Sen told the Vietnamese and what made the Vietnamese military pay special attention to this young regimental commander. Notably, his arrival consequentially coincided with the urgency with which the PAVN leadership had intensified their intelligence gathering on Pol Pot's military activities. Hun Sen's briefings contained crucial military intelligence that the Vietnamese military intelligence and other KR defectors could not reveal. That drew special attention from the Vietnamese military leadership.

On 8 July 1977, Hun Sen was able to write two reports to the Vietnamese leadership, and on 9 July he wrote another letter. In his speech to commemorate the 35^th anniversary of the establishment of Unit 125, Hun Sen also recalled the importance of those briefings and letters, saying “I think the Vietnamese leadership still keeps those reports” (Hun Sen's speech at the Commemoration Ceremony of Unit 125 2012). After a series of questioning by Vietnamese Lieutenant Colonels and Generals of the Military Region 7, Hun Sen submitted two hand-written reports to the Vietnamese offering crucial information about the internal socio-economic, political and military situation of the DK from the local to central levels (Hun Sen's speech at the Commemoration Ceremony of Unit 125 2012). The information contains information about KR military dispositions along the border; this information would be vital information for the Vietnamese who were preparing for a major campaign into Cambodia. As a regimental commander on Pol Pot's eastern front, Hun Sen could know the disposition of troops in his area of operations and perhaps the adjacent areas, but it was unlikely that he would appreciate the military situation on the whole front. Because we do not have access to Hun Sen's hand-written reports in the Vietnamese custody, we suspect that the essential content in those reports and briefings must be Hun Sen's strategic assessment of the situation and his visions for resolving the problem. The political and military value of the information provided by Hun Sen and his rank would also distinguish him from a mere informant and may have presented him as a potential leader and a key player that the Vietnamese would need in the political solution to the Cambodian problem.

In early 1978, Hun Sen made extraordinary progress with his career, earning more trust from the Vietnamese military leadership. At this time, two hundred potential Cambodian cadres, among them the surviving veterans of the 1954 group, defectors from the DK army and members of the educated classes of the former regimes who could be persuaded to join the Kampuchea United Front for National Salvation (KUFNS), received training at the former police training school in Thu Duc, Ho Chi Minh City (Slocomb Reference Slocomb2003: 45). Among his peers, the young Hun Sen stood out for his intellect, quick learning and willingness to work hard. Two Vietnamese military officers by the names of Tam Quang and Ba Cung (Phung Dinh Am), who were assigned to train Hun Sen in his early days in Vietnam, were impressed by his intelligence and strategic thinking—after only several training sessions (Duc Reference Duc2012: 381). To his trainers’ surprise, Hun Sen was able to articulate his strategic thinking about military and political affairs in Vietnamese writing, and he quickly earned the respect of other Vietnamese military officers (Duc Reference Duc2012: 381). While Hun Sen was being groomed by the Vietnamese to become a Cambodian leader worthy of Hanoi's trust, Pol Pot's provocative attacks into Vietnam in early 1978 helped propel Hun Sen to the centre of Vietnam's rapidly mobilized anti-Pol Pot movement.

In early April 1978, he was again given another rare opportunity to and honour of meeting with a high-ranking Vietnamese military officer, General Tran Van Tra, Commander of the PAVN's Military Region 7. Evidently, it was Hun Sen, who first made an official request to Hanoi's leaders and the Vietnamese Ministry of National Defense via General Tra that Vietnam help build an anti-Pol Pot revolutionary army, although the Bou Thang group had defected to Vietnam earlier than Hun Sen did and had more men (Ngo 2008: 151). General Tra informed the young Hun Sen that Vietnam decided to support a Cambodian liberation movement. Hun Sen expressed gratitude to the general but requested that Vietnam support the movement only in terms of military training and logistics and that the Cambodian side manage their own political affairs (Hun Sen's Speech Commemoration Ceremony of Unit 125 2012). To Hun Sen's surprise, the Vietnamese accepted his request. From the perspective of the veterans of Unit 125, this military unit was established not as an entirely Vietnamese initiative but as a cooperative work between the Vietnamese and Cambodians. This was perhaps the reason why the unit gained its legitimacy and was later expanded into the Kampuchea Revolutionary People's Army (KPRA) and, its modern successor, the Royal Cambodian Armed Forces.

Veterans of Unit 125 separately confirmed the Cambodian control of the political indoctrination of the unit. In an interview for the 2018 documentary film, Marching Towards National Salvation, General Sao Sokha, who is the current commander of the Gendarmerie, recalled that, when he joined Unit 125, he was appointed as the assistant to Hun Sen and that his hobby was to keep a transcript of Hun Sen's ‘political lectures’ (Cabinet of Samdech Techo Prime Minister Hun Sen 2018). General Sokha's recollection 40 years later, and particularly in this documentary film about Prime Minister Hun Sen's legacy, was probably aimed at praising the young Hun Sen's talents, but it may have inadvertently confirmed Prime Minister Hun Sen's account that the Cambodians oversaw the political indoctrination of Unit 125.

More important corroborating evidence of Hun Sen's request for managing the Cambodian affairs under his command appeared in an unpublished memoir of Hun Sen's early Vietnamese mentor, Ambassador Ngo Dien. The Vietnamese ambassador wrote as follows: “Unlike Pen Sovann [leader of the Khmer Hanoi faction], who desired to show the Vietnamese that he could do everything on his own, and did not need help from Vietnamese advisors, Hun Sen early on never wasted an opportunity to exploit Vietnamese advisors/specialists’ assistance. However, in selecting his cadres and solving any issues pertaining to the internal affairs of the Cambodian side, he often did that on his own [meaning ‘free from Vietnam's help’]” (Duc Reference Duc2012: 381).Footnote ⁸

The Vietnamese likely agreed to Hun Sen's request for the Cambodian side to oversee the ideological and political training of Cambodian revolutionaries because of Hanoi's awareness of the Cambodian comrades’ oversensitivity to the Vietnamese superiority and Cambodia's own self-interests in the entire campaign to overthrow and replace the DK regime. Cambodian communists possessed strong resentment at “Vietnam's ‘big brother’ complex born of many years of leading the military and political struggle for Communist power in Indochina” against the French colonialists in the first half of the 1950s and against the American imperialists in the first half of the 1970s (Quinn-Judge 2006: 214). In the late 1970s, the Vietnamese were well aware of Cambodian comrades’ concerns about Vietnam's unchecked influence and desire to dispel such fear in the minds of Vietnam's new Cambodian allies, of whom many were KR defectors. Just before the Vietnamese army was ready to march into Cambodia, Prime Minister Pham Van Dong told his colleagues at the National Assembly in Hanoi on December 23 that there were two intertwined solutions to the Cambodian problem: (1) defeat the KR militarily to defend Vietnam's national sovereignty; (2) a regime change, which required that Vietnam fully back the Cambodian revolution to overthrow the DK regime. In his own words, he stated:

On 12 May 1978, at the Unit 977Footnote ⁹ (Military Region 7) headquarters in Thu Duc (Ho Chi Minh City), Hun Sen, with the support of the Vietnamese military leadership, established the first armed forces of the Cambodian revolution, bearing the name “The Revolutionary Armed Forces of the United Front for the National Salvation of Kampuchea” with the 26-year-old Hun Sen as its commander (Vien Lich su Quan su Viet Nam 2010: 41–42). According to Hun Sen, Unit 125 was named after the day and month (12 May), not the number of 125 officers this unit consisted of when it was founded (Hun Sen's interview by a filming crew for the 40^th Commemoration Day of the Historical Journey Leading to the Overthrow of Pol Pot's Genocidal Regime, on 13 June 2017, Phnom Penh, Cambodia; Ngo Reference Ngo2008: 152). Unit 125 was based at Suoi Ram village, Long Giao commune, Cam My district, Dong Nai province (Vietnam).

To Hun Sen, the Cambodian revolution had gone terribly wrong—to the horror of DK— and was remade through the December 1978 creation of KUFNS, which participated in the overthrow of the DK (Noren-Nilsson Reference Noren-Nilsson2016: 125). Unit 125, colloquially known among former veterans as the ‘Long Giao units’ had grown into 21 battalions and several other specialized units when they entered Cambodia in 1979. Later, each of the provinces in Cambodia received one battalion, which became the backbone of the Provincial Military Commands of the KPRA, except for the Kampong Cham province, which inherited two battalions, and Phnom Penh, with four battalions, due to their respective large size and strategic importance (Hun Sen's speech at the Commemoration Ceremony of Unit 125 2012). The other three provinces, namely Koh Kong, Rattanakiri and Mondulkiri did not receive any of these battalions because they already had their own forces. Say Phouthang commanded forces in Koh Kong whereas Bou Thang commanded forces in the other three provinces.

Some of them were augmented and combined with other units to create the mobile division, including the 4^th Division, the 6^th Division, the 179^th Division, the 196^th Division and the 286^th Division (Nhem Reference Nhem2018: 123–6). Except for the 196^th Division, which was decimated by the KR forces in 1989, the other four divisions played a major role along with other KPRA units in withstanding the brutal, combined offensive of the Coalition Government of Democratic Kampuchea after the Vietnamese withdrawal in 1989. It was these units that fought to strengthen the hands of Hun Sen and the PRK during the negotiation process, leading to the Paris Peace Agreement on 23 October 1991 (Nhem Reference Nhem2018: 123–6). Overall, Vietnam's political discourse of adhering to its proletarian internationalism and showing absolute respect for Cambodia's national sovereignty provided an opening for the idiosyncratic realist Hun Sen to demand some political independence from Hanoi to lead Hun Sen's Cambodian rank-and-file soldiers and to effectively improve his competent leadership and legitimacy among his Cambodian colleagues.

Epilogue

Veterans of Unit 125 often spoke fondly about their experience with and memories of a Vietnamese expert tasked with training the Cambodian soldiers of Unit 125, which eventually became the Cambodian liberating force. He was Brigadier General Phung Dinh Am, but he was normally known among the former veterans of Unit 125 as ‘Ba Cung.’ In mid-1978, General Tran Van Tra, Commander and Party Secretary of Military Region 7, appointed Ba Cung as the head of Ban K (Kampuchea Committee) to assist Hun Sen in organizing Unit 125 (Ngo 2008: 151). After the war, he wrote a memoir, which was translated into Khmer in 2009. The title is Ba Cung, Brigadier General Phung Dinh Am, Connecting with Three Generations of the Land of Angkor (Phung 2019). As the title and the tone of the book suggest, Ba Cung was intimately involved in the revolutionary relationship between the two countries across three generations. We know that the first one was not very successful. During the struggle against colonial power, many Cambodian revolutionaries resented the Vietnamese withdrawal of support after the Geneva Conference in 1954. In the second generation, the DK eventually fought against Vietnam in a full-scale war. The memory of the Vietnamese imposition of control in the past led to radical anti-Vietnamese nationalism under Pol Pot and eventually a bloody war with Vietnam, which compelled the latter to topple Pol Pot's regime.

The year 1979 was the third generation of Hanoi's attempt to build a pro-Vietnam revolutionary regime. This time, the Vietnamese would try to make it right. To win in the court of world public opinion, Vietnam needed to show that its presence in Cambodia was not an occupation but one of proletariat internationalism. One major policy was the attempt to avoid the ‘big brother’ mentality. In 1979, Le Duc Tho, whom the Politburo put in charge of nation-building in Cambodia, reminded Vietnamese experts in Cambodia to “refrain from big-country chauvinism”Footnote ¹⁰ (Path Reference Path2020: 118). However, once the tanks started rolling, these plans fizzled away. From the top leadership down to the lower level, the animosity between Vietnam and Cambodia emerged almost immediately. There were indeed good and rational people on both sides, but as a group, a different dynamic was at play. There were Cambodians who saw the Vietnamese as occupiers, despite the liberation from genocide and assistance in nation-building. Likewise, on the Vietnamese side, some started to adopt the ‘big brother’ mentality by treating the Cambodians as inferior, despite the attempt by some top Vietnamese officials to adhere to the declared mission of proletariat internationalism.Footnote ¹¹

In his book, Ba Cung noted an incident during a political indoctrination session, which he lectured about well after 1979, where some of his Cambodian students vehemently defended Pol Pot's policy as correct and noted that the mistakes occurred only in the implementation stage (Phung 2019: 109–111). To some Cambodian cadres in the PRK, who were former KR cadres, Pol Pot's intention was good and so was his policy, but the local people either applied the wrong principles or simply sabotaged it. Ba Cung had to intervene and tried to instil some sense into the dissenters. Some changed their mind, but others still did not agree with Ba Cung; one of them later escaped to the Cambodian-Thai border and organized a resistance movement against the Vietnamese (Phung 2019: 109–111).

Although there were Cambodian people who did not trust the Vietnamese, on the Vietnamese side, we also see cases where some low-ranking Vietnamese soldiers and regional commanders in the Cambodian battlefield actually adopted the ‘big brother’ mentality that Hanoi had tried very hard to avoid. As historian Sophie Quinn-Judge correctly observed, Vietnam's ‘big brother’ complex—borne of many years of learning the military and political structure for the Communist power in Indochina since 1970—remained strong after toppling the DK regime in 1979: “The policy of sending Khmer functionaries for extended periods of ‘study’ in Ho Chi Minh City or Hanoi was another element of the VCP's effort to create a more pro-Vietnamese Cambodian elite. These courses of political study, by all anecdotal evidence from foreign aid workers, do not appear to have made much impact, however, and served to increase Cambodian fears about long-term intentions of their Vietnamese mentors” (Quinn-Judge 2016: 214).

For example, in the area of operation under Front 479 covering Siem Reap–Ouddar Meanchey-Battambang provinces, there is evidence of misconduct by Vietnamese soldiers, and some cases were driven by contempt of the local Cambodian people (Path 2020: 118–125). The distrust reached the top echelon of Front 479, the Vietnamese volunteer army command in charge of Siem Reap and Battambang province, and it erupted between 1982–1983 when Vietnamese military officers from Front 479 conducted a brutal purging campaign of Cambodian officials and soldiers in Siem Reap. When Hanoi finally realized its mistake, it tried to stabilize and restore the situation by sending General Chu Huy Man, a member of the Politburo of the Communist Party of Vietnam and the Chief of the Political Directorate of the Ministry of Homeland Defence, to offer a personal apology to the Kampuchea People's Revolutionary Party and the victims (Path 2020: 118–125). Yet, it was too late. Many Cambodian people in that province left the PRK to join the KR and other resistance movements after the Siem Reap purges in 1983. A former KR commander in Anlong Veng district along the Cambodian-Thai border recalled with pride in his tone that the 1982–1983 purge was a boon for the KR resistance: “There were so many people [who escaped from the Vietnamese purge in Siem Reap] so much so that we actually lacked the rice to feed those people” (Interview with a former KR battalion commander 2012). There were genuine attempts by people on both sides to try and break out of this vicious cycle, but both Cambodia and Vietnam appeared unable to find an optimal solution.

However, one important lesson from this historical episode is that the Vietnamese agreement to Hun Sen's request for the Cambodian side to manage their political affairs and indoctrinate their own combatants was crucial for the success of the military wing of the Cambodian revolutionary front, i.e. Unit 125, between 1977–79. Unit 125 was a Cambodian unit whose personnel were drawn from the Cambodian refugees, including former KR defectors. The Vietnamese provided support with military and technical training, weapons, ammunition and logistics, but they accepted Hun Sen's request that the Cambodian revolutionaries manage their own political affairs. Such a decision actually bred strength and legitimacy into Unit 125, which eventually became the backbone of the KPRA and its modern successor, the Royal Cambodian Armed Forces (RCAF).

This is a critical juncture that is often missed in the literature, which tends to attribute the success of the PRK entirely to the Vietnamese support. There is no doubt that the Vietnamese played a crucial role in building and strengthening the PRK, but it was the offspring of Unit 125 that enabled the PRK to stand up on its own after the Vietnamese withdrawal in 1988. Most of the Unit 125 veterans became Hun Sen's loyal generals in the RCAF. After their liberation in January 1979, many veterans of Unit 125 went on to serve in various positions in the military as well as in the civilian sectors. In the military sector, in particular, many veterans of Unit 125 served in the Ministry of Homeland Defence, military regions and the regular units. The battalions of Unit 125 formed the backbone of all the Provincial Military Commands as well as the 4^th, 6^th, 179^th, 196^th, and 286^th Divisions (Nhem Reference Nhem2018, Chapter 4 and 5). After the withdrawal of the Vietnamese troops in 1989, these units and the Provincial Military Commands fought the troops of the Coalition Government of Democratic Kampuchea to a stalemate and brought them to the negotiation table (Nhem Reference Nhem2018, Chapter 6). In short, before 1979, the main utility of Unit 125 was political: it helped make the PRK legitimate because it was a Cambodian unit. Between 1989 and 1991, however, Unit 125 and its offspring also had military utility: they enabled the PRK to negotiate from a position of strength. Many veterans of Unit 125 who now occupy the upper echelon of the RCAF not only laid the foundation for Cambodia's modern armed forces but also are Prime Minister Hun Sen's most loyal generals.