The Decision to Invade Cambodia December 1978

 The Decision to Invade Cambodia

DECEMBER  1978 

This chapter focuses on the gradual change in Hanoi’s strategic thinking and the corresponding policy shift from the peacetime focus on the twin goals of economic recovery and modernization and defense of national sovereignty—as spelled out in the first FYP after unification, which the Fourth Party Congress approved in December 1976—to its decision to invade Cambodia in December 1978. I argue that the wider strategic calculation—that is, the alliance between DK and the People’s Republic of China (PRC), backed by the United States, which posed a serious threat to the SRV—played a more significant role in Hanoi’s decision making vis-à-vis Cambodia than either local factors (border raids by DK forces or the territorial dispute between DK and the SRV) or geopolitical concerns steeped in long-term historical conflicts. Hanoi’s decision to invade Cambodia in 1978 was a bold but calculated move intended to cement the Vietnamese-Soviet alliance and position Vietnam as the frontline state opposing Chinese expansionism in Indochina. Hanoi expected to use Vietnam’s geopolitical position to draw massive economic and military aid from the Soviet bloc to address Vietnam’s domestic economic crisis, bolster its national defense, and build pro-Vietnam socialist regimes in Cambodia and Laos.

Relying on new evidence from Vietnamese archives, this chapter revisits an old but still unresolved question: why did Vietnam invade Cambodia in late December 1978? The causes of the Third Indochina War have been the subject of a number of excellent studies. However, fewer studies have focused specifically on the question of why Vietnam decided to invade Cambodia in December 1978 even though Hanoi’s decisions and actions were arguably the most consequential triggers of the war as they led to China’s invasion of Vietnam in February 1979 and the subsequent confrontation that turned into the Third Indochina War.² We know now that Moscow had little influence over Hanoi’s decision to invade Cambodia.³ Three contending accounts have emerged to explain the Vietnamese invasion. The first explanation attributes the invasion to Vietnamese leaders’ irrationality and ideology. The main proponent of this theory is Stephen J. Morris (1999) in his book Why Vietnam Invaded Cambodia. His main explanation emphasizes “the imperial ambition of Vietnam’s communist leadership to dominate the formerly French Indochina (background cause) and the ideological and paranoia-induced misperception” of all three players (immediate or trigger cause).⁴ Morris concluded, “Vietnam invaded Cambodia because it saw the action as a means of simultaneously achieving the two purposes of ending the military attacks begun by the Democratic Kampuchea (DK) and satisfying a long-standing ambition to dominate its weaker neighbor.”

However, the theory that Vietnam had a long-standing ambition to dominate Indochina explains its invasion of Cambodia is based on an implicitly faulty assumption that Hanoi's immediate concerns in the late 1970s had little effect on the course of its decision-making. As Gareth Porter succinctly argued, "Vietnam's invasion and occupation of Cambodia were not part of a plan which Hanoi had waited for nearly five decades to put into action, nor were they the inevitable outcome of the Vietnamese conception of Indochina." In fact, as the Cold War historian Odd Arne Westad points out—and I agree—the invasion was not based on ancient resentments or predicaments but resulted from political decisions made by leaders who were bound by what they saw as the changing realities of their own time.⁹ Historical and cultural lenses colored the Khmer Rouge's perception of Vietnamese intentions, but this cannot explain Vietnam's own perceptions and intentions in the late 1970s that led to its decision to invade Cambodia in 1978 and to occupy it for the next decade. The Khmer Rouge (KR) anti-Vietnamese ideology and its provocative attacks were certainly contributing causes, but they are not sufficient to explain Vietnam's decision to invade. A fuller account needs to factor in Hanoi's tangible domestic and foreign policy objectives at that time, as this chapter will undertake.   

In China and Vietnam: The Politics of Asymmetry, Brantly Womack (2006), to some extent, supports Morris's "irrationality" argument; for him the key cause of the Vietnamese invasion of Cambodia is located in the "systematic misperception" in Sino-Vietnamese asymmetric relations in a novel situation after 1975.10 He writes, "Vietnam thought that it could present the region and the world with the fait accompli of its control of Indochina, and China and Southeast Asia would quickly adjust, as they had to Vietnam's victory in 1975." 

The second explanation contends that Marxist-Leninist ideology was the main cause of the Third Indochina War. Notably, political scientist Tuong Vu attributed the key cause of the Sino-Vietnamese conflict to Vietnam's Marxist-Leninist ideological belief in vanguard internationalism, which he defines as "a mixture of fervent national pride and fiery revolutionary ambitions."12 Through such ideological lenses, Vietnam saw China's collusion with the imperialist United States as a threat to its identity and international socialism. Vu rejected Vietnamese nationalism and geopolitical factors such as the Sino-Soviet rivalry as the main cause.13 He writes, "Hanoi's quick fall back into Moscow's open arms [in 1978] indicated the more powerful pull of ideology compared to the push of the international structure."14 The problem with Vu's ideology-centered argument is that it cast the Vietnamese leadership as one monolithic group of pure ideologues rather than strategic thinkers who were factional at times.15 This by no means rules out the role of ideology in this conflict, but a more convincing argument has to take into account a nuanced appreciation of Hanoi's tangible objectives in the context of the domestic and foreign policy crisis in 1977-78.

Unlike the studies mentioned above, which privilege leaders’ irrationality, including their paranoia, misperceptions, and ideology, I argue that Hanoi’s invasion decision in December 1978 was rational given the domestic and international imperatives at that time. By rationality, I mean “subjective rationality.” As T. V. Paul stated, this concept posits, “The values, beliefs, and expectations of a decision-maker are important factors that determine his probabilistic assessment before he undertakes a course of action.”¹⁶ In such a conception, “A course of action is rational only relative to a possessed body of information—that is, beliefs, and desires, and priorities—in terms of which the merits of the available courses of action can be rationally evaluated.”¹⁷ The third explanation emphasizes key causes in 1977–78. Just two years after the war, Gareth Porter provided a penetrating analysis, with foresight, of Hanoi’s decision making despite his lack of access to high-quality information at the time. Porter argued, “While the Vietnamese leadership approached their relations with Beijing and Phnom Penh with certain ideological, geopolitical and historical-emotional predispositions, it was a particular configuration of the external developments in 1978 that triggered the dramatic Vietnamese invasion of that year.”¹⁸ Specifically, he argued that the interplay between the two sides of Vietnam’s foreign policy crisis—that is, an irreversible two-front conflict with China and its ally, the DK regime—led to its decision to invade Cambodia.¹⁹ Similarly, the journalist Nayan Chanda argued that Vietnam reluctantly decided to invade Cambodia only after all prospects for effecting either a change in Pol Pot’s hostile policy  toward Vietnam or a coup against the DK leadership had failed.²⁰ Chanda’s pathbreaking work provides an insightful and detailed account of the origins of the Third Indochina War, but his work does not provide adequate insight into the “black box” of Hanoi’s decision making during the crucial years 1977–78. The focus on the overt threat posed by the Sino-DK alliance in 1977–78, however, overlooked a key connection between the economic and foreign policy crises that converged during a rather brief period from late 1977 to mid-1978, which compelled Vietnam to recalibrate its prioritization of its national security and make a radical shift in foreign policy.

As this chapter shows, Hanoi’s decision to invade Cambodia was made as early as January 1978, and war preparations were under way well before Vietnam signed its alliance with the Soviet Union in November of that year. Building on these early works, I develop a rational explanation for Hanoi’s decision to invade Cambodia by examining the link between the economic and foreign policy crises of 1977–78. Relying primarily on interviews, Hoang Minh Vu presents the qualified argument that after failed negotiations from April 1977 to February 1978 the invasion was ultimately a case of “preemptive self-defense” whereby the Vietnamese government responded with overwhelming force to what it misperceived to be a threat to its survival from a two-front war against an alliance between China and DK.²¹ I agree with Vu’s and Porter’s conclusion that the immediate causes were located in 1977–78, not Vietnam’s long-standing hegemonic tendencies. However, Vu’s assertion that Hanoi’s misperception of this two-front threat was the cause of its decision to invade is a post hoc or postinvasion argument. To my point, Vu asserts, “The story of the Vietnamese decision to invade Cambodia in 1977–78 should be best told as a tragedy in which Vietnam responded inappropriately to a conflict instigated by Khmer Rouge radicalism due to a series of misperceptions.”²² Was it misperception, ideology, or strategic interests?

I contend that Hanoi's decision to invade was a rational one based on its strategic interests in that by late 1977 and early 1978 all negotiations over border disputes with China and Cambodia had failed, military confrontations had escalated on both the southwestern and northern frontiers, and Vietnam was engulfed in economic and sociopolitical crises that threatened the survival of the party-state. Vietnam's invasion of Cambodia was driven by its leadership's rational political decision to cement its alliance with the Soviet Union with the objective of obtaining economic and military aid to address the national security threat and the economic crisis at home. This is a case in which post-1975 Vietnam plunged into domestic and foreign policy crises and then came to view the invasion of Cambodia and the alliance with the Soviet Union—a communist superpower with which it had forged an ideological affinity since 1970 as the most optimal solution. Unlike existing works that privilege the strutural deter. minant, that is, the Sino-Sovie rivalry, or Vietnam's foreign policy, I argue that the actual choice Vietnam made under such structural pressure had more to do with the strategic thinking and worldviews of Vietnamese leaders and Vietnam's domestic political constraints. 

The Threat of the Sino-Khmer Rouge Alliance, 1975-77

Harboring irredentist nationalism and racial hatred toward the Vietnamese, the DK identified Vietnam as its number-one enemy as early as 1973. Referring to the essence of DK nationalism, historian Ben Kiernan writes, “The DK defines as ‘traitors’ or ‘Khmer bodies with Vietnamese minds’ broad categories of the Cambodian population who do not accept the DK leadership in an anti-Vietnamese crusade.”24 From the DK perspective, the Vietnamese-Khmer Rouge alliance in 1970-73 was a necessity not a choice. From the very beginning, the Khmer Rouge chose to accept the more distant, more radical Chinese Communists as patrons because they had ideological differences with the Vietnamese, as well as complicated historical legacies.25 In his announcement, on March 23, 1970, of the establishment of the National United Front of Kampuchea (FUNK), the deposed Cambodian head of state Norodom Sihanouk made no mention of the Vietnamese army’s role in the war against the Lon Nol regime. However, from the Vietnamese perspective, the Cambodian revolution owed its existence and victory to the support of the Vietnamese Communists.26 In the Vietnamese Communists’ account, when the FUNK army was created on May 4, 1970, they dispatched military advisers to help build and train Cambodian troops, and by the end of 1970 they had helped the Cambodian Communists create twenty-seven platoons, fifty-three companies, and nine battalions with a total of ten thousand soldiers. By the end of 1972, before moving their headquarters out of Cambodia, the Vietnamese Communists had assisted the Khmer Rouge in liberating thirteen of Cambodia’s seventeen provinces.28 Hence the Vietnamese believed that they had helped the Cambodia Communists grow from small units to a strong army that established a firm foothold in a large territory under its control and from there brought the armed struggle to a victorious conclusion in April 1975.

The stark contrast between the two communist parties' viewpoints of the consequences of the 1973 PPA was manifested in an unpleasant encounter between the two sides the following year. In September 1974, when the top Leaders of Vietnam’s Provisional Revolutionary Government (PRG) made a long, exhausting journey through the jungles of Cambodia to visit Cambodian Communist leaders in the liberated zone; they received a cold reception.30 The PRG delegation’s mission was to make clear that the 1973 PPA, to which Cambodia was not a party, created favorable conditions for the Cambodian revolution rather than undercutting the struggle. 

Rather than dispelling Cambodian resentment, this reasoning by Vietnam was perceived by the Khmer Rouge leadership as adding insult to injury. In actuality, the PPA had two adverse consequences for the Cambodian revolution. First, the PPA led to the quick withdrawal of most Vietnamese Communist troops from the interior of Cambodia, and soon after, by accident or design, arms shipments from the Vietnamese designated for the Khmer Rouge were delayed or failed to arrive in Cambodia via the Ho Chi Minh Trail. Thus the Khmer Rouge fought alone on the Cambodian front. Second, Cambodia became the sole target of American bombing. To the Khmer Rouge, as Elizabeth Becker noted, "The accords were one more betrayal by their communist allies."32

The Khmer Rouge response after the PPA was signed was "an undeclared war of revenge," to use Becker's words, against the Vietnamese Communists. Sales of Khmer produce and rice to the Vietnamese Communists were banned, and the Viet Cong was no longer allowed to travel through Cambodia freely.  

As soon as the Pol Pot regime came to power in April 1975, it wasted no time in eliminating any influence that its Vietnamese Communist ally had left in Cambodia. On April 21, 1975, five days after the liberation of Phnom Penh, the regime demanded that the Vietnamese terminate all broadcasts from Hanoi in support of the Cambodian revolution and began its own radio broadcasts from Phnom Penh. From August 1, 1970, to April 22, 1975, Hanoi had guaranteed uninterrupted radio broadcasts, even when the capital was under heavy US bombardment,34 to support the Cambodian Communists’ propaganda war against the Lon Nol regime. Two weeks after Phnom Penh was liberated and on the same day that the Vietnamese Communist forces entered Saigon, DK used military force to take over Vietnam’s islands, which they believed once belonged to the Khmer nation. On April 30, Khmer Rouge military units attacked Koh Tral (Phu Quoc in Vietnamese) to revive an old claim to the island. On May 3, they took over Koh Krachak Ses (To Chu in Vietnamese) and “evacuated” some five hundred Vietnamese inhabitants of the island, who were never heard from again. Two weeks later the Vietnamese launched a counterattack, killing many Khmer soldiers and taking about three hundred prisoners.35 During a visit to Vietnam on June 11–14, 1975, Pol Pot expressed his gratitude to the Vietnamese for their assistance during the war against the Lon Nol regime in a deceitful attempt, however temporary, to dispel Hanoi's concerns about the DK's border incursions. The Vietnamese leadership did not suspect that Khmer Rouge resentment over the 1973 PPA and cold relations thereafter would lead to attacks on Vietnam after 1975.

For its part, Hanoi privately acknowledged Vietnam's violation of Cambodia's territory in some cases. In a late 1977 report furnished to the Politburo, the Border Commission (Uy Ban Bien Gioi) of the Party Central Committee raised the issue of “local Vietnamese armed forces and authorities along the border unknowingly violating Cambodia’s territory” due to their poor knowledge of the border between the two countries.36 The report further noted, “In some cases, local Vietnamese authorities did not know that Vietnamese land was being occupied by the Cambodians, and in some other cases, they mistakenly control Cambodia’s territory.”37 This report shows that the status of the border was unclear when negotiations failed. Nonetheless, the Border Commission concluded, “It is overwhelmingly clear that Cambodia’s intention is to take over Vietnam’s territory as much as it possibly can and invent more cases of territorial dispute so that it can increase its leverage in subsequent negotiations with us.”38 This report evinces Hanoi’s perception that its preference for the resolution of boundary disputes rather than bilateral negotiations was giving way to long-term concerns about the DK leadership using the pretext of wanting to negotiate to buy time to increase DK’s territory. To understand how Hanoi reached such a conclusion, one only has to review the attempts of the DK regime to deceive Hanoi after 1975. From mid-1975 to late 1976, it was the Sino-Soviet conflict, not Khmer Rouge incursions into Vietnam, that seriously concerned the Vietnamese leadership due to its impact on the country’s domestic and foreign policies. As mentioned earlier, the Border Commission viewed the early wave of Khmer Rouge territorial aggression as a ploy to gain leverage in tough negotiations.

On the domestic front, Hanoi's leaders were profoundly preoccupied with preparing for their first FYP (1976-80) after unification, and aid from both the Soviet Union and China was deemed critical to its success. In due course, Hanoi made concerted efforts to steer its foreign policy clear of entanglement in the rivalry between its two great power patrons in 1976-77. Maintaining its independent foreign policy orientation, or at least the appearance of it, in the new stage of its socialist revolution was of paramount importance because it allowed Hanoi to more flexibly address its most pressing concerns, that is, economic recovery and modernization, and a socialist transformation of newly liberated southern Vietnam. For a strategic reason, Hanoi preferred to negotiate rather than escalate border conflicts with the Khmer Rouge leadership, which had already received significant support from China right after it toppled the US-backed Lon Nol regime in April 1975. In July 1975, the Vietnamese MOFA circulated among the top leaders a report on foreign affairs, revealing Vietnamese diplomats' frustration and confusion about how best to respond to the contradiction between the DK regime's desire to strengthen relations between the two countries and its increasing military aggression along the border. 

After a series of failed negotiations over border disputes in late 1976 between the Communist Party of Kampuchea (CPK) and the CPV leadership, the land and maritime dispute escalated into armed conflict, often provoked by the DK. The failure of the negotiations was as much due to the clash between the anti-Vietnamese irredentist nationalism of the Pol Pot regime and the Vietnamese assertion of territorial sovereignty as it was to the legacy of French colonialism, which left the boundary between Cambodia and Vietnam highly contested, with Vietnam gaining large areas of territory at the expense of Cambodia under French rule in the late nineteenth century. In November 1976, the Vietnamese Politburo proposed to use the French preindependence map (drawn prior to 1954) as the basis for delimiting the land and maritime boundaries between Cambodia and Vietnam. The CPK agreed to use it “only as a discussion document.”40 There were three major problems with the French map. First, certain portions of the border were not clearly drawn or demarcated. Second, there were a number of major discrepancies between the French map and French documentary records. Third, in the border regions along rivers, there were large discrepancies among the map, documentary records, and the reality of each side’s territorial control. These three problems left ample room for different interpretations supporting each side’s position. This Vietnamese internal record underscores the centrality of Khmer Rouge nationalism—that is, the loss of Mekong Delta (Kampuchea Krom) territory to Vietnam at the hands of the French colonialists and royal and feudal Khmer authorities. 

After 1975 Vietnam desired border security with Laos and Cambodia in order to develop its New Economic Zones, and Khmer Rouge attacks and Vietnamese refugees were disruptive to its socialist economic development plan.42 This does not diminish the fact that the border dispute between Cambodia and Vietnam was a serious and complicated issue to which Vietnam partly contributed.

To the Vietnamese, the DK regime's preference for the use of force over bilateral negotiations was puzzling given their military superiority, and the only logical explanation for the Khmer Rouge's aggressive behavior pointed to Chinese ambitions. To the Khmer Rouge, this was a preventive war waged to reclaim large regions occupied by its historic enemy, Vietnam, while Vietnam A turning point in Khmer Rouge-Vietnamese relations came in 1977 as armed conflict between DK and Vietnam escalated rapidly toward all-out war. Armed clashes along the border—the majority of them initiated by the Khmer Rouge—increased rapidly from 174 in 1975 to 254 in 1976, 1,150 in 1977, and 4,820 in 1978.48 All border negotiations with China throughout 1977 were futile, and armed clashes along the northern frontier also increased exponentially in the second half of the year.49 Since the beginning of the year, relations between Vietnam and its neighbors China and Cambodia had deteriorated on all fronts; but, most notably, the open conflict between Vietnam and Cambodia had deteriorated on all fronts in mid-1977 turned into war by the end of the year. Why did Vietnam decide not to invade Cambodia in late 1977? Internal records of the Vietnamese government reveal that a cluster of issues, including Vietnam's fear of invasion by China, its declining military strength, and the growing economic crisis, along with dwindling Soviet economic and military aid, dissuaded Hanoi from launching a full-scale invasion at that time.

Throughout a full-scale invasion economic and military aid, dissuaded Hanoi from launching a full-scale invasion at that time.

Throughout 1976, Hanoi informed Moscow with great confidence of its ability to make positive changes in its relations with China, as it had done with Laos, bringing the latter out of China's orbit.50 In July, in a conversation with Soviet ambassador B. Chaplin, the Vietnamese deputy minister of foreign affairs Hoang Van Loi declared that the Vietnamese leadership “deemed it necessary  to have patience and work towards gradually strengthening its influence in Cambodia.51 In the meantime, Hanoi attempted to demonstrate its good will toward DK through its emissary in Phnom Penh, Ambassador Pham Van Ba. In November 1976, at Ambassador Ba’s insistence, the Ministry of Health was authorized to send help to the DK regime to combat widespread malaria among the Cambodian populace. On November 13, the DK Ministry of Foreign Affairs received antimalaria drugs at the Vietnamese embassy but refused to allow Dr. Nguyen Tien Buu, deputy director of the Anti-Malaria Institute at the Vietnamese Ministry of Health, and his associates to leave the embassy compound to train DK doctors.52 Considering the DK regime’s vigilance regarding Vietnamese spies, preventing Vietnamese officials from venturing into DK society was hardly surprising. Although Ambassador Ba hailed the delivery of the drugs as a step toward improving relations with DK and thanked the Vietnamese leaders for acting on his recommendation, Hanoi’s leaders were far less impressed with the result of the mission.

Hanoi's strategic patience and hope of bringing DK into a joint effort to solve the border issue ended after Hoang Van Loi's confidential visit to Phnom Penh in February 1977. Pol Pot declined his proposal of a summit of top Vietnamese and Cambodian leaders.53 Instead, the major Khmer Rouge attack on Vietnam on April 30 shook Hanoi's leaders out of their complacency as the Khmer Rouge overran Vietnamese border defense forces and penetrated deep into Vietnamese territory. Hanoi also knew that the Chinese were training and arming Khmer Rouge troops and building roads and military bases, including an air force base in Kampong Chhnang Province, from which planes could reach Ho Chi Minh City in half an hour.54 The reason why the Vietnamese were ill prepared to mobilize an effective military response to the Khmer Rouge attacks goes beyond Vietnam's complacency toward the Khmer Rouge. The most plausible explanation can be found in Vietnam's economic crisis of 1977-78.

The Impact of the Economic Crisis on the Military, 1977-78

Since 1975 Hanoi had relied on diplomacy and bilateral negotiations at the party level to solve its territorial disputes with neighbors Cambodia and China as it strove to forge peaceful border relations with its neighbors so that it could focus on its top priority: economic recovery and the socialist transformation of southern Vietnam. Throughout 1976 Hanoi's confidence in the possibility of resolving the border dispute with the DK leadership through negotiations and goodwill remained very strong. General Secretary Le Duan ignored local authorities' reports that the Khmer Rouge was escalating its attacks on Vietnam with division-level forces.55 In its internal report, the MOFA still referred to DK leaders as "comrades."56 In 1976 Vietnam did not position regular troops along the Cambodian-Vietnamese border, and the majority of Vietnamese troops were ordered to carry out economic duties outside their headquarters. 

The first large-scale Khmer Rouge offensive in Vietnam, launched on April 30, 1977, forced the Vietnamese to acknowledge the bitter reality of the Khmer Rouge military threat and the fact that Vietnam's superior military strength would not deter it. When the DK forces launched major attacks that day, the commander of Military Region 9, General Le Duc Anh, hastily reassembled Division 330 and prepared for combat.58 Given its superior force, Hanoi was astonished that the Khmer Rouge had the audacity to attack Vietnam. The only logical explanation it saw for the continued provocation against Vietnam was China's military support of the Khmer Rouge.

While Hanoi's leaders had proudly shared their anti-US resistance lessons with other countries around the world after 1975, the Vietnamese military was in disarray just a few short years after unification and lacked the strength and discipline for an all-out invasion of Cambodia, especially given China's backing of the Khmer Rouge. As Hanoi prepared its military to crush the Khmer Rouge in the first half of 1977, it discovered many serious issues that had weakened its military strength since the unification of northern and southern Vietnam. In January 1977, the Politburo ordered the CMC to conduct a six-month assessment of military preparedness. On August 28, General Chu Huy Man, deputy secretary of the CMC and a Politburo member, submitted a report on a fact-finding mission to the Politburo and the secretariat of the Party Central Committee. Based on a meticulous study and during the first half of 1977, the report delivered an alarming conclusion to the Vietnamese leadership: "Progress with our war preparedness on all fronts for the past six months fell significantly short of the actual capacity of our armed forces, and some other problems have become very serious. For example, our deployment of troops remains slow and ineffective, and our military strength has been eroded by our troops' weak discipline and sluggish performance. So, as Vietnam was facing the Sino-Khmer Rouge alliance, a series of early military clashes with Khmer Rouge forces in the spring of 1977 raised long-term concerns about Vietnam's lack of military preparedness for war.

When the Khmer Rouge launched its offensive on April 30, a vice-minister of national defense, who served on the CMC, was dispatched to assess the military situation on the frontlines and provide guidance on border defense to the commands of Military Regions 5, 7, and 9 in the south. The lack of war preparedness among local armed forces and their poor combat performance were appalling to military leaders in Hanoi. In a series of counteroffensives against Khmer Rouge forces, regular Vietnamese troops also performed poorly, ranging from slow mobilization, erroneous assessment of the enemy’s strength, and ill-conceived strategies to poor management of weaponry equipment and ammunition storage.60 In May, the CMC issued an order to immediately correct these shortcomings as it ordered a general mobilization of troops in the south, and by July all troops were put on full alert for counteroffensives. Military Regions 7, 9, and 5 and the Third and Fourth Army Corps of the PAVN were already engaging the Khmer Rouge along the border. The army quickly turned to increased political training and strict military discipline to raise morale. In 1977, now without substantial economic and military aid from the Soviet Union, the economic situation within the Vietnamese military went from bad to worse.

Certainly war weariness among the troops played a role in Vietnam's post-war lack of combat readiness, but it was economic hardship, worsened by the lack of foreign aid after 1975, that compelled Hanoi to direct the army to engage in economic work, which in turn undermined its military strength and combat readiness, especially in the south, where the economic crisis took a major toll on the military. In October 1976, the Politburo issued a resolution on the role of the military in building the economy to advance Vietnam's new revolutionary mission of socialist reconstruction throughout the country. The wartime slogan "Everything for the front" (Tat ca cho tien tuyen) was replaced with the peacetime slogan "Everything for production, everything for building socialism" (Tat ca cho san xuat, tat ca de xay dung chu nghia xa hoi).62 In other words, the army was instructed to combat economic hardship, the new enemy after the war, by doing work such as clearing farmland, planting crops, and raising livestock and fish.

As laid out by the Fourth Party Congress in December 1976, Hanoi set two postwar national priorities: (1) economic recovery, modernization, and the socialist transformation of southern Vietnam; and (2) defense of territorial sovereignty. Certainly the first priority was the most important national goal. No Vietnamese leader emerging from this congress could have anticipated a major war with Cambodia and China in late 1978 and early 1979, let alone a war that would last a decade. The Politburo attached paramount importance to economic reconstruction and modernization in the first FYP (1976-80) and socialist transformation in newly liberated southern Vietnam. It began deliberating in earnest and drawing up its FYP in mid-1975, shortly after the Republic of Vietnam fell on April 30, enlisting hundreds of able and highly experienced economists and scientists to participate in the process and establishing twelve economic and scientific research committees to study the most critical areas of the economy. A draft FYP was circulated for in-depth discussion at the Council of Government. It was then reviewed and commented on by the Politburo on three separate occasions. In October 1976, the final version was presented to the Twenty-Fifth Conference of the Party Central Committee.63 At the end of November, the Politburo assigned deputy prime minister and Politburo member Le Thanh Nghi the task of preparing a concise presentation to relay key points of the FYP to party members at the Fourth Party Congress to ensure that all of them would have a good grasp of party policy in the new revolutionary age.

In December the Politburo set four main national goals: (1) stabilize and improve the standard of living, (2) build the economic and technical foundations of socialism, (3) train and improve the quality of government officials and workers, and (4) strengthen national defense. As a top strategic priority, the party was determined to solve the food crisis by 1978, or at the latest by 1980 (the end of the FYP), and it called on all party members, from the central government to local jurisdictions, as well as the masses, to help achieve this mission.

In the spring of 1977, the party launched a national campaign encouraging people to compete in building socialism and working to boost productivity while saving whatever they could and contributing any production surplus to the government.

While the government focused on solving the economic crisis, Vietnam's military strength rapidly eroded. The Politburo tasked the army with both building the economy and defending national sovereignty after the Fourth Party Congress. In 1977 the MOD planned to release twenty thousand soldiers from the army (and at least an additional eighty thousand by 1980) while it reassigned a large portion of the armed forces to do economic work.67 In 1977 the armed forces at all levels were ordered to engage in the economic mission. By mid-1977, the army reportedly had cleared new farmland and planted 20,000 hectares of food crops (60 percent of the plan) and raised 50,000 pigs, 20,000 cows and buffaloes, and nearly 140,000 chickens. It had farm-raised at least 6 million fish and created its own fishing units.68 Its logistical department itself became a semi-ministry as the army's economic role was markedly expanded in the postwar era. But the CMC assessment report made a bleak observation: "Although the army leadership paid close attention to economic tasks, the living conditions of our troops in many places continue to be poor and will worsen due to the economic difficulties our country is facing today."69 On top of its economic  Hardship, the Vietnamese army had to help the Laos People's Democratic Republic (LPDR) in Laos to strengthen its national defenses by dispatching Vietnamese military advisers, as requested by Laos; building defense projects; accepting Laotian soldiers for military training in the Vietnamese military academy; and providing military aid as pledged in a bilateral agreement signed in May 1976.

Nothing is more demoralizing to rank-and-file soldiers, perhaps, than a government's inability to provide proper burials for soldiers who die defending the nation. In the south, when a soldier died the government offered a one-time state gift of 120 VND, as mandated by government Directive 10/ND, dated June 18, 1976, to the soldier's family to pay for burial. This amount fell far short of the actual cost of a proper burial, as the cost of new clothes for the deceased alone ranged from 280 to 700 VND. Facing growing criticism from veterans' families, in May 1977 the Ministry of Veteran and Social Affairs sent an urgent request to Prime Minister Pham Van Dong urging the government to increase the subsidy to families of deceased soldiers and government employees.71 Deputy Prime Minister Pham Hung instructed people's committees at the provincial and city levels to urgently address the issue, but the subsidy remained unchanged. Thus the impact of Vietnam's severe poverty further contributed to the decline in soldiers' morale and discipline. For the second half of 1977, the CMC proposed to concentrate on elevating the war readiness of army units along the border and on islands; speeding up the implementation of economic tasks assigned by the Politburo; improving logistics, especially securing enough food for the troops; and enhancing military discipline and political indoctrination in the army. 

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While Hanoi was caught off guard by the scale of the Khmer Rouge attacks, it was not entirely unprepared. In late 1976, Hanoi had begun to increase its military presence along the border with Cambodia.59 By the end of 1976, Vietnam had deployed two divisions along the border with Cambodia, and by the end of 1977, it had deployed three divisions.60 Hanoi's response to the Khmer Rouge attacks was a combination of military and diplomatic measures. Militarily, Vietnam increased its troop presence along the border with Cambodia, launched counterattacks, and initiated a series of offensives against the Khmer Rouge in 1978. Diplomatically, Hanoi sought to isolate the Khmer Rouge internationally and to gain support from the Soviet Union and other socialist countries.

In the meantime, Vietnam's economic situation worsened. The country was already facing a severe economic crisis due to a variety of factors, including the collapse of the Soviet Union, the end of the Cold War, and the withdrawal of Soviet aid. The war with Cambodia further exacerbated the crisis, diverting resources away from economic development and social welfare programs.

Despite these challenges, Vietnam persisted in its military campaign against the Khmer Rouge. The Vietnamese military ultimately achieved a decisive victory, forcing the Khmer Rouge to retreat from the border areas. However, the war had a significant human and economic cost for Vietnam.

When the Khmer Rouge launched its offensive on April 30, a vice-minister of national defense, who served on the CMC, was dispatched to assess the military situation in the border provinces. The report concluded that "the military units were not ready to fight."61 The report noted that the units were poorly equipped, lacked ammunition, and were short of supplies. The soldiers were poorly trained, and the officers lacked combat experience. The report also noted that the morale of the troops was low, and many soldiers were homesick and wanted to return to their families.62 This report confirmed the Politburo's worst fears about the state of the Vietnamese military.

The Vietnamese military's weaknesses were a result of a number of factors, including the long war with the United States, the rapid demobilization of troops after the war, and the focus on economic development. In addition, the Vietnamese military had been plagued by corruption, nepotism, and inefficiency.

Despite these challenges, the Vietnamese military was able to mobilize and eventually defeat the Khmer Rouge. However, the war was a costly one for Vietnam, both in terms of human life and economic resources. The war also had a significant impact on Vietnam's domestic politics, leading to a period of political and economic instability.

The Vietnamese military's experience in the war with the Khmer Rouge has had a lasting impact on Vietnam's military doctrine and strategy. The war highlighted the importance of maintaining a strong and well-prepared military, even in times of peace. It also underscored the need for a flexible and adaptable military strategy that can respond to a variety of threats.

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Hanoi was also concerned about the depletion of mid-level leaders within the army. While the number of high-ranking military officers increased significantly, accounting for 25 percent of the armed forces, infantry company commanders accounted for only 4 to 5 percent in 1977. There were too many generals and not enough well-trained mid-level officers to lead combat operations. 

Vietnam also had to fulfill its international socialist duty of providing military aid and training to Laos,74 which further drained the army's human and material resources. From the perspective of the CMC, the shortage of mid-level military leaders also contributed to the poor quality of political education and military training for new recruits from remote regions in newly liberated southern Vietnam.75 As a result, the report concluded:

• Our soldiers [in the south] are not yet well equipped with correct ideological weapons to fight the new kinds of enemies and [perform] the twin tasks of building the economy while defending our nation. The majority of our troops lack political awareness, the will to fight, and the determination to overcome

difficulties; many try to avoid tedious work and evade their duty of building the economy and contributing their labor to boost production. A great amount of manpower has been wasted. The widespread violations of military discipline and the phenomenon of abandoning military duties at the local level need our attention.⁷⁶

It is clear that Hanoi’s military leaders were less than impressed by the combat readiness and performance of their troops, especially local forces in the south, and they only came to the realization in mid-1977 that much work remained to be done to prepare the army for war, especially in the event of a full-scale invasion of Cambodia and a possible military confrontation with China on the northern front. In the second half of 1977, the CMC, as reported by General Chu Huy Man to the Politburo on August 31, 1977, issued a resolution focusing on (1) enhancing the war readiness of Vietnamese soldiers, especially those who were defending border regions and islands (in the South China Sea), (2) quickly performing the economic tasks entrusted to troops by the Politburo, and (3) rapidly drawing up a military plan for 1978 and a long-term plan for building up the military and strengthening national defense.⁷⁷ As the military leaders were preparing their troops for war, Hanoi chose to launch major counteroffensives to send a clear message to the Khmer Rouge that military confrontation with Vietnam would not be in its best interest, hoping to force it into more fruitful negotiations on the border issue. But the Khmer Rouge was undeterred by the Vietnamese counteroffensives, which penetrated thirty kilometers into southern Cambodia in May and June, and it continued to attack Vietnam, killing Vietnamese citizens and plundering their property. Hanoi’s leaders saw this as a defiant response by a radical anti-Vietnam Khmer Rouge regime, which remained characteristically antagonistic and merciless toward Vietnamese people along the border in spite of Vietnam’s goodwill.

  The Economic and Security Nexus and the Soviet Factor

In 1977 Hanoi made a last-ditch effort to maintain amiable relations with Beijing in the faint hope that it would renew the aid programs that Vietnam desperately needed to support its FYP and to enlist China’s support in putting pressure on the Khmer Rouge regime to cease its attacks along the border. Although Hanoi tilted closer to the Soviet Union, it refrained from officially joining the Soviet-dominated COMECON simply because an open alliance with Moscow would certainly antagonize Beijing.⁷⁸ In a demonstrative display of national independence and a play for capital and technology from the West to support its economic agenda, Hanoi sought to speed up normalization of relations with the United States and to diversify its economic relations with a number of capitalist states.⁷⁹ The head of the US Division of the MOFA, Tran Quang Co, who participated in the first round of negotiations for normalization of US-Vietnamese relations on May 3, 1977, recalled in his memoir that Hanoi’s demand that Washington pay war reparations of US$3.2 billion as an important precondition for normalization was problematic for the Carter administration because the US Congress would oppose such a demand. Because of that demand, in Co’s view, Vietnam missed an important opportunity to normalize relations with the United States in 1977.⁸⁰ Hanoi did not abandon this demand until September 1978, preventing Washington from moving toward normalization of relations until it was too late because Hanoi’s intentions vis-à-vis Cambodia and the Soviet Union were clear by that time. The Carter administration saw American national interests as lying with China as a way to contain Soviet ambitions in Southeast Asia.⁸¹ Thus, by mid-1978 Hanoi had no choice other than joining the Soviet-led COMECON, and it signed a military pact with Moscow to ensure the flow of economic and military aid from the Soviet Union and the rest of the Soviet-led socialist bloc to address both its economic and political crises at home and the security threats posed by the anti-Vietnam alliance between China and DK in Cambodia.

Evidently, the Vietnamese leaders decided to join COMECON only after Beijing's intention to oppose Vietnam was clear to them. On July 20, 1978, Politburo member, deputy prime minister, and chairman of the State Planning Committee Le Thanh Nghi told the Council of Government, "As China has openly opposed us, the Politburo saw the need to officially join the Council for Mutual Economic Assistance to demonstrate our stance and seek support and assistance from the Soviet Union. This has become necessary."82 Nghi further reasoned, "Our membership in COMECON has increased the political influence of the Soviet-led socialist camp... [as well as] the Soviet Union's trust [of Vietnam] and our closeness with the Soviets and other members. With this our country will win other socialist countries' accord, support, and assistance to us in all fields."83 The Soviet Union and other COMECON members quickly pledged to replace China's aid programs. Hanoi wasted no time in making a request to COMECON for assistance in a number of important areas of critical need in order to (1) expedite the design and construction of seven industrial projects pledged by COMECON, (2) speed up mechanization of Vietnam's agriculture, and (3) import modern technology and equipment to modernize Vietnam's economy.

agricultural sector, (3) build a railroad connecting Hanoi and Ho Chi Minh City, and (4) continue to provide industrial equipment and parts to complete forty projects for which China had terminated aid.

 By early 1978 Vietnam was in a deep economic crisis that poisoned the political atmosphere and aroused popular resistance, alarming the CPV. Without US$3.2 billion in reparations from the United States and 1.9 billion RMB in aid and loans from China, Vietnam's first FYP was stalled. The worsening economic crisis precipitated a corresponding sociopolitical crisis across the country. In the south, Vietnam lost the $1 billion per year aid package the United States had provided to the Republic of Vietnam, leaving a great financial burden for the victorious Communist government.85 Le Thanh Nghi, on several occasions lamented that the DRV (and by extension the later SRV) had lost US aid to the government of the Republic of Vietnam. Since the burden of postwar reconstruction in southern Vietnam after 1975 was enormous, Hanoi's leaders believed that they were entitled to US aid for war reparations as a condition of normalization of US-Vietnam relations in 1977-78.

On December 6, 1977, Le Thanh Nghi lamented, “While the imbalance of our economy since the war ended has not yet been resolved, we have to rely on our own strength to meet a great domestic demand for food, raw materials, spare parts, industrial equipment, and hard currency to cover our large trade deficit.”86 On an optimistic note, Nghi emphasized the potential of Vietnam’s national resources, including five million hectares of farmland (potentially to be increased to eleven million by 1980), a large amount of rich forestland, and untapped maritime resources and freshwater fishing. In addition, Vietnam had a large labor pool of 22 million people and a modest number of educated people (3,000 cadres with higher education degrees, 160,000 with university degrees and 350,000 with high school diplomas), a million technicians, and tens of millions of farmers and experienced leaders of cooperatives. 

The economic situation continued to spiral downward in the spring of 1978. In his address to the Third Conference of the Central Committee of the CPV, Le Thanh Nghi presented an extraordinarily bleak assessment of Vietnam’s economic crisis: “Our national economy is in a situation in which we cannot produce enough food to eat (lam khong du an), earn enough income to cover our expenses (thu khong du chi), and export enough to cover our imports (xuat khong du nhap).”88 As the FYP was on the verge of collapse, Nghi attributed the worsening crisis to the loss of foreign aid in the amount of US$1.5 billion per year (a $1 billion in the south and 400 to 500 million rubles in the north), leaving a large gap in the foundation of the national economy.89 In addition, Vietnam suffered a severe drought in 1977, increasing the severity of the food shortage as The country lost helf of the agricultural harvest that year except in the Mekong Delta .

In 1978 the economic crisis had serious political consequences for the party-state, threatening to escalate into a breakdown of the sociopolitical order with a damaging impact on the government’s legitimacy. During the crucial years 1977-78, the Central Committee of the CPV appeared to lose control over local affairs and was blindsided by many self-serving local party officials. Rampant corruption and abuses of power at the local level profoundly worried Hanoi’s leaders. From January to September 1978, the General Prosecutor arrested 1,735 “so-called”—a euphemism for “executed”—717 individuals from the district authority level and “eliminated” at the district authority level and “eliminated”—a euphemism for “executed”—717 individuals from the state apparatus. In addition, from September to December, the General Prosecutor was authorized by the Politburo’s Resolution 228, reinforced by the prime minister’s Directive 159, to investigate more than 6,000 government officials who were suspected of having committed economic crimes. A total of 51,892 complaints against government officials were filed with the General Prosecutor, indicative of rising popular resistance to the party-state. Civil disobedience in the form of refusing to relocate to the New Economic Zones, avoiding military duty, or simply disregarding state rules and regulations was reportedly widespread. In 1978 alone, the bureau investigated a total of 28,342 cases of violations of state laws, a sharp increase of 46 percent compared to 1977. Three million people were unemployed in the south alone.92 The political crisis, intensified by the socioeconomic crisis, Hanoi recognized, had the potential to explode into social upheaval, particularly in the south, giving more ammunition to enemies inside the country (e.g., resisters from the Thieu regime and the United Front for the Liberation of Oppressed Races, better known as FULRO, a guerrilla group fighting for autonomy for the Montagnard tribes) and outside it (Khmer Rouge and Chinese reactionaries) to exploit and expand internal instability and undermine the party-state. It was overwhelmingly clear to the Hanoi leadership by 1978 that many party officials at the local level were undermining party policies in the pursuit of personal gain, generating increasingly tense relations between the populace and the party-state. But Hanoi's worst fears of dire political consequences would be realized if it failed to find a solution to the intensified crisis soon.

While Hanoi faced domestic crises in 1977, the external threat to Vietnam's national security was gathering strength as 1978 approached.

If in 1976 Le Duan could afford to ignore Khmer Rouge attacks along the southwestern border out of confidence in the superiority of Vietnamese military strength as a deterrent and in diplomacy as a gesture of goodwill and patience, he came to full realization in 1977 that the major attacks by Khmer Rouge forces had been ordered and planned by the DK leadership. Hanoi's leaders concluded that the Khmer Rouge regime's tenacious defiance indicated that it would continue its attacks on Vietnam unless the regime was toppled. After personally touring the battlefield along the border after the April 30 Khmer Rouge attacks, Le Duan came to the conclusion that Pol Pot's explanation that previous attacks were launched by insubordinate or undisciplined local commanders was in fact a CPK strategy intended to deceive the Vietnamese leaders into believing that the conflict could be resolved at the party level.93 When Vietnamese ambassador Pham Van Ba raised the issue of border conflicts with Pol Pot on September 2, 1977, the latter shifted the blame to "enemies within the Party ranks."94 Hanoi had had enough of Pol Pot's excuses by this time. But as it contemplated a decisive military response to eliminate the DK threat, it feared military retaliation by Beijing from the north. At the end of 1977, during his visit to the southern region, in response to a group of confused local officials who frankly criticized Hanoi's feeble response to the Khmer Rouge attacks and brutal killings of Vietnamese people along the border, Le Duan remarked, "Comrades [leaders] have pointed out the situation that has puzzled the whole country. We [leaders] have had a lot of headaches and lost a lot of sleep over this issue. The issue is not DK and Pol Pot but those who are behind them [referring to China]. We have a powerful army; they cannot resist us, but if we attack them, China will attack us. If we do not take over Cambodia, China will not attack our country."

Le Duan's view was grounded in Vietnam's territorial dispute with China. By mid-1977, the dispute had turned into open armed conflict and all negotiations at the provincial level had failed. The tension gave way to a sense of relief, however temporary, as Beijing suggested that top-level negotiations should take place at the end of the year, offering Hanoi hope for a peaceful resolution of the conflict.96 It was not unreasonable for Hanoi to believe that a resolution of the border conflict with China would lead to a renewal of Chinese aid to Vietnam. In November Vietnamese Deputy Prime Minister Le Thanh Nghi sent a letter to Chinese Vice-Premier Li Xiannian requesting that China provide material aid and consumption goods worth 1.1 billion RMB on credit and a loan of 900 million RMB without interest over the period of three years from 1978 to 1980.97 According to Le Duan's assistant, Tran Phuong, in late 1977 when the Vietnamese army launched a major offensive that penetrated thirty kilometers into Cambodian territory in the southwest,98 it captured military documents that confirmed Hanoi's suspicion that China was behind the Pol Pot regime's aggressive behavior toward Vietnam. 

At the end of 1977, the Vietnamese Party Central Committee declared war on the Pol Pot regime and began to view China as enemy.100 Only then did Hanoi begin to place an emphasis on enhancing the country's strategic relations with extraregional powers, especially the Soviet Union and the United States. Hanoi repeatedly sent high-ranking officials to Phnom Penh to try to bring DK in line with its ideology and away from China’s, but this failed utterly. After a chain of increasingly hostile actions by Beijing, combined with its cold reception of Vietnamese leaders, Hanoi concluded that China was intent on weakening Vietnam.

Through a series of economic negotiations and exchanges of letters between top leaders of the two countries in the second half of 1975, Beijing made it clear to Hanoi that from 1976 onward China would no longer provide nonrefundable aid to Vietnam. To Vietnam's further disappointment, China only agreed to provide an interest-free loan of 100 million RMB (roughly US$50 million) to import consumption goods from China in 1976 and refused to negotiate a long-term trade agreement as Hanoi repeatedly requested.101 Beijing also postponed the delivery of materials and equipment for a total of eighty economic projects, which would significantly undercut Vietnam's FYP.102 In late 1975, Beijing also cut off military aid to Vietnam, including a large amount of military supplies.103 On December 2, 1976, Vietnamese deputy prime minister Do Muoi stopped over in Beijing on his way to Moscow, and the Politburo instructed him to stay two additional days to persuade Beijing to provide additional aid to Vietnam. Chinese Vice-Premier Gu Mu, a top leader in economic circles in the Chinese government, again pointed out China's own economic difficulties and its obligation to provide aid to sixty other countries.

The mood in Hanoi had taken on an increasingly apprehensive edge as Beijing entered into an extraordinarily public feud with Hanoi in defense of the Khmer Rouge after late 1977, and its condemnation of the Vietnamese military response as incursions into Cambodia had intensified. On June 2, 1977, General Vo Nguyen Giap stopped in Beijing on his way back from Eastern Europe, but his counterpart, the Chinese minister of defense, did not show up to receive him at the airport. Giap, a great general and the face of the Vietnamese army, was reportedly furious during his entire stay in China. As the Vietnamese ambassador to China, Nguyen Trong Vinh, recalled, “China treated General Giap’s delegation with disrespect… On the train back to Vietnam, the Chinese used rice bowls with chipped edges to serve the Vietnamese delegation.”105 On June 10, in front of other high-ranking officials on both sides, Chinese Vice-Premier Li Xiannian and Vietnamese Prime Minister Pham Van Dong had a heated exchange over who had caused the deterioration of Sino-Vietnamese relations. Vice-Premier Li chastised Pham Van Dong for not honoring his own 1958 letter, which purportedly recognized China's sovereignty over the Spratly and Paracel Islands in the South China Sea.106 During Le Duan's visit to Beijing on November 20-23, he also received a cold reception from the Chinese leadership. Deng soon felt Deng Xiaoping's hostility,107 as Deng did not come to welcome Duan at the airport.108 Deng's indifference to Le Duan at that time was taken as a sign that Sino-Vietnamese relations had gone from bad to worse, and Hanoi's leaders were bracing for some kind of confrontation and certainly more Chinese pressure as Deng consolidated his power at the helm.

The Decision to Invade Cambodia and the Soviet Factor

Rather than demonstrating its generosity and willingness to replace China in supplying aid to Vietnam, Moscow saw these events as an opportunity to put more pressure on Vietnam to join COMECON and eventually draw Vietnam into the Soviet orbit. On October 27, 1977, Soviet ambassador Chaplin came to the office of the Foreign Affairs Committee of the Party Central Committee to inform Xuan Thuy, a top Vietnamese diplomat, of the Soviet government's reply to Pham Van Dong's request for Soviet military aid to Vietnam for the period 1976-80.109 Moscow pledged far less than the amount of military aid Hanoi had requested. For example, it agreed to provide only two patrol boats and six fishing boats converted for use as patrol boats, three land-based radar systems, and other less-valuable items. Notably, Moscow did not honor Hanoi's request for major state-of-the-art weaponry for its air force, navy, and infantry, including twelve MiG-21MF fighter jets and two MiG-21US training jets, two missile ships (183R type) equipped with three missile systems, two submarine hunter ships (Gorista type) with three torpedo systems, two fully equipped survey ships, twenty attack boats, and three bridging tanks.110 After Xuan Thuy briefed the Politburo on the results of his meeting with Ambassador Chaplin, there was a strong sense of apprehension and anxiety among senior Politburo members about what they saw as the Soviets' opportunistic behavior. But Moscow's intended message was clear: until Vietnam joined COMECON and sided with the Soviet Union, Hanoi would have to make do with whatever aid it decided to deliver. In the spring of 1978, Hanoi's leaders felt isolated as they strove to implement their first FYP after the 1975 unification while the two-front military threat to Vietnam's territorial sovereignty from the Sino-Cambodian alliance was omnipresent on both the northern and southwestern frontiers.

Nonetheless, in January 1978 Hanoi adopted a political-military solution to the Cambodia problem. According to Chanda, it was a Soviet general who suggested in January that Vietnam "do a Czechoslovakia" in Cambodia.111 But Vietnamese internal reports corroborate Morris's assertion that Moscow had little influence on Hanoi's marked shift from counteroffensives in 1977 to a full-scale invasion and occupation of Cambodia in early 1978.112 Although the Vietnamese welcomed Soviet support for the invasion, its leaders knew that the Soviet Union would not commit ground troops other than military advisers.

The Conservative and Military Leaders at the Helm

As early as January 1978, the CMC proposed decisive military action to overthrow the Pol Pot regime and put an end to DK attacks on Vietnam. To rally the population around a new regime and justify the invasion, Hanoi saw the need to create a Khmer revolutionary front. On April 21, the Vietnamese Politburo issued Resolution 34 establishing Committee 10, headed by Vice-Minister of Defense Tran Van Quang. The committee was given two specific tasks: (1) recruit revolutionary armed forces among Khmer refugees and defectors and (2) research and advise the CMC on the plan to assist the Khmer revolutionary army. On May 12, at Camp 977 in the Thu Duc district of Ho Chi Minh City, Hanoi established its revolutionary army, the Kampuchean United Front for National Salvation (KUFNS), and appointed former Khmer Rouge military officer Hun Sen commander of its first unit. This unit consisted of only 125 officers and soldiers.

In January, as the Vietnamese army pounded the DK forces, the Chinese ambassador in Hanoi condemned “Vietnam's invasion of Cambodia and accused Vietnam of killing Cambodians and plundering Cambodians' properties” and personally asked the Vietnamese government to withdraw all troops from Cambodian territory.115 But by this time Hanoi was oblivious to Beijing's condemnation.

In January the Border Commission of the Party Central Committee informed the Politburo that during a series of border negotiations in 1976-77 Beijing’s main intention was to weaken Vietnam. “China wants to take over our territory where there are rich natural resources and islands of strategic importance to its military, undermine our ability to develop our economy, obstruct our cooperation with the Soviet Union and our neighbors, and prevent us from opening and developing the border region.”116 On March 23, 1978, Vice-Minister of Foreign Affairs Phan Hien, who headed the Vietnamese border negotiation team, concluded that “future negotiations would be in vain” because China was continuing to pressure Vietnam to accept its positions and recently had brought up the border conflict between Vietnam and Cambodia during negotiations over territorial disputes between China and Vietnam.117 Moscow was kept informed all along about the results of these negotiations. In February the Ministry of the Interior reported a sharp increase in Cambodian and Chinese incursions into Vietnamese territory along the southwestern and northern borders, generating the perception in Hanoi that Vietnam was under siege.

At a major conference on January 26, 1978, as the CMC pushed for an invasion of Cambodia, the MOFA leadership proposed to launch a diplomatic offensive to justify any military interventions in Cambodia. It put forth three scenarios: (1) Cambodia continues attacks in Vietnam, anti-Vietnamese nationalism and public denunciation of Vietnam rise, and Cambodia refuses to negotiate; (2) Cambodia continues all these activities while negotiating with Vietnam, but negotiations fail; and (3) Cambodia ceases all military attacks along the border, negotiates with Vietnam, and takes steps to resolve the border problem.

In the MOFA's assessment, the situation was evolving in the direction of the first scenario because the DK leadership was not intimidated by Vietnamese counteroffensives into cooperation and compromise at the negotiation table. The MOFA further reasoned that if Cambodia were to be soundly defeated by military force an internal split within the DK leadership would occur, for it would realize that its policy of relying on China to militarily oppose Vietnam was doomed to fail. Cambodian leaders would be condemned by their own populace—possibly by means of an internal uprising—as well as by world opinion. And they would be forced to negotiate to buy time to restore domestic order. The situation would evolve according to the second scenario: futile negotiations. However, if DK suffered a devastating military and political defeat, it would be forced to give up its belligerent policy toward Vietnam, and if China faced more internal struggles among competing factions in its domestic politics, became isolated internationally, especially within the socialist bloc, because of its support of anti-Vietnamese Cambodia, and failed in its attempt to drive a wedge between Vietnam and Laos, then the third scenario would develop.

Although the MOFA agreed with the CMC that the third scenario would be the best option, it cast doubt on Vietnam's economic and military ability to successfully carry out an invasion of Cambodia and engage in nation building there without the military, economic, and political backing of the Soviet bloc.

Based on MOFA's rationalization, there were “two scenarios” for Vietnam's policy toward Cambodia in 1978: one was to continue to negotiate with the DK, hoping that the Khmer Rouge would eventually come to the negotiation table, and the other was to prepare for a full-scale invasion of Cambodia.

Based on MOFA's rationalization, it could be argued that Hanoi's "two camps" worldview—that is, the ideological conflict between communism and capitalism—in which victory was shifting in favor of the Soviet bloc, remained influential.123 But such an ideology does not necessarily conflict with Hanoi's  rational decision making. In fact, this ideological underpinning eased Hanoi's decision to join COMECON and ally itself with the Soviet Union by silencing potential resisters and doubters, especially the pro-China faction, within Vietnam's domestic politics, and those economically minded leaders who were concerned about the adverse impact of the war on Vietnam's economy. But if this ideology was a cause of Hanoi's decision to ally itself with the Soviet Union against China, why did Hanoi hesitate until mid-1978 and why did it make a sudden move at that point?

In planning its invasion of Cambodia, Hanoi closely observed the internal struggles in both Cambodia and China, looking for an opportune time to invade. On January 1, 1978, the Vietnamese leadership received an important piece of intelligence reporting that the internal struggle for power between Chinese leaders Deng Xiaoping and Hua Guofeng had intensified.124 In May 1978, Hanoi received news that DK had pulled some of its troops from the border region to quell an internal uprising in the Eastern Zone.125 These were all encouraging signs as Hanoi was preparing for military intervention in Cambodia.

Against this backdrop, the MOFA proposed to launch a diplomatic offensive, far greater than it had done before, to prop up its "self-defense" justification when the military intervention in Cambodia was under way because it recognized that Vietnam was losing in the court of world opinion as it intensified its counteroffensives in Cambodia in the spring of 1978. To the MOFA, the pendulum of world public opinion appeared to be swinging in favor of Phnom Penh's anti-Vietnam propaganda, amplified by Beijing, claiming that "Vietnam has an ambition to establish an 'Indochinese Federation,' orchestrating regime change in Cambodia with the intention of propping up its client state there." 

To disrupt this public perception, the MOFA instructed its diplomatic corps to redouble its efforts to elicit favorable public opinion around the world that would cast Vietnam's military actions as much as possible in the light of self-defense. The rationale, in the words of MOFA officials, was "If Cambodia refuses to negotiate or prolongs negotiations, we will win politically because we will shift world opinion to support our self-defense actions and Cambodia will be more politically isolated."127 It is overwhelmingly clear that by late January 1978 a collective decision had been reached to deal the Khmer Rouge a decisive military blow and follow it with regime change in Cambodia. The MOFA sought to launch another round of diplomatic offensives to justify these military interventions. 

By mid-1978, the economic crisis worsened and there was enough blame to go around all branches of the government. From May 12 to 15, Chairman of the State Planning Committee Le Thanh Nghi, who was deputy prime minister and

Politburo member, presided over a conference on the state of economy with district and provincial leaders. He opened his address to high-ranking party and government officials with a self-critically candid view of the state of the economy: “Now we are facing [economic] difficulty, and it’s going to get worse. It’s partly due to the economic reality, but our shortcomings with regard to economic management and organization are the main cause. All levels of the party and government are responsible for this, and therefore we must face our own shortcomings head on and accept our responsibility. We must not put blame on other people.”

This rare admission of failure by the economic chief of the Vietnamese party and government reflected the severity of the economic crisis in the run-up to Vietnam’s decision to join COMECON in June of that year. This provides another important immediate background to Hanoi’s decision to join COMECON in June and sign a military alliance with the Soviet Union in November 1978.

On the battlefield, from December 1977 to June 1978, 6,902 Vietnamese soldiers died and 23,742 were injured during border clashes with DK forces, and 4,100 Vietnamese citizens were killed or injured in brutal attacks.130 It was not difficult for the Vietnamese government to channel the population's rage into emotional support for a decisive military action against the Khmer Rouge. On November 3, Hanoi officially signed the Soviet-Vietnamese Treaty of Friendship and Cooperation, but the alliance agreement was agreed on in June during which time the Soviet deputy foreign minister, Nikolai Firyubin, made an unannounced trip to Hanoi to smooth out the remaining differences in the draft.131 Hanoi was to decide on the timing of the public announcement of the treaty to deter Beijing from contemplating military action against Vietnam.

Nonetheless, in August, Moscow demonstrated its commitment in material terms. At Hanoi's request, the Soviet Union began an unprecedented airlift and sea transport of arms, including long-range artillery pieces, missiles, and MiG-21 fighter planes to bolster the country's defenses against China.132 On December 23, Prime Minister Pham Van Dong made the case for all-out war against the Khmer Rouge regime and an invasion of Cambodia to the fourth session of the Sixth Plenum of the National Assembly. His entire speech was aimed at convincing his comrades that with the full backing of Soviet political, economic, and military might Vietnam was assured of victory and that China, which he described as a "paper tiger," would not dare attack Vietnam.135 On the same day, a combined Vietnamese force of three army corps and troops from Military Regions 5, 7, and 9 under the command of General Le Trong Tan launched an invasion of Cambodia. But the Khmer Rouge regime was not taken by surprise as it had already withdrawn its major forces westward toward the Thai border. 

The bulk of the documentary evidence reveals that the wider strategic calculations of Vietnam's national security (i.e., its alliance with the Soviet Union to counter the alliance between DK and the PRC and to draw the Soviet bloc's greater assistance to address its domestic economic crisis) in 1977-78 played a more significant role in Hanoi's decision making vis-à-vis Cambodia than either local factors (such as KR border raids) or geopolitical concerns steeped in long-term historical conflict. Vietnam's decision to invade Cambodia was made in the context of domestic and external imperatives in 1977-78, not as a result of its long-standing hegemonism. Certainly, the threat to Vietnam's national sovereignty of the Sino-Khmer Rouge alliance was growing before Vietnam's invasion of Cambodia in December 1978; and the Vietnamese had a strong desire for revenge for the atrocities the Khmer Rouge troops committed against thousands of innocent Vietnamese civilians along the Cambodia-Vietnam border. These factors facilitated Hanoi's decision to invade Cambodia in December 1978, but they were not necessary and are insufficient to explain Hanoi's external and internal motives, that is, to enlist Moscow in an alliance that would preempt China's attacks and attract economic and military aid from the Soviet Union to relieve Vietnam's economic crisis and boost its military strength. The convergence of strategic interests between Vietnam and the Soviet Union explained the formalization of an alliance between them.

In January 1978, the Vietnamese CMC recommended a decisive military intervention and a regime change in Cambodia. Vietnamese leaders made this consequential decision in early 1978 when they were under siege domestically (from the socioeconomic and political crisis) and externally (from the two-front threat of the Sino-Cambodian alliance). Almost all doors were closed around them; they had missed the opportunity to normalize relations with the United States in 1977, and they blamed China for undermining it.

Hanoi's rational calculation of benefits from the Vietnamese-Soviet alliance for Vietnam's national survival against the Chinese threat and alleviation of an economic and sociopolitical crisis alarmingly detrimental to the legitimacy of the CPV were the main drivers of Hanoi's decision to invade Cambodia and form an alliance with the Soviet Union. As a continued revolution by other means, war provided the CPV leadership with the power to extract subordinate and sacrifices to defend the Vietnamese nation and a rationale for subordinating economic development to the priority of national defense. Also revealing is the rising influence of the military-first faction spearheaded by the CMC in the decision-making process as the economy-first faction, including the chairman of the State Planning Committee, Le Thanh Nghi, was largely discredited due to

the worsening economic crisis. This shift was manifested in Hanoi's return to military-security priorities and the Marxist-Leninist "two-camp" worldview in late 1977 and early 1978, ending its earlier attempt to employ a broad-based foreign policy of economic engagement with the West. As I discuss in chapter 3, the military-first priority heightened after China's invasion of Vietnam on February 17, 1979, which suddenly pushed Vietnam to mobilize the entire nation for a two-front military confrontation in Cambodia and against China along its northern border.