8 - Moscow, Beijing, and Détente

Summary

In 1968–73, the Soviet Union and the Peoples Republic of China played crucial military and political roles in the Vietnam War, particularly against the background of larger developments in world politics. The Sino-Soviet split, Sino-American rapprochement, and Soviet-American détente all influenced the North Vietnamese conduct of war. The split made coordination of socialist aid in the second half of the 1960s difficult, but also resulted in a Sino-Soviet competition of aid that enabled North Vietnam to launch the Tet Offensive in early 1968 in the first place. Rapprochement convinced the DRV to launch the Easter Offensive – a second Tet Offensive – in the spring of 1972. Détente eventually forced North Vietnam to rethink its strategy of trying to win a victory against the United States on the battlefield in Indochina and humiliate the superpower at the global level in the process. Despite Moscow and Beijing’s sustained loyalty throughout the conflict in the late 1960s and early 1970s, neither supported Hanoi’s overall strategy during the last years of the war. The Soviet Union preferred a negotiated solution to the conflict, while China jettisoned its world revolutionary positions in the 1970–72 period and instead counselled North Vietnam to settle for a negotiated agreement.

The period from the Tet Offensive in 1968 to communist victory in Vietnam, Laos, and Cambodia in 1975 revealed the close links between regional developments in the Indochina conflict and global changes in the Sino-Soviet–American relationship. Even while the United States and the Democratic Republic of Vietnam (DRVN, or North Vietnam) negotiated in Paris for almost five years from May 1968 to January 1973, they engaged in some of the most intensive and bitter military battles during the whole Indochina conflict. Simultaneously, the Sino-Soviet split came to full fruition during border clashes in 1969, followed by the parallel developments of Sino-American rapprochement and Soviet–American détente in the early 1970s. Although the Indochina conflict itself was firmly rooted in regional developments dating back to the interwar period, it occurred against the background of the Global Cold War. The American intervention after August 1964 amounted to the first full-scale attack by a capitalist power against a socialist state. Interestingly, it did not lead to greater fraternal cohesion among the socialist states but shattered the unity of the socialist world instead. In the second half of the 1960s, the Sino-Soviet–American relationship thus was characterized by trilateral hostility. While antagonism between the People’s Republic of China (PRC) and the Soviet Union, on the one side, and United States, on the other, had been a characteristic of the Global Cold War since the late 1940s, the Sino-Soviet fallout occurred at a moment when the DRVN needed to rely on fraternal unity. Even worse, as the Indochina conflict reached its apex with another round of escalations under the incoming administration of President Richard M. Nixon, the United States sought rapprochement with the PRC and détente with the Soviet Union. Even if the dual American policy of engaging with the two communist great powers had its roots in unrelated considerations, the Indochina conflict certainly was an additional motivation, but simultaneously also a complicating factor, for the United States.

Despite the enormous quantity of publications about the American involvement both in the Indochina conflict and the Global Cold War, our knowledge about Beijing’s and Moscow’s goals and policies on either level of analysis is remarkably scant. The continued lack of access to many archival holdings in Vietnam, China, and Russia forces historians to work with public sources, a relatively small amount of secondary literature published in any of the three countries, and sources from secondary archives throughout the world. This includes archives in countries of the former socialist world, neutral nations, and states that were involved in the war in various capacities, like Canada as a member of the International Commission for Control and Supervision (ICCS), Great Britain as an American ally that refused to participate in the war, and Australia as a US cobelligerent. The available puzzle-pieces thus produce a general, though not detailed, picture of the developments between 1968 and 1975 in the North Vietnamese–Sino-Soviet–American relationship. On the whole, they show Hanoi as a master of its own policies, Beijing and Moscow as loyal allies, even if they pursued policies of compromise with Washington, and rapprochement and détente as complicating factors for, but not obstacles to, the North Vietnamese goal of national unification.

The Tet Offensive

Following the US escalation in the wake of the Tonkin Incident in August 1964, Moscow and Beijing, given both their ideological disputes and increased Chinese security fears, vehemently disagreed on the appropriate policy of support of the DRVN. While the Sino-Soviet competition for North Vietnamese allegiance led to greater military and economic aid from both, it also caused bitter disputes among the three and led to Chinese policies of obstructionism of Soviet aid deliveries via the country’s railroad network.¹ As early as May 1965, Phạm Vӑn Đồng complained to the Soviet government about China’s unhelpful policies, and, by August, the North Vietnamese leaders started to move away from their previously pro-Chinese positions toward a political stance in the middle. In an internal report from mid-1966, North Vietnamese leaders bemoaned “the deep dissension between Russia and China … [that had] ruined the consistency of action of the pro-Vietnamese socialist bloc.” The Cultural Revolution further disturbed the Vietnamese communists, not only because of its radical political character and the internal chaos which it caused, but also because it politically and organizationally undermined the war effort against South Vietnam and the United States.²

The North Vietnamese leaders did not inform their Soviet and Chinese comrades about their plans for the Tet Offensive, although diplomats from the Soviet Union and socialist Eastern Europe noticed military preparations in the second half of 1967. Ahead of the offensive in late January 1968, the PRC rejected both negotiations with the United States on ideological grounds and an escalation of the war by the DRVN owing to security concerns. Still, Beijing endorsed Hanoi’s military initiative once the offensive had started but sharply criticized the North Vietnamese decision to accept the American offer of negotiations soon thereafter. Chinese leaders stressed that the only proper policy was to continue fighting for several years until the complete defeat of American imperialism on the battlefield. Moscow, too, had not expected a major military effort by Hanoi in late 1967; on the contrary, it believed that the DRVN was exhausted from three years of war. After the start of the Tet Offensive, the Soviet Union concluded that it was a last-ditch effort to change the balance on the battlefield ahead of negotiations with the United States, which, as Moscow believed, the Vietnamese communists had hoped would result from their military effort.³

After some months of fighting, Hanoi concluded that the Tet Offensive had not led to a decisive change on the battlefield, and thus embarked on a policy of negotiating while fighting. Against the background of the publicly stated need for a worldwide “united front” with “the socialist countries, the international workers’ movement, and the national liberation movement[s]” that would support the struggle in Indochina, the DRVN grew concerned about what it considered the “ideological confusion” in the socialist world that had emerged with the Prague Spring in Czechoslovakia in 1968. North Vietnamese leaders proposed as early as April fraternal help, with the goal of preventing “imperialist forces” from detaching that Eastern European country from the “ranks of the socialist countries.” Unsurprisingly, Hanoi welcomed the military intervention by the Soviet Union and the Warsaw Pact in Czechoslovakia in August 1968 as an act of preserving worldwide peace.⁴

Given its decision to negotiate with the United States in Paris, the DRVN pushed in the summer of 1968 for the withdrawal of the remaining Chinese troops, which had been stationed on the basis of a four-year-old agreement; the last Chinese soldiers left two years later. At the same time, the blockade and even plunder of Soviet military supply trains transiting the PRC by Red Guards, that is, radicalized young Chinese high school and university students, continued. Even if China’s supreme leader, Mao Zedong, had just called for a lessening of revolutionary fervor in the country’s foreign relations, because it had isolated the PRC on a global scale, the Soviet intervention in Czechoslovakia led to increased conflict between Beijing, on the one side, and Moscow and Hanoi, on the other. Of all occasions, China’s Prime Minister Zhou Enlai chose the twenty-third anniversary of the declaration of independence of the DRVN, September 2, to denounce Soviet “socialist imperialism” in Czechoslovakia, to accuse Moscow of imperialist collaboration with Washington on a worldwide scale, and to demand Hanoi continue fighting US imperialism on the battlefield and abrogate negotiations in Paris.⁵ Four weeks later, Zhou went even further by equating the recent Soviet intervention in Czechoslovakia with the four-year-old American intervention in Vietnam. North Vietnamese leaders subsequently complained to East German officials about Chinese accusations of ideological revisionism in the DRVN, although they simultaneously admitted that the PRC had not caused any problems in negotiating a new military aid agreement for the following year. Anyway, Hanoi was convinced that the worsening of the relationship with Beijing would be only temporary, and thus was willing to work for a relaxation of relations. By mid-November, against a background of increased Chinese fears of the Soviet threat following the events in Czechoslovakia, Mao eventually endorsed the North Vietnamese policy of fighting while negotiating with the United States in a conversation with Phạm Vӑn Đồng.⁶

Sino-Soviet Border Clashes and Cambodia

The latent Sino-Soviet border conflicts that turned into military clashes at Zhenbao/Damansky Island on the Ussuri River in March of 1969 troubled the North Vietnamese leaders greatly. As early as October 1968, Hanoi had raised its concerns about a possible military escalation between Beijing and Moscow over territorial disputes. Shortly after the clashes, Hồ Chí Minh offered to mediate between the PRC and the Soviet Union, largely because the DRVN feared that the conflict among the two communist giants would have a negative impact on its negotiating position in the ongoing Paris negotiations.⁷ Unsurprisingly, in his last will of May 10, 1969, Hồ expressed his grief “at the dissensions that are dividing the fraternal parties” and called for socialist unity instead. In concurrent talks with East German diplomats, North Vietnamese officials insisted on a middle position between the PRC and the Soviet Union, stressing that the military and economic aid they received from both was equivalent. During Hồ’s funeral in early September, the North Vietnamese leaders tried to bring Zhou and his Soviet counterpart, Aleksey Kosygin, together. After some bureaucratic slips, the two eventually met at Beijing airport on September 11, but their talks did not lead to any agreement. Chinese mistrust and continued veiled Soviet threats of a nuclear strike drove the PRC into a war scare by October. This eventually led to the clandestine Sino-American contacts in Warsaw at the turn of year that ultimately would end in rapprochement in 1971.⁸

But the embryonic Sino-American rapprochement suffered a setback following the coup against Cambodian Prince Sihanouk by his pro-Western prime minister, Lon Nol, on March 18, 1970, and the subsequent South Vietnamese and American military interventions in that country. Sihanouk himself ended up in exile in Beijing, where he swiftly formed an alliance with his erstwhile domestic enemies, the Khmer Rouge (the Communist Party of Kampuchea), and called for armed resistance to the new government. His Chinese hosts promised political support – largely to strengthen their position with regard to the Soviet Union and the DRVN – but hesitated to offer economic and military aid, while delaying the cut of all diplomatic relations with the new government in Phnom Penh for one and a half months.⁹ In comparison, North Vietnamese leaders considered the pro-American coup in Cambodia an outright military and political disaster, since it threatened to eliminate an important theater of military operations in the war against South Vietnam. The resulting hardening of Hanoi’s positions at the Paris negotiations taxed relations with Moscow, which had pushed for a diplomatic end to the war for years. North Vietnamese officials saw their policy toward Cambodia in terms of Soviet policy toward Czechoslovakia two years earlier – as a means to fight “counterrevolution” and American imperialism. In this context, DRVN leaders quickly supported Sihanouk’s plan to form a liberation army against Lon Nol’s government.¹⁰

On April 24 and 25, 1970, representatives of the DRVN, Laos, and Cambodia’s government in exile met in Nanning to form a united front designed to struggle against US imperialism in all of Indochina. Beijing was aware that Sihanouk sought rapprochement with the DRVN after years of difficult relations but simultaneously wanted to prevent North Vietnamese domination of all of Indochina. Even if the conference had been Sihanouk’s initiative, it was organized by the PRC and occurred in southern China.¹¹ In the wake of the trilateral conference, Mao publicly placed the anti-American struggle in Indochina into the context of an international anti-imperialist movement that eventually would overthrow “fascist rule in the United States” itself. On May 20, he ordered the suspension of any further steps toward Sino-American rapprochement. Later that month, Sihanouk traveled to Hanoi for talks with North Vietnamese and Laotian leaders on the details of collaboration. Excluded from the rapid developments in Southeast Asia, the Soviet Union downplayed China’s alliance with the “dead man” Sihanouk and tried to convince itself that Lon Nol needed the presence of the Soviet Embassy in Phnom Penh to prove his independence from the United States.¹²

Against the background of public, mutual Sino-American signaling about the resumption of rapprochement between July 1970 and March 1971, Sihanouk’s close relationship with the PRC deteriorated. Throughout this period, Western and socialist diplomats alike noted the reduction of ideological fervor and the rise of pragmatic tendencies in China’s foreign policy. Consequently, Sihanouk tried to establish a closer relationship with Hanoi’s leaders in early 1971, despite his continued disagreement with the DRVN over the presence of North Vietnamese troops in his home country.¹³

Sino-American Rapprochement

The first half of 1971 witnessed three major changes in the tangled web of Sino-North Vietnamese–American relations. The military failure of a combined American–South Vietnamese intervention in Laos in early 1971 reconfirmed the commitment of the Nixon administration to withdraw ground troops in the long term through complete “Vietnamization” of the war, while exploiting disagreements within the socialist world to negotiate an end to the conflict. In comparison, the unexpected military success of its own and allied troops in Laos persuaded Hanoi that the Saigon regime was an empty shell and Washington’s previous policy of Vietnamization had shortcomings. By May, it decided on launching a Tet Offensive-like military operation – the so-called Easter Offensive – during the US presidential election year of 1972, with the goal of damaging a sitting US president as the Tet Offensive had four years before. The DRV hence requested additional military assistance from the PRC and the Soviet Union.¹⁴ Simultaneously, the Sino-American signaling that had restarted in July 1970 led to informal contacts between the Chinese and US teams at the table tennis world championship in Japan in the spring of 1971. It continued with ping-pong diplomacy in April, Kissinger’s famous visit to the PRC on July 9–11, and the announcement of Nixon’s visit to Beijing, scheduled for February 1972, shortly thereafter.¹⁵

Although the Nixon administration had hoped to use rapprochement with the PRC to obtain Chinese leverage over the DRVN in the Paris negotiations, Zhou refused to abandon North Vietnam or to make any concessions on Indochina during Kissinger’s visit, even if such a rigid policy meant that the Taiwan issue would remain unresolved for many more years. Yet the very fact that the visit had happened put pressure on both the Soviet Union and the DRVN, as Nixon and Kissinger had hoped. Moscow hurriedly pushed for a summit with Washington, preferably even before Nixon’s visit to Beijing, but had to settle for one in May 1972. And Hanoi was enraged about what it considered Beijing’s sabotage of its war effort against Washington and political support for Nixon’s reelection bid in 1972. During a visit to the North Vietnamese capital on July 13, Zhou emphasized continued Chinese military and political support as well as his country’s principal commitment to unconditional American withdrawal from Indochina above all, but his hosts warned him of how Sino-American rapprochement would harden US positions in the Paris negotiations.¹⁶

Kissinger’s and Phạm Vӑn Đồng’s consecutive visits to Beijing in October and November, respectively, did not remove any of the disagreements. During Kissinger’s call, the United Nations (UN) General Assembly granted membership to the PRC and expelled the Republic of China on Taiwan – a direct consequence of his visit five months before. Even if Washington continued to expect diplomatic assistance from Beijing in the Paris negotiations with Hanoi, the PRC remained steadfast in refusing to lend any support. Disappointed, the Nixon administration accused the Soviet leadership of fomenting North Vietnamese intransigence and even threatened a deterioration of bilateral relations ahead of the Moscow Summit. Afraid of being excluded from developments in Indochina, Soviet leader Leonid Brezhnev in late January 1972 offered to help overcome the deadlock in the Paris negotiations.¹⁷

Zhou and Đồng similarly talked past each other in late November. Hanoi wanted Beijing’s unconditional commitment to a military solution in Indochina that would lead to the global humiliation of Washington, and thus demanded the cancellation of the Nixon visit. Disagreeing with what he considered an unrealistic maximalist strategy to seek victory only on the battlefield, Zhou in the talks with Đồng pushed for a negotiated end to the war and unconditional American withdrawal, while he publicly made commitments to North Vietnamese positions in the Paris negotiations. Throughout Đồng’s visit, the DRVN continued planning and preparing for its military offensive in the spring of 1972. Shortly after his return home from Beijing, Hanoi issued orders to the National Front for the Liberation of Southern Vietnam (NLF, or Viet Cong) to prepare for the spring offensive.¹⁸

Figure 8.1 Chinese Premier Zhou Enlai and President Richard Nixon toast each other (February 1972).

Source: Pictures from History / Contributor / Universal Images Group / Getty Images.

Nixon traveled to China on February 21 in a pessimistic mood about Vietnam. In 1967, even before he had become a presidential candidate, he had proposed to look beyond the Vietnam War to all of Asia, because China in good time would become a great power in its own right. But in the year before his visit to the PRC, he eyed China mainly as a potential lever to extract the United States from the Indochina conflict, and immediately before his departure from Washington he even questioned the value of his (now famous) visit, given Beijing’s firm commitment to Hanoi. During a week of talks, Nixon twice raised the Vietnam War, but Zhou Enlai remained firm on Chinese support for North Vietnamese demands on unconditional American withdrawal.¹⁹

Hanoi was deeply dissatisfied with Nixon’s visit, even if Beijing had promised beforehand not to give even an inch in the talks with the guest from Washington. North Vietnamese leaders were convinced that the visit would help Nixon to win the presidential election in 1972 even if he was unable to fulfill his four-year-old campaign promise to withdraw from Vietnam in his first term. Zhou traveled to Hanoi in early March to report on Nixon’s visit. While he again emphasized China’s support for North Vietnamese negotiating positions in Paris, he warned of illusions about another Tet Offensive–like campaign that he believed was unlikely to succeed. His hosts left him with no doubt about their belief that the Nixon visit had provided the United States with a morale boost that would make the Paris negotiations more difficult for the DRVN.²⁰

Easter Offensive, Détente, and Peace

In mid-March, Hanoi was overly optimistic about the impact on the Paris negotiations of the offensive, which was scheduled to start at the end of the month. In talks with East German diplomats two months later, North Vietnamese officials called unified Vietnam’s independence a “minimal goal” of the offensive but even hoped for a global defeat of US imperialism. Yet Soviet leaders reacted with irritation about the offensive, which occurred between Nixon’s visit to Beijing and his trip to Moscow in late May. In the face of Soviet charges of North Vietnamese attempts to undermine the Moscow Summit, the DRVN claimed that it had informed both the PRC and the Soviet Union in 1971 about its military plans, and had even requested – and received – military aid. It is likely that Beijing and Moscow knew about Hanoi’s plans, but probably were not aware either of the exact timing or of its Tet-style scale.²¹ Once the Easter Offensive had faltered by June, however, Hanoi did not hesitate to blame its communist allies for insufficient military support. Yet during the first weeks of armed operations, the PRC had stood firm on its military and political commitments to the DRVN, while Moscow denied any prior knowledge of Hanoi’s plans in communications with Washington. Still, the Soviet Union asked for a reduction in American retaliatory airstrikes in exchange for mediation between the DRVN and the United States.²²

Before Brezhnev received Nixon in Moscow in late May, he had to defeat a challenge by Soviet hard-line rivals who demanded a cancellation of the summit because of the recent escalation of fighting in Vietnam. In the first meeting with the American president, the Soviet leader clearly emphasized that détente and the bombing of North Vietnam were “incompatible.” After the signing of the sibling treaties on strategic arms limitation (SALT) and antimissile defense (ABM) – two major symbols of Soviet–American détente – on May 26, the two sides found common ground on Vietnam. Nixon was willing to make compromises on US positions on the Republic of Vietnam (RVN, or South Vietnam) in the Paris negotiations, while Brezhnev promised to send a delegation to Hanoi to mediate.²³ DRVN leaders were deeply frustrated that yet another of their socialist allies had hosted the American president, but they also realized that Vietnam was one of many problems the Soviet Union faced as a global power – and not even an important one at that.²⁴

By early June, it had dawned on Hanoi’s leaders that the Easter Offensive had failed to achieve a breakthrough. The casualty rate on the battlefield was immense, and the RVN was no closer to collapse. In many respects, the offensive had been a last-ditch effort to improve the military and diplomatic situation in Indochina and Paris, respectively. Even before its launch, North Vietnam’s population and economy had been exhausted after seven and a half years of war. On June 1, Hanoi ordered the mobilization of its last reserves in the vain hope of maintaining the offensive long enough to damage Nixon’s reelection chances. North Vietnamese leaders continued to blame the military failures on the lack of support by their communist allies – which in turn allowed them to demand more military aid – rather than on their own maximalist expectations and miscalculations.²⁵ Moscow, however, was irritated by Hanoi’s accusations, continued demands for military aid, and the general lack of a Marxist-Leninist analysis of the national and international situation.²⁶

By mid-1972, the DRVN had decided to resume negotiations in Paris. In early July, Zhou traveled to Hanoi to convince the North Vietnamese leaders to give up on their maximalist strategy of humiliating US imperialism globally through a military victory in Vietnam, and to settle instead on a fast American withdrawal and to delay national unification for some years into the future. Yet Hanoi believed until August that it could influence the presidential election and use this as a lever in negotiations in Paris. As it became evident by late August that the North Vietnamese people were completely exhausted by the continued war and that Nixon would win by a landslide, the DRVN changed track in order to get a final agreement in Paris before the presidential election in early November, so that Nixon could not escalate afterwards.²⁷ Yet by the same logic, the American president did not need such an agreement to win the election, and thus slowed down the negotiations in the hope to escalate it after his electoral victory to extract greater concessions from the DRVN. Both Beijing and Moscow were exasperated by Washington’s machinations, but their lack of diplomatic coordination deprived them of any leverage. The renewed US escalation of the war in December met with bitter North Vietnamese, Chinese, and Soviet criticism. Yet it was neither of the three communist countries but the decision of the American Congress to cut funding for the war that forced Nixon to negotiate a final agreement in Paris in late January 1973.²⁸

Indochina

In the two and a half years after the Paris Agreement on Vietnam, the situation in Indochina and the Global Cold War changed dramatically. By late March 1973, the last American troops had left Vietnam. Two years and one month later, the DRVN defeated and conquered the RVN, while the Khmer Rouge toppled Lon Nol’s government, and by August the communist Pathet Lao had taken control over all of Laos. Despite Brezhnev’s visit to the United States in June 1973, Soviet–American détente crumbled. After Nixon’s resignation in August 1974 in the wake of the Watergate scandal, his foreign policy was discredited to such a degree that his successor, Gerald Ford, even prohibited the use of the term “détente” in his administration. Simultaneously, Sino-American rapprochement stalled, to Mao’s great frustration, largely because Nixon had used it as a lever in achieving détente with the Soviet Union.²⁹ And despite the collapse of détente and rapprochement, Sino-Soviet relations did not improve. Yet at the Southeast Asian nexus of all these developments stood communist Vietnam’s attempt to dominate Indochina, which forced Beijing, Moscow, and Washington to readjust their respective policies toward the region.

Some Vietnamese communists had pursued hegemonic policies toward all of Indochina since the 1930s, though with long interruptions. As described above, Indochinese solidarity had returned to the political agenda following the coup against Sihanouk in March 1970. In view of Sino-American rapprochement and its own preparations for the Easter Offensive, the DRVN had returned by late 1971 to stressing Indochinese solidarity in the joint struggle against US imperialism. With Soviet political support, North Vietnam tried to increase its influence on the Cambodian government in exile, particularly the Khmer Rouge, at the expense of China.³⁰ In response, Beijing stressed its support for a united front in Indochina and the world for the struggle against US imperialism, despite the impending Nixon visit to the PRC. Regardless of Sihanouk’s continued, though rocky, relationship with the PRC, he traveled to Hanoi during Nixon’s visit to demonstrate North Vietnamese–Cambodian solidarity against the United States.³¹ The Sino–North Vietnamese tug-of-war for influence in Cambodia extended into the spring, with the DRVN making political commitments to the noncommunist Sihanouk (to the chagrin of the Soviet Union), and the PRC making public commitments to the struggle of all Indochinese people. According to foreign diplomats in Beijing, the Chinese leaders were not only convinced of the meager prospects of the Easter Offensive, but actually feared that its success would increase the influence of the DRVN in all of Indochina at the expense of the PRC. As the offensive faltered in the summer of 1972, the Sino–North Vietnamese competition for influence in Cambodia and Laos was suspended temporarily.³²

The struggle for influence in Indochina resumed after the Paris Agreement on Vietnam in early 1973. During a visit to the PRC in February, Kissinger discussed with Zhou and Mao steps to prevent Soviet hegemony in Asia and, by extension, the possible domination of Cambodia by pro-Soviet North Vietnam.³³ In turn, Moscow and Hanoi were concerned about alleged Sino-American agreements on Indochina as a whole and on Vietnam in particular. The Soviet Union was particularly anxious about the future development of Cambodia, because pro-Chinese and pro–North Vietnamese factions within the government in exile were fighting for dominance.³⁴ Yet, by comparison, Hanoi was optimistic about the revolutionary developments in both Laos, where internal conflict had ended with an agreement shortly after the Paris Agreement on Vietnam, and Cambodia, where it tried to increase its influence by reconciling the warring factions in the government in exile. But for much of 1973 and 1974 the struggle for dominance in Indochina remained undecided, as Soviet–American détente, Sino-American rapprochement, and Sino–North Vietnamese relations (due to unrelated territorial disagreements) faltered.³⁵

The North Vietnamese decision at the end of 1973 to use military means to achieve national unification had long-term consequences for the balance of influence in Indochina. The conquest of South Vietnam and the final Khmer Rouge campaign to overthrow Lon Nol’s government in Cambodia occurred roughly at the same time (January to April 1975), although they were not coordinated. Exploiting the deterioration of Sino–North Vietnamese relations, the Khmer Rouge managed to gain support from the PRC – at the expense of the DRVN and despite purges of Sihanouk’s pro-Chinese supporters in its ranks. Still Sihanouk celebrated the fifth anniversary of the North Vietnamese–Laotian–Cambodian meeting in Nanning in late April as a manifestation of fraternal solidarity.³⁶ Already in May of 1975, on the basis of the communist double success in Vietnam and Cambodia, North Vietnamese officials forecast more victories for socialism in Laos, Thailand, and the Philippines in the near future that would lead to the complete expulsion of US imperialism from all of Southeast Asia. Whether or not communist-led, unified Vietnam returned to ideas of an Indochinese confederation in 1975 is unclear. In any case, its attempt to establish relations with the new regime in Cambodia ended in failure.³⁷

The rapid changes in Indochina surprised the great powers, particularly the PRC. Afraid of losing all influence in Indochina, Beijing stepped up ideological propaganda against US imperialism in Asia and Soviet socialist imperialism worldwide in mid-spring. In talks with foreign diplomats, however, the PRC’s foreign minister, Qiao Guanhua, stressed the importance of US military bases in Asia to contain Soviet influence after Vietnamese reunification. Beijing feared not only an encirclement by the Moscow–Hanoi alliance, but also problems arising from the Vietnamese treatment of ethnic Chinese in recently occupied South Vietnam. This probably was why the PRC sent military aid and political advisors to Cambodia shortly after the overthrow of Lon Nol’s regime in order to freeze out Vietnamese and Soviet influence.³⁸ The Soviet Union, by comparison, placed the changes in Indochina into the larger context of a worldwide, victorious socialist advance against imperialism and capitalism. By the summer, Moscow was convinced that Hanoi had replaced Beijing’s influence in the new Indochina, but then was irritated that its longtime Vietnamese ally chose to stress its political independence from the fraternal socialist countries by becoming a member of the nonalignment movement by late summer.³⁹

By August, the Sino-Vietnamese struggle for Cambodia and Laos continued. During a visit to Phnom Penh early in the month, Lê Duẩn tried to improve the relationship, particularly with regard to territorial disputes that had emerged lately, but seemingly to no avail. A Cambodian state visit led by Khieu Samphan to the PRC in mid-August cemented the budding relationship with a technical agreement, mutual commitments for the struggle against Soviet and Vietnamese hegemonism, and an arrangement for Sihanouk to return to politics in Cambodia in some formal capacity.⁴⁰ Hanoi was happy about neither Beijing’s increased sway in what it considered its own sphere of influence nor the extreme domestic policies that the new regime in Phnom Penh imposed. At least, by August, the DRVN could celebrate the victory of its Laotian ally, the Pathet Lao, which had exploited the political insecurity in its country that had emerged after the rapid changes in Vietnam and Cambodia in the spring.⁴¹

The last months of 1975 revealed how much the relationship among all the players in Indochina had changed. During Lê Duẩn’s visit to Beijing in late September, the PRC announced that it would reduce its economic aid to the DRVN. Disagreements over the Soviet role in Asia convinced the Vietnamese leaders that the PRC had ceased being a socialist state. A month later, Lê Duẩn and the Soviet leaders cemented the bilateral relationship in Moscow, stressing the importance of the DRVN as an outpost of socialism and anti-imperialist revolution in Southeast Asia.⁴² In early December, the PRC hosted US President Gerald Ford. Mao started by complaining about the lack of progress in Sino-American rapprochement and Nixon’s instrumental use of the bilateral relationship to establish the now faltering Soviet–American détente. Still, the two countries agreed to coordinate their policies to forestall Soviet expansionism on both a global and regional scale. On December 7, on the thirty-fourth anniversary of the Japanese attack on Pearl Harbor, the president announced at a speech in Honolulu his “Pacific Doctrine,” which sought stability and peace in East and Southeast Asia on the basis of the American alliance with Japan and close bilateral collaboration with the PRC in economic and security matters.⁴³ The DRVN and Laos replied by denouncing the new doctrine as yet another attempt at American intervention in Indochina, warning of a Sino-Japanese–American alliance that represented only the interests of a few in the Pacific basin, and demanding a normalization of relations on the basis of the Paris Agreement.⁴⁴

The Sino-Soviet split, Sino-American rapprochement, and Soviet–American détente all influenced the North Vietnamese conduct of the war in the late 1960s and early 1970s, although not to the extent that DRVN leaders claimed at the time and in retrospect. The split made coordination of socialist aid in the second half of the 1960s difficult, but also resulted in Sino-Soviet competition for aid that enabled North Vietnam to launch the Tet Offensive in early 1968 in the first place. Rapprochement convinced the DRVN to launch the Easter Offensive – a second Tet Offensive – in the spring of 1972. Détente eventually forced North Vietnam to rethink its maximalist strategy of trying to win a victory against the United States on the battlefield in Indochina and humiliate the superpower at the global level in the process. Despite Moscow’s and Beijing’s sustained loyalty throughout the conflict in the late 1960s and early 1970s, neither shared Hanoi’s commitment to maximalist goals during the last years of the war. The Soviet Union had always preferred a negotiated solution to the conflict, while China jettisoned its world revolutionary positions in the 1970–2 period and instead counseled North Vietnam to settle for a negotiated agreement on American military withdrawal that would eventually open up the possibility for national reunification within a few years.

The realignment of Sino-North Vietnamese–Soviet relations in the 1968–73 period had a major long-term impact on the Cold War in East Asia. In the first half of the 1960s, the Sino-Soviet split had once more strengthened the Sino-Vietnamese communist concord of anti-imperialism and national liberation that dated back to the 1920s. The radicalism of the Cultural Revolution, which started in 1966, forced the DRVN to take up a middle position in between the PRC and the Soviet Union. Sino-American rapprochement in the early 1970s even augured closer Soviet–North Vietnamese collaboration. Sino-North Vietnamese competition for the allegiance of the Khmer Rouge after mid-1970 further accelerated the worsening of the mutual relationship. By the turn of 1978–9, the Soviet–Vietnamese alliance and Sino-American concord clashed during the Third Indochina War.