CHINA AND AMERICAN CONDUCT OF THE VIETNAM WAR
C. Dale Walton
Department of Defense and Strategic Studies
Southwest Missouri State University
CHINA AND AMERICAN CONDUCT OF THE VIETNAM WAR 
The ominous precedent of the Korean War guided the Vietnam decisionmaking process: the fear of military intervention by the People's Republic of China was a major ingredient shaping American policy in the conflict. Worries about possible intervention by China impacted many aspects of American warmaking in Vietnam, and fear of the communist giant played an important part in all decisions on escalation. In their effort to avoid provoking the PRC, US policymakers conducted the war in Vietnam in a fashion so unsound militarily that the American effort in that country was fundamentally undermined. Concerns about the provocation of China affected American bombing strategy, policy relating to Laos and Cambodia, and, especially, the debate over direct military action against North Vietnam.
The caution exercised by American decisionmakers was, however, self-defeating. As is demonstrated below, the leadership of the PRC wished to avoid war with the United States and would probably have only intervened in Vietnam in a case of perceived self-defence. Even very energetic action against North Vietnam might not have brought China into the war, although there certainly would have been a substantial possibility of this outcome. Furthermore, and of primary importance, Chinese intervention most likely would not have prevented a positive outcome of the Vietnam situation for the United States. 
Given the constraints placed on the US government by public opinion, the limitations on the conduct of the war had the effect of severely undermining the Vietnam undertaking. American policymakers could not fight a counterinsurgency campaign with nebulous goals in South Vietnam and perpetually maintain public support, yet they felt compelled to do so because they were unwilling to accept the hazards incidental to escalation of the conflict. Thus, the PRC, merely by maintaining its reputation as a bellicose power and credible protector of the DRV, was able to impair grievously the American effort in Vietnam and prevent policymakers from even considering options that might have secured a military victory over the Indochinese communists.
For policymakers in the Kennedy and Johnson Administrations, the Korean War was a recent event that ‘was still fresh in nearly every mind in Washington'.  In 1950, China convincingly had confirmed its willingness to intervene on behalf of a neighbouring communist power when the latter's survival was in doubt.  Indeed, China's bold intervention in Korea occurred despite numerous problems and disadvantages for the PRC. For instance, the communists had only recently seized control of the mainland and ended a decades-long period of warfare; there was an enormous disparity between the war potential of the American and Chinese economies and the general quality of their respective military forces; the United States possessed nuclear weapons and China did not; and, even though the PRC and the Soviet Union were functional allies neither power fully trusted the other.  The PRC even accepted the risk that the United States would use nuclear weapons against Chinese soil and/or accept no outcome to the conflict short of unconditional victory; the Chinese had no way of assuring that the United States would not escalate the conflict and, although it quickly became clear that President Truman wished strictly to limit Sino-American hostilities, Mao had taken a mighty risk by attacking American forces.
It is unsurprising that the perceived recklessness of China impressed Kennedy and Johnson Administration policymakers. There were obvious parallels between the situations in Korea and Vietnam and the American concern about Chinese intervention was justifiable—it would have been irresponsible for decisionmakers not to consider the possibility that China would intervene on North Vietnam's behalf. Indeed, while many American policymakers overestimated the degree of direct Chinese control over the DRV,  their belief that Chinese leaders would view an invasion of North Vietnam as a possible threat to China itself was essentially correct.
Yet, despite the importance of Indochina to the PRC, domestic and international circumstances would likely have served to constrain Chinese responses to American actions against North Vietnam. In the 1960s China wished to avoid a war with the United States,  and American policymakers erred too far on the side of caution in their effort to avoid a military confrontation with the PRC. The perceived need to ‘avoid another Korea' blinded key decisionmakers, most notably President Johnson and Secretary McNamara, to two key details. First, the geographical, political-diplomatic, military, and other circumstances of the Vietnam conflict were substantially different from those which resulted in the Chinese intervention in Korea. Overall, these differing circumstances had the effect of discouraging Chinese intervention in Vietnam. Second, even if China had intervened in Vietnam with the maximum force which it could immediately bring to bear, it is unlikely that it would have been decisive on the outcome of the war.
From the Yalu to the Mekong
On 27 November 1950, Chinese troops (supposedly ‘volunteers') launched a surprise offensive against US/UN forces; having moved stealthily southward from Manchuria, the PLA scored early victories against the American Eighth Army and threw most US Army units in the northern DPRK into flight. Compared to US forces the PLA was grossly under-equipped and under-mechanised, but it successfully took advantage of the American belief that a massive assault was unlikely at that time (even though a small Chinese expedition into North Korea, probably intended as a warning, had already occurred in October-early November) and successfully ‘divided [UN commander Gen. Douglas] MacArthur's overextended forces, and precipitated the greatest American military retreat in history'.  For a brief time, the PLA was able to use ‘surprise, night fighting, and speed to overcome a professionally-training, well-equipped, and technologically superior enemy'. 
Even at the height of Chinese fortune in the war, however, Maj. Gen. Oliver P. Smith's First Marine Division, along with some US Army and ROK units, conducted an extraordinary fighting withdrawal from the Chosin Reservoir and inflicted severe casualties on the PLA despite an overwhelming Chinese advantage in numbers.  Shortly thereafter, under the guidance of Lt. Gen. Matthew Ridgeway, the reorganised Eighth Army was shaped into a highly effective fighting force. Ridgeway ‘turned [the] Eighth Army into a huge killing machine' that he called ‘the Meat Grinder'.  The grisly nickname was appropriate. The PRC suffered enormous causalities—great numbers of Chinese died in the war (including Mao Anying, one of Mao Zedong's sons)  —but was nonetheless unable to eject the Americans from the Korean peninsula. This reversal of fortune was accomplished despite Washington's unwillingness to place the US economy on a full wartime footing, commit a mammoth field army to Korea, attack targets in mainland China, or use nuclear weapons. The United States fought a highly constrained war but achieved its key goal, the preservation of South Korean independence, and did so notwithstanding the fact that as the war continued (unnecessarily, since the PRC refused until July 1953 to settle for peace terms that it could have obtained much earlier) it became very unpopular in the United States.
The Chinese leadership had little reason to see the American presence in Vietnam as being a threat comparable to that presented by the United States in Korea. The Korean peninsula was a convenient base for large-scale operations against China (including the capital and key industrial centres in Manchuria), and Mao clearly believed that a unified Korea containing US troops posed a danger to the Chinese communist regime.  In fact, Mao probably even believed that an American invasion of China was imminent;  in February 1972, Zhou Enlai informed Alexander Haig that the PRC had not merely attempted to prevent an American victory in Korea. For understandable reasons, Mao feared for the survival of his government:
[Zhou Enlai] told [Haig] that the Chinese had entered the war because they believed, in the wake of MacArthur's shattering victory, that they were confronted by a pincers movement in which the American armies would advance on Beijing from Korea while Chiang Kai-shek's reequipped and retrained Nationalist forces would invade the mainland across the Strait of Formosa under the protection of the U.S. Seventh Fleet and strike for the capital . . . Geographically and militarily, an operation of this kind was by no means impossible: Beijing is only four hundred air miles from the North Korean frontier, less than the distance from Pusan to the Yalu River. The United States certainly possessed the power to carry out a successful attack from Korea; Chiang had half a million troops, recently rearmed and retrained by the Americans, on Formosa; and, as a result of the very first order issued by President Truman after the North Korean invasion of the South, the Seventh Fleet was on station in the Formosa Strait. To the Communist regime in Beijing, which had been in power for less than nine months, these factors may very well have added up to something that looked like a mortal threat. 
Chinese concern about the American position in Korea were not irrational: the United States was hostile to the CCP and, as Haig observes, the situation in Korea clearly offered the United States and ROC an opportunity to return control of the mainland to Chiang Kai-shek. Mao had no way of reliably knowing that Truman believed ground war with China to be totally unacceptable; the PRC's analysis of the situation was, although obviously flawed, logical if not entirely reasonable.  In retrospect, it is quite unsurprising that the circumstances of late 1950 agitated Mao, who was extremely suspicious of the United States and confident of his personal military prowess (a volatile combination of attitudes).  Also, a formal alliance between the PRC and the USSR had been signed shortly before. This secured China's northern flank and provided a basis for hope that, if complete Chinese failure in the war was imminent, the Soviet Union might intervene on behalf of its ally.
The American involvement in Vietnam presented China with very different problems than did the war in Korea and there were few sensible reasons for Mao to believe that Vietnam would be the base for an American invasion of China. By the 1960s, the communist government was well-established on the Chinese mainland; long-term military-political factors had shifted in the PRC's favour and it was deeply improbable that Chiang Kai-shek's dream of reconquering the mainland would ever be realised;  the ‘road to Beijing' was secure and a revived and heavily armed DPRK stood between American forces on the Korean peninsula and the PRC; despite tensions during and after Korea, the United States had never attempted to overthrow the CCP regime by force; and, the Sino-Soviet relationship had degenerated to the point that some Chinese leaders undoubtedly saw the USSR, rather than the United States, as posing the greatest threat to the territorial integrity of the PRC. Moreover, Indochina was not a desirable region from which to launch an invasion of the PRC, even if the United States were so inclined: there was no critical military-political ‘centre of gravity' to attack in the part of China directly north of Vietnam.  The capital city, industrial core areas, most military bases, and virtually everything else valued by the Chinese regime were located far from the Sino-Vietnamese border. This was the opposite of the case during the Korean War, where Mao's army was underarmed and China's capital and industrial core were vulnerable to a pincers formed by the American and Nationalist Chinese armies. 
PRC worries about American aggression were deeply misguided,  but such fears nevertheless appear to have been genuine;  Chinese actions during this period provide persuasive evidence that the Chinese leadership feared an attack by United States. Certainly, efforts such as the Third Front development programme, which ‘was premised on the assumption that in the event of war with the United States, China's established industrial center along the coasts would be destroyed or occupied in the early stages of the conflict', indicated that China feared attack by the United States.  In 1964, as China still struggled to overcome the effects of the Great Leap Forward, Mao initiated the costly ‘Third Front' development programme, which was intended to increase industrial production in the interior of the PRC. The Third Front diverted scarce government development funds away from urban coastal regions to (commonly rugged) rural areas. This vastly increased the cost of development projects and, because resources were distributed inefficiently and often used unwisely, the overall process of industrialisation in China was slowed.  Although not a terrible catastrophe like the Great Leap Forward—it did succeed in rapidly increasing the level of heavy industry in the Chinese hinterlands—the Third Front was exceedingly expensive (nevertheless, the programme continued until 1971, a measure of the regime's devotion to its goals). Even though it was nominally an industrial development programme, the Third Front's primary benefits were largely intended to be military: by industrialising the interior, the PRC would be prepared for a long war of resistance that would oblige a would-be aggressor to fight a difficult war in China's vast spaces. Along with other evidence, the Third Front strongly indicated a primarily defensive mentality on the part of Mao and indicated that Chinese worries about military vulnerability were quite strong.
It is difficult to provide a wholly satisfying explanation for Chinese concerns in the 1960s, but much of the answer is probably to be found in the political culture of the PRC. The antipathy of the United States was assumed, and Chinese policymakers (wrongly, but not irrationally) believed that Washington would act to destroy the PRC if it were given the opportunity.  The Chinese error was to misunderstand fundamentally the attitudes of the Kennedy and Johnson Administrations and the general political culture of the United States. PRC policymakers simply did not believe that an unprovoked major offensive against China was impossible, even though that was in fact the case. 
All Chinese leaders did not, however, share the same vision of how best to cope with the perceived threat from the United States. Many Chinese policymakers no doubt were willing to conduct an extremely high-risk strategy of confrontation with the United States and, despite the obvious risks, some probably wanted to commit PLA ground units to battle. Such an attitude, however, did not guide the actions of Mao and his immediate circle. Indeed, Mao—who, despite challenges to his authority, remained the pre-eminent Chinese decisionmaker throughout the 1960s—was apparently inclined to avoid unnecessary confrontation with the United States. Nevertheless, given Mao's backing of the effort to create a ‘Third Front' within China and other evidence, it appears that he believed Nationalist China, the United States, and the Soviet Union presented clear long-term threats.  He did, however, feel sufficiently confident in China's short-term safety to concentrate on domestic issues and launch the Cultural Revolution.
In retrospect, it is probable that Mao was attempting to strike a difficult course: avoiding the appearance of weakness in the face of the United States, which would create internal political problems (and, he probably assumed, encourage American aggression), simultaneously avoiding unduly provocative actions that would bring about a war, and making prudent preparations for a possible conflict with the United States. Judging from China's half-hearted actions in this period, the PRC's general preference was to avoid war with the United States, but its attitude toward the Vietnam situation was still in flux when the Cultural Revolution descended on China.
A Tormented Giant
The United States enjoyed more and greater military advantages over China in Vietnam in the mid-1960s than it did in Korea in the early 1950s.  Although the Chinese army of the 1960s was somewhat better equipped than the very light Chinese infantry units that were common in Korea, the PLA was damaged acutely by the Great Leap Forward, and hunger and disaffection among its troops were major problems in the early-to-mid 1960s.  Also, unlike the experienced combat troops that struck the Americans early in the Korean War, the PLA of the period was mainly composed of conscripts who had never seen combat. Furthermore, the good order and disciple of the PLA—already weakened by the Great Leap Forward—was deeply damaged by a series of Maoist political initiatives. ‘Professionalism' and hierarchical discipline were attacked, guerrilla doctrine enjoyed a resurgence in influence, and the need to apply Maoist principles to the PLA was emphasised. As a result, the PLA of the mid-1960s was a profoundly troubled institution.
With the purge of [Peng Dehuai] in 1959, Lin [Biao] became minister of defense and moved the PLA sharply in the Maoist ideological, nonprofessional direction. In June 1965, the abolition of ranks within the PLA was the final step in its ‘democratization' and thus deprofessionalization, precisely when United States military involvement in Vietnam significantly intensified. This entire process was accompanied by the gradual dismissal of almost all the highest officers who ever had directed the PLA in its purely military capacity. 
Because of the victory over India in the 1962 Indo-Chinese border war, Marshal Lin ‘could claim that the bringing of politics into the Army had in no way affected its ability to wage war, but had actually increased its morale and fighting spirit'.  This was a dangerous delusion: India was a weak opponent and the Indo-Chinese conflict was very brief and constrained;  the 1962 clash offered few useful lessons for a war against either the United States or the Soviet Union.
The ‘professionals' (anti-Maoists) within the PLA were concerned by the politicisation of the military, and these worries increased as the American involvement in Vietnam deepened and China made contingency plans for intervention in the war.  Their concerns were well justified: the PLA was grossly ill-prepared for a high-tempo modern war against a first-class power, and sizeable, direct Chinese intervention in the Vietnam War would have been costly in human terms and logistically near-impossible.  American troops, well-trained and thoroughly supplied with excellent equipment, were formidable. Furthermore, in Vietnam the PRC would suffer from major disadvantages that it had not experienced in the Korean War. Most notably, in the 1960s the PRC was growing increasingly concerned about the Soviet Union. Sino-Soviet relations were fairly amicable in the early years after Mao's victory over the Nationalists, but progressively soured; by 1964, the level of Sino-Soviet trust was very low and Chinese leaders could not be confident that their northern border was secure (and were no doubt concerned that the United States and Soviet Union might even co-operate militarily against China). Third, North Vietnam's ports could be easily closed by the United States and the Chinese land logistic network into Vietnam was inadequate to the task of supporting large expeditionary forces and vulnerable to American airpower.
Finally, and perhaps most importantly, China was undergoing a long-term domestic political and economic crisis. The disastrous Great Leap Forward, initiated in the late 1950s, had grievously damaged the economy, and resulted in enormous declines in industrial and agricultural production.  Mao's ill-conceived (and sometimes bizarre) policies created one of the worst famines in human history: approximately thirty to sixty million Chinese died,  and PRC agricultural and industrial progress was set back by years or even decades. The Soviet Union's decision to discontinue aid and assistance programmes to China in summer 1960 further damaged Chinese industry,  and did conspicuous damage to the PLA.
Rather than granting the PRC an opportunity to recuperate from the economic troubles of the late 1950s to mid-1960s and stabilise politically, Mao initiated the Great Proletarian Cultural Revolution. The Cultural Revolution and its aftershocks threw Chinese society and government into acute crisis from 1966 until the end of the decade.  The instability in China was reflected in the politically divided PLA and viciously self-destructive Chinese leadership: Red Guard factions battled each other and the PLA, the political leadership suffered instability and denunciation, and the Chinese Communist Party was shattered.
It is probable that the Cultural Revolution so weakened the Chinese government that it was unfeasible for the PRC to undertake any substantial military action in Vietnam from late 1966 onward. The Cultural Revolution was a period of virtual civil war; at a time when riots and military engagements were occurring in China itself the actions of the Americans in Vietnam must have seemed comparatively unimportant to most Chinese decisionmakers. Indeed, the majority of CPP leaders undoubtedly expended most of their energy on the problems of preserving their own careers and avoiding ‘reeducation' or worse at the hands of fanatical youths.  Severe domestic crisis tends to act as a constraint on foreign policymaking (internal troubles certainly affected the policymaking process in Washington, even though domestic problems in the United States were minuscule compared to those in the PRC). China was a state on the verge of starvation in the early 1960s and of implosion in the latter 1960s, and these crises impaired the PRC's ability to craft an effective foreign policy and, particularly, to enforce that policy through force of arms. 
The Years of Greatest Danger
In the middle 1960s, the American military commitment to Vietnam increased exponentially; meanwhile, China was undergoing a breathing period between the Great Leap Forward and the Cultural Revolution. The period of relative domestic calm in China between 1962 and 1965 would have been the most convenient time for the PRC to intervene in Vietnam, and was also a time when the fear of the United States was high in PRC policymaking circles  (it is also notable that on 16 October 1964 the PRC detonated its first atomic device, an event that may have bolstered China's confidence while at the same time confirming the Johnson Administration view that China was a powerful foe).
Throughout the 1960s, the Chinese government hinted that it would intervene militarily in Vietnam if the United States invaded the DRV.  After American air attacks on the DRV, Premier Chou Enlai warned the United States that the PRC might not idly stand by while the United States committed ‘aggression' and Foreign Minister Chen Yi indicated that China would fight if the United States invaded North Vietnam.  China also, however, tended to qualify some of its more aggressive rhetoric with vague indications that a Sino-American war would only occur if the United States attacked China or gave that country good reason to believe that an attack on its territory was imminent.  Chinese leaders avoided explicitly stating that an attack on only the southern portion of the DRV would not result in PRC military action, as this would indirectly have given the United States license to invade China's client, but Chinese statements about the PRC's commitment to North Vietnam tended to be somewhat tepid and reflected China's own concern about encirclement and a possible American invasion of the PRC.  Even strong Chinese statements tended to avoid specific commitments, instead keeping the level of Chinese tolerance deliberately vague while nonetheless implying that the PRC might take action in Vietnam.
In addition to public statements, the PRC did take many concrete actions to assist the DRV militarily. Most importantly, China supplied North Vietnam with military hardware, even at the cost of denying the PLA needed equipment.  The DRV would have been unable to carry on the fight in South Vietnam effectively without the multitude of rifles, artillery shells, bullets, other supplies supplied by the PRC over the course of the war.  Until Sino-Vietnamese relations deteriorated substantially in the later 1960s, China also performed construction work and anti-aircraft defence for North Vietnam.
Official Chinese estimates indicate that 1,707 American aircraft were shot down and 1,608 others damaged by the PLA,  but these numbers are exaggerated—they substantially surpass the American figure for the total number of US aircraft shot down (1,096) during the war. Nonetheless, the Chinese commitment to North Vietnam's air defence was impressive, and reportedly ‘[f]rom August 1965 to March 1969, a total of 63 divisions (63 regiments) of Chinese anti-aircraft artillery units, with a total strength of over 150,000, engaged in operations in Vietnam'.  The PRC was responsible for air defence for its own construction troops, as well as defence of certain strategic targets, such as railroads, in the northern portion of the DRV.
Chinese construction troops assisted Hanoi mainly by constructing and repairing rail lines, roads, bridges, telephone lines, and defence works. Most construction activity in Vietnam occurred from 1965 to 1968 (although some went on until 1970); work generally took place north of Hanoi, and apparently never below the 20th parallel.  These projects were nevertheless sizeable, and the PLA built well over a thousand kilometres of roads, as well as hundreds of bridges, in North Vietnam.
The total Chinese contribution to the North Vietnamese war effort was, in manpower terms alone, substantial: PRC figures indicate that from 1965-69, about 320,000 troops served in Vietnam, with 170,000 there at the peak of the Chinese commitment.  By performing air defence and mundane construction tasks, the PRC enabled the North Vietnamese to send troops into other parts of Indochina that otherwise would have been tied down at home. Perhaps even more importantly, the Chinese commitment gave the DRV confidence that it had a reliable great power protector. The North Vietnamese leadership was thus energised to continue with their national unification project in the difficult years of the later 1960s, when war costs were high, victory uncertain, and US-RVN progress in counterinsurgency was considerable. China convincingly promised to protect the one thing that the North Vietnamese leadership truly valued: the survival of their regime. So long as the PRC acted as guarantor of the national survival of North Vietnam and (along with the USSR) provided the means to carry out the war, the DRV was willing to pay the human costs of the conflict.
China was, however, uneasy with its role as protector of the DRV, despite the fact that Washington policymakers, who did not want to inflame Sino-American tensions, rarely mentioned Chinese involvement in the Vietnam War (and very much avoided publicly dwelling on the fact that the PLA was responsible for the capture or death of a large number of American pilots). There was ‘a growing feeling of isolation and [siege] in Beijing, just as the United States began to increase substantially its involvement in Vietnam, posing the possibility of a direct attack on southern China in the near future'.  In April 1965, ‘the CCP Central Committee issued ‘Instructions for Strengthening the Preparations for Future Wars', a set of directives which would ultimately be relayed to every part of Chinese society and become one of the most important guiding documents in China's political and social life for the rest of the 1960s'.  The Instructions noted that American aircraft were entering the airspace of the DRV, stated that the PRC needed to improve its readiness for a war with the United States and made it clear that support for the DRV was considered a vital part of China's foreign policy.
In June 1965, North Vietnamese leader Van Tien Dung visited Beijing (Ho Chi Minh had visited China a short time before, in May-June) and the Chinese privately undertook potentially very serious obligations. PRC leaders agreed that if the United States used its sea and airpower to support a South Vietnamese invasion of the DRV, then would respond with its own naval and air forces. Further, if American land forces actually invaded North Vietnam, then ‘Chinese troops were to serve as Hanoi's strategic reserve, ready to assist in defense or to launch a counterattack to take back the strategic initiative'. 
In addition to making promises, the PRC took limited steps to prepare for a military confrontation with the United States. Notably, the PLA constructed a large base complex at Yen Bai in the Northeast part of the DRV. The complex ‘grew to nearly two hundred buildings and a large runway with attendant facilities' and, in the event that Hanoi and Haiphong were overrun offered the North Vietnamese, provided ‘a viable refuge on home territory for continued resistance, in contrast with the plight of the North Korean regime after fleeing Pyongyang'.  Moreover, if the PRC decided to enter the war in force, the complex could also have served as a base camp for Chinese troops. In addition to Yen Bai and additional projects in North Vietnam, the PRC also undertook other measures, such as building new airfields immediately north of the DRV and undertaking ‘a systemic reinforcement of its air power, both by increasing the number of aircraft and by concentrating its relatively few MIG-19s which had previously rotated between Northeast and East China', as well as conducting joint air exercises with North Vietnamese fighters. 
Overall, the substantial Chinese contribution to the DRV war effort and the willingness of the PRC to promise the North Vietnamese that it would act as guarantor of their sovereignty provides impressive evidence that, at least in the mid-1960s, China would have been willing to contemplate entry into the Vietnam War.  This evidence is, however, not sufficiently compelling to indicate that China would certainly have fought on behalf of North Vietnam. It is conceivable that China would have been willing to renege on its promises to Hanoi if it believed that the United States posed no threat to China. Importantly, the PRC might have made a distinction between actions merely harmful to North Vietnam and those endangering Chinese territory. For example, an American invasion with the clear (stated or unstated) intention of eliminating the DRV as an entity, like the United States/United Nations invasion of North Korea, probably would have goaded Beijing into attempting action at almost any time in the war. On the other hand, even in 1965 an invasion a few miles north of the DMZ with very limited and clearly stated goals might not have overly excited the Chinese leadership.
In any case, the middle part of the 1960s was for China clearly the period of greatest capacity and will to defend North Vietnam. The PRC's likely reactions to American actions in Vietnam varied over time and both the Chinese desire and capability to become involved in Indochina degraded rapidly from 1966 onward. For example, if in 1965 the United States had undertaken an invasion of the DRV and announced a limited but ambitious goal for its effort—such as occupation of the Red River Delta, including Hanoi and Haiphong but leaving the northernmost portion of the DRV in communist hands—the PRC would likely have attempted to fight in Vietnam. If, however, this had occurred in 1967, China's capability to intervene would have been degraded and Mao might have been inclined to seek a quick settlement of the war. 
The year 1965 was, in retrospect, pivotal to the Sino-American relationship. The United States decided to fight the Vietnam War mostly in South Vietnam and to utilise an operational style that did not fundamentally alter for the rest of the war; the Chinese, in turn, chose to tolerate an American war in Indochina waged on those terms and did not modify their policy for the remainder of the war. American decisionmakers chose to place avoidance of a war with China above all other considerations (except of course the complementary goal of averting war with the USSR, which was correctly believed to be far less likely), even victory in Indochina. This consideration remained primary for the remainder of the war, although this was less important to Nixon than to Johnson. Developments within China and the United States progressively made the principal forces constraining the American war effort domestic rather than international and it was prudent for policymakers to assume that actions such as the mining of Haiphong or the Linebacker bombing campaigns would not bring about a conflict with the PRC.
An Unready Foe
There are abundant reasons to doubt that even in the mid-1960s the PRC was capable of successfully initiating and sustaining a major expeditionary war against the United States in Indochina. A March 1964 memorandum for the Secretary of Defense from the Joint Chiefs of Staff states that:
An assessment of enemy reactions to [possible American military action against North Vietnam] indicates that the Chinese communists view Laos and South Vietnam as DRV problems. It is unlikely that the CHICOMs would introduce organized ground units in significant numbers into the DRV, Laos, or Cambodia except as part of an over-all campaign against all of Southeast Asia. They might offer the DRV fighter aircraft, AAA units, and volunteers. They would assume an increased readiness posture and CHICOM aircraft might be committed to the defense of North Vietnam. The Soviets would probably be highly concerned over possible expansion of the conflict. To the extent that Moscow believed the Hanoi and [Beijing] regimes in jeopardy, Sino-Soviet differences would tend to submerge. It is believed that Moscow would initiate no action which, in the Soviet judgment, would increase the likelihood of nuclear war. 
Thus, in the best judgement of the Joint Chiefs of Staff—who were, of course, the principal uniformed military advisors to the president—action against North Vietnam presented some risk of escalation, but minimal risk of catastrophic escalation (a major war with China or, even worse, a conventional or nuclear war with the Soviet Union).  The JCS allowed for the possibility that China might take military action against several countries—including South Korea, Taiwan, and several Southeast Asian states—but noted that ‘logistic limitations severely restrict that ability to sustain a major land, sea, and air campaign in more than one area'. 
The JCS calculated that, as of the time of the memorandum, ‘[thirteen] CHICOM infantry divisions, less heavy artillery and armour, plus nine DRV divisions could be logistically supported during the dry season (November-May) in initial moves against Southeast Asian countries'. In addition, it was estimated that the PRC ‘could make available about 400 jet fighter and 125 jet light bombers for operations in Southeast Asia', and could also conduct minor naval operations, possibly including the use of a small number of submarines. However, it was also noted that during the rainy season there would be a great decrease in the potential size of Chinese offensive operations.
The JCS estimate of potential Chinese combat power indicates that, far from being overwhelming, the military force that China could immediately bring to bear in Indochina was modest.  Thirteen relatively light Chinese divisions could not possibly have delivered a crushing blow against US forces in Vietnam: such a force would lack the mass, firepower, mobility, and troop quality to defeat American forces quickly. In addition, the approximately five hundred aircraft that the JCS estimated the PLA might use would have been insufficient in number and too low in quality to effectively threaten American air superiority.
The PLA depended on mass and surprise temporarily to rout the Americans in Korea; in Vietnam, it would not have enjoyed either advantage over the United States to a significant degree. Repetition of the early Chinese victories in the Korean War would have been extremely unlikely in Vietnam, as this would have required American policymakers to ignore all the lessons of the Korean experience, invading North Vietnam while leaving no buffer zone in the northern portion of that country, ignoring Chinese troop movements, and making other extraordinarily gross errors of judgement.
In the event of an American invasion, the defence of the North Vietnamese territory would have been very challenging for the PLA, and it would have been difficult for communist forces to retain control of strategically vital areas of North Vietnam. Command of the air and the sea would (probably quickly) have been secured by the United States. Even if the PRC had made a full effort to contest control of the sky, the quality of both PAVN and PLA aircraft and pilots were too low to allow communist forces seriously to contest American land- and carrier-based airpower for very long (the great majority of the aircraft losses that the United States suffered over the course of the war were the result of an anti-aircraft network constructed over the course of several years, during which time American policymakers often refused to destroy SAM sites that were under construction in North Vietnam).
Ability to command the air, in turn, was a vital component of the overall American advantage in firepower. Various combinations of modern artillery, tactical and strategic aircraft, naval gunnery, and armour gave the United States the capability to deliver an enormous quantity of accurate fire on strategic and tactical targets. Both the PRC and PLA lacked the technical-industrial capability to match American firepower, a disadvantage that would severely hampered any communist attempt to launch a counteroffensive and regain the initiative.
The fact that the PRC and DRV share a common border would have been logistically convenient for the two communist goverments, but would not have guaranteed that Chinese assets could be easily moved into Vietnam. Given the terrain, logistical issues, and the likely ease with which the United States could have attained command of the air, and hence been able to target traffic on major roads in the DRV, Chinese units would have generally operated at a marching pace. Given the high level of mechanisation of the United States military, and the American tradition of logistical excellence, this would have meant a substantial advantage in road movement for American forces. Furthermore, the helicopter gave American forces the ability to move large numbers of fighting men with extraordinary speed and flexibility (a vitally important capability the US Army had not possessed in Korea, where helicopters were primarily used for reconnaissance and transportation of casualties). Helicopters made isolated enemy units vulnerable, provided the United States with the capability to harass enemy logistics, and enabled American forces facing enemy pressure to receive support quickly.
In order to defend North Vietnamese territory effectively, Chinese commanders would have been obliged to mass their forces and fight US forces in pitched battles in which their units would have been exposed to American artillery and air power.  Guerrilla tactics that communist forces employed with success in the war in South Vietnam would be irrelevant to defensive operations. Communist forces could, of course, have been pulled back into a rump DRV (assuming such an entity existed) or into China itself and thereafter conducted raids and other small operations (perhaps while preparing for a large offensive intended to eject allied forces from the DRV). That, however, would have ceded control of the great majority of North Vietnam's population and industrial capacity to the RVN.
The aforementioned facts should have served to reassure President Johnson and Secretary McNamara that they could, with considerable confidence, escalate the war against North Vietnam, but it appears to have had little impact on them. President Johnson privately professed great concern about China. At one point he even stated that, ‘If one little general in shirtsleeves can take Saigon, think about two hundred million Chinese coming down those trails. No sir! I don't want to fight them'.  Leaving aside the obvious exaggeration in Johnson's statement, it summarises Washington's attitude toward the PRC. Many American leaders were in awe of China's population, had respect for China's potential power, and found the idea of confronting such an enormous country deeply disconcerting. Nevertheless, Johnson and McNamara refused to acknowledge that, giant though China was, it cast only a small military shadow over Indochina.
In retrospect, it is astonishing how easily China deterred the United States from undertaking many potentially effective military actions in Vietnam. This is all the more surprising given the cautious nature of China's deterrence threats; Beijing's relatively subtle warnings were not particularly bellicose and were not characteristic of a state eager for war.
In classical deterrence theory, both the credibility and severity of a deterrence threat are important factors in judging its likely effectiveness,  but when the evidence is examined in an objective fashion, China's threats were both dubious (its willingness to actually go to war on Hanoi's behalf was very doubtful, except perhaps in the event that the United States were clearly attempting to destroy the DRV) and rather weak (for the reasons noted above, it is unlikely that China could have presented the United States with an overwhelming military threat in Indochina). Therefore, Beijing should, in theory, have enjoyed little success in its efforts to coerce Washington; feeble deterrence threats are often challenged, and the United States had much to gain if it successfully ‘called China's bluff'. Nonetheless, Chinese leaders were highly successful in their deterrence efforts; during the Johnson years the United States constrained its behavior in very significant ways, such as refusing to bomb the rail links between China and the DRV or to mine Haiphong Harbor. 
It would appear that several factors worked together to create a particularly agreeable environment for Chinese deterrence efforts. First, China's intervention in the Korean War and its willingness to accept casualties in that conflict had a substantial impact on American views of Chinese deterrence credibility. In the 1960s American policymakers were inclined to treat Chinese threats as being highly credible. Second, American leaders were reluctant to ‘test' China, a country that was perceived to be a radical and unpredictable revolutionary power. Johnson Administration policymakers were not confident that they understood the boundaries of China's tolerance or that the latter was willing yield as readily as the Soviet Union might in a similar situation. The American tendency to be cautious of China's government was related to Beijing's intervention in Korea, although it was not exclusively the result of that event. Third, Lyndon Johnson and numerous other US policymakers greatly feared war with China. They were psychologically inclined to exaggerate China's military power and to discount information that cast doubt on its capabilities. Fourth, key American leaders were unsure of how they wished to conduct the Vietnam War and Chinese attempts to prevent vigorous US military actions actually simplified their decisionmaking process and made it easy for them to reject options that they would have been reluctant to undertake in any case. In this sense, American leaders ‘wanted' to be deterred.
China's most important interest related to the American effort in Vietnam were concerns about the territorial integrity of the PRC itself. The DRV was mainly (and merely) a buffer state and unreliable client regime and although Chinese leaders publicly stated that Hanoi was the legitimate government of all of Vietnam, making this claim a reality was certainly not central to China's overall national interests. The primary reason for China to offer protection to the DRV was to assure that the conflict in Vietnam did not result in an American invasion of the PRC. North Vietnam was not itself valuable enough to warrant a major war with the United States, and even though China was seeking to expand its influence in Indochina, its key short-term concerns were defensive.
All other considerations were secondary to China's territorial integrity, and this created a perceived dilemma for Chinese policymakers that was, ironically, not unlike that experienced by American leaders. The PRC believed that it had to deter the United States from offensive action against China, but did not know precisely the limits of American tolerance—insufficient responses to supposed provocations could conceivably cause the United States to believe that China was weak and thus encourage aggression, while overly energetic action might cause American policymakers to overreact violently and invade China.
American decisionmakers worried that China would intervene in Vietnam while Chinese leaders were concerned about the possibility that the United States would invade China. Both sides were fundamentally misguided: it was unlikely that China would intervene in Vietnam in a fashion that would change the ultimate outcome of the war or vastly increase American casualties, and the United States had no desire whatsoever to fight the PRC (least of all on the home territory of the latter). The United States was deeply disadvantaged by its misconceptions. The belief that the PRC was on the verge of war deterred American decisionmakers from invading North Vietnam, the action that offered the best chance of allowing a speedy and favourable settlement of the Vietnam situation, or even undertaking several lesser options. For example, the fear of China played a major role in the Kennedy Administration decision to seek the neutralisation of Laos and the Johnson Administration's tendency to pursue a ‘slow squeeze' bombing strategy rather than an intense bombing offensive.  The erroneous estimation of China's military power and willingness to enter the war contributed mightily to the American loss in Vietnam. If American policymakers had made a less cautious estimate of Chinese intentions and military capabilities, the intellectual environment in Washington would have been very different.
The PRC, on the other hand, successfully deterred the United States from invading North Vietnam or undertaking other strong military actions, even though that was only a secondary goal for China. The perceived need to stand up to the United States resulted in Chinese actions that demonstrated to American leaders like Johnson and McNamara what they were predisposed to believe, that the PRC was a power willing to go to war with the United States and that any American military action in North Vietnam would automatically result in a ‘Korea II', a large-scale war in Indochina in which hundreds of thousands of PLA troops would overwhelm American forces.
China's deterrence of the United States would not have been possible if American decisionmakers had not been highly risk-averse. The PRC was an available bogeyman that reassured Johnson, McNamara, and other American policymakers who were reluctant to take robust action in Vietnam that their course was the only prudent one. Civilian policymakers consistently chose to ignore the advice of the Joint Chiefs of Staff and others who argued that China's ability to project military power effectively into Vietnam was minimal. American leaders generally preferred to be highly cautious and assume that the PRC possessed enormous military capabilities and the will to fight a costly war in Indochina. They had overlearned from the experience in Korea, and did not give sufficient weight to the PRC's many known military-political problems or realistically consider the problems that the PLA would have in projecting power into Indochina.
 Substantial portions of this paper are drawn from C. Dale Walton, The Myth of Inevitable Defeat in Vietnam (London and Portland, OR: Frank Cass, 2002), Chapter 5.
 A March 1966 poll indicated that American citizens were dedicated to the Vietnam enterprise even if China intervened in the war. Respondents were asked: ‘If Red China decides to send a great many troops, should we continue to fight in Vietnam, or should we withdraw our troops?' Only 8% wished to withdraw under those circumstances, 19% had no opinion, and 73% favoured continuing the war. Survey cited in John E. Mueller, War, Presidents, and Public Opinion (New York: John Wiley & Sons, 1973), p. 86.
 Alexander M. Haig, Jr., with Charles McCarry, Inner Circles: How America Changed the World: A Memoir (New York: Warner, 1992), p. 133. It also should be noted that Korea had a formative influence on American thinking about limited war and ‘flexible response'.
 In an interview, Col. Harry G. Summers (USA, ret.) argued persuasively that Chinese intervention was a ‘great shock' to Dean Rusk and that this affected his Vietnam decisionmaking, inclining him toward caution on the question of whether to invade North Vietnam. Interview with author, 9 September 1997, Bowie, MD.
 For a study of Sino-Soviet relations in the Korean War era see Sergei N. Goncharov, John W. Lewis, and Xue Litai, Uncertain Partners: Stalin, Mao, and the Korean War (Stanford, CA: Stanford University Press, 1993).
 However, China certainly had influence over Hanoi's warmaking decisions. See Xiaoming Zhang, ‘The Vietnam War, 1964-1969: A Chinese Perspective', The Journal of Military History, 60, 4 (October 1996), pp. 736-39.
 See Robert Garson, ‘Lyndon B. Johnson and the China Enigma', Journal of Contemporary History, 31, 1 (January 1997), p. 79.
 David Allan Mayers, Cracking the Monolith: U.S. Policy Against the Sino-Soviet Alliance (Baton Rouge, LA: Louisiana State University Press, 1986), p. 92.
 Rosemary Foot, The Practice of Power: US Relations with China Since 1949 (Oxford: Clarendon Press, 1995), p. 145.
 See Eliot A. Cohen and John Gooch, Military Misfortunes: The Anatomy of Failure in War (New York: The Free Press, 1990), pp. 186-90.
 Geoffrey Perret, A Country Made By War: From the Revolution to Vietnam—the Story of America's Rise to Power (New York: Random House, 1989), p. 464.
 Stanley Karnow, Vietnam: A History (New York: Penguin Books, 1984), p. 329.
 See Li Zhisui, trans. Tai Hung-chao, The Private Life of Chairman Mao (New York: Random House, 1994), p. 117.
 See Richard H. Bernstein and Ross H. Munro, The Coming Conflict with China (New York: Alfred A. Knopf, 1997), p. 78.
 Haig, Inner Circles, pp. 48-9.
 For a study that emphasizes factors in Beijing's Korean War decisionmaking other than China's fear of invasion, particularly its goals as a revolutionary power, see Chen Jian, China's Road to the Korean War: The Making of the Sino-American Confrontation, The U.S. and Pacific Asia: Studies in Social, Economic, and Political Interaction (New York: Columbia University Press, 1994).
 Mao may have been virtually alone among the CPC leadership in favouring intervention in Korea, but his authority at the time was so great that he nevertheless prevailed over more timid decisionmakers. John W. Garver, ‘Little Chance', Diplomatic History, 21, 1(Winter 1997), p. 88; Goncharov, Lewis, and Xue, Uncertain Partners, pp. 176-83; and Chen, China's Road to the Korean War, pp. 218-9.
 Nevertheless, in April 1964, Chiang speculated to Secretary of State Rusk about a possible ROC invasion of the mainland. ‘Summary Record of the 528th Meeting of the National Security Council, Washington, April 22, 1964, 4:45 p.m'. FRUS, 1964-1968, p. 1:258.
 The greatest Chinese worry in the early 1960s was of a US-ROC threat to the coast of the PRC. In a 1962 speech wherein the term ‘Third Front' was first publicly used, Lin Biao warned that Nationalist forces ‘might take advantage of the post-Great Leap Forward crisis to launch an attack on mainland cities, and suggested that such an attack could not be successfully resisted in the coastal cities, especially if Kuomintang forces were backed by American naval power'. Barry Naughton, ‘The Third Front: Defence Industrialization in the Chinese Interior', The China Quarterly, no. 115 (June 1988), p. 352.
 In contrast to the area north of the DRV, South Manchuria was ‘China's principal industrial base, [consuming] one-third of its power supply; Shenyang's 2,000 plants accounted for the bulk of its machine-building capability; Anshan and Benxi produced 80 percent of its steel; and Fushan was the site of its largest coal mine. All these industrial centers were less than 200 kilometers from the Yalu. Furthermore, the Suiho Hydroelectric Station, the largest of its kind in Asia, and other smaller stations were on the south bank of the river'. Goncharov, Lewis, and Xue, Uncertain Partners, pp. 183-4.
 Not only Beijing was concerned about the possibility of an American campaign against China. Hans J. Morgenthau warned that war with China was possible and, indeed, that the logic of the American position in Vietnam might lead the United States to initiate it. ‘The extension of war into North Vietnam can be interpreted as an attempt to create in Hanoi the psychological precondition for a negotiated settlement. But it can also be interpreted as an attempt to change the fortunes of war in South Vietnam by rupturing the assumed causal nexus between the policies of Hanoi and the victories of the Viet Cong. This causal nexus is a delusion, which has been given the very flimsy appearance of fact through the White Paper of 28 February. A policy derived from such a delusion is bound to fail. Yet when it has failed and when failure approaches catastrophe, it would be consistent in terms of that delusionary logic to extend the war still farther. Today, we are holding Hanoi responsible for the Viet Cong; tomorrow we might hold Peking responsible for Hanoi'. ‘War with China?', Survival, 7, 4 (July 1965), pp. 155-59. It should be noted that Morgenthau's belief that the NLF was not controlled by the DRV, which is central to his logic, is false. See R.B. Smith, An International History of the Vietnam War, vol. II, The Struggle for South-East Asia (London: Macmillan, 1985), p. 37.
 A 1966 CIA estimate indicated that Mao and those close to him believed that if there were a substantial number of troops on the Chinese border, the United States would choose to join the ROC in an effort to overthrow the communists. See Bevin Alexander, The Stranger Connection: US Intervention in China, 1944-1972, Contributions to the Study of World History, no. 34 (New York: Greenwood Press, 1992), pp. 198-99.
 John W. Garver, ‘The Chinese Threat in the Vietnam War', Parameters, 22, 1 (Spring 1992), p. 79.
 See Naughton, ‘The Third Front', pp. 375-81.
 There was also great disagreement in Western political and academic circles during the 1960s about the PRC's military capabilities and intentions. See for example, Henry Brandon, ‘The Dilemma of S.E. Asia', Survival, 7, 1 (January-February 1965), pp. 38-40; Donald S. Zagoria, ‘Communism in Asia', Commentary, 39, 2 (February 1965), pp. 53-8; George Lichtheim, ‘Vietnam and China', Commentary, 39, 5 (May 1965), pp. 56-9; Benjamin Schwartz, ‘Chinese Visions and American Policies', Commentary, 41, 4 (April 1966), pp. 53-59; Kenneth T. Young, ‘American Dealings with Peking', Foreign Affairs, 45, 1 (October 1966), pp. 77-87; Roderick MacFarquhar, ‘Mao's Last Revolution', Foreign Affairs, 45, 1 (October 1966), pp. 112-24; Lucian W. Pye, ‘China in Context', Foreign Affairs, 45, 2 (January 1967), pp. 229-45; Stefan T. Possony, ‘Mao's Strategic Initiative of 1965 and the U.S. Response', Orbis, 11, 1 (Spring 1967), pp. 149-81; Alexander Woodside, ‘Peking and Hanoi: Anatomy of a Revolutionary Partnership', International Journal 24, 1 (Winter 1968/9), pp. 65-85; Bernard Fall, et al., ‘Containing China: A Round-Table Discussion', Commentary, 41, 5 (July 1969), pp. 413-23.
 It is possible Mao believed in the late 1950s that the United States feared war with China but that his personal outlook concerning China's strategic environment darkened in the early 1960s and he came to consider a joint Soviet-American attack on China to be conceivable. See He Di, ‘The Most Respected Enemy: Mao Zedong's Perception of the United States, China Quarterly, no. 137 (March 1994), pp. 152-4.
 Interestingly, however, in 1969 Mao supposedly presented his personal physician with a geopolitical riddle: ‘Think about this . . . [w]e have the Soviet Union to the north and the west, India to the south, and Japan to the east. If all our enemies were to unite, attacking us from the north, south, east, and west, what do you think we should do?' The next day the physician was unable to answer, and Mao explained that, ‘Beyond Japan is the United States. Didn't our ancestors counsel negotiating with faraway countries while fighting with those that are near?' Li, The Private Life of Chairman Mao, p. 514.
 While the PRC tested its first nuclear weapon in 1964, it is extremely unlikely that Beijing would have judged nuclear usage in Vietnam to be to its advantage. Chinese use of nuclear weapons would have invited American retaliation in Vietnam (if not against China itself)—and the United States possessed a vastly larger and more advanced nuclear arsenal.
 Karnow, Mao and China: From Revolution to Revolution (New York: Viking, 1972), pp. 108-9.
 C.W. Cassinelli, Total Revolution: A Comparative Study of Germany Under Hitler, the Soviet Union Under Stalin, and China Under Mao (Santa Barbara, CA: Clio, 1976), p. 216.
 Gerald H. Corr, The Chinese Red Army: Campaigns and Politics Since 1949 (New York: Schocken, 1974), p. 149.
 For an analysis of the Sino-Indian clash see Allen S. Whiting, The Chinese-Calculus of Deterrence: India and Indochina (Ann Arbor, MI: The University of Michigan Press, 1975), pp. 1-169.
 Corr, The Chinese Red Army, p. 149.
 For an analysis of the logistic difficulties facing the PRC, see Herman Kahn, ‘On Establishing a Context for Debate', in Frank E. Armbruster, et al., Can We Win in Vietnam?: The American Dilemma, Hudson Institute Series on National Security and International Order, no. 2 (London: Pall Mall, 1968), pp. 56-7.
 It is indicative of the poor quality of American intelligence on China during this period that a July 1959 National Intelligence Estimate stated that China's ‘economy is rapidly expanding' and calculated ‘that Communist China will be able to increase its GNP by about 12 to 15 percent in 1959'. ‘National Intelligence Estimate', 28 July 1959, Foreign Relations of the United States, 1958-60 (Washington, DC: GPO), pp. 19:577-8. In reality, the Chinese economy was on the verge of total collapse in 1959.
 Arthur Waldron, ‘“Eat People”'—A Chinese Reckoning', Commentary, 104, 1 (July 1997), p. 29. As Waldron recounts, the famine was so severe that it resulted in widespread cannibalism in the Chinese countryside.
 Karnow, Mao and China, p. 103.
 On the turmoil within China see Simon Leys, trans. Carol Appleyard and Patrick Goode, The Emperor's New Clothes: Mao and the Cultural Revolution (London: Allison & Busby, 1977).
 In 1967, radical violence was so prevalent in the provinces that ‘a number of provincial and municipal officials were brought to Beijing so that their physical safety could be ensured'. Harry Harding, ‘The Chinese State in Crisis, 1966-9', in Roderick MacFarquhar (ed.), The Politics of China: The Eras of Mao and Deng, 2nd ed. (Cambridge: Cambridge University Press, 1997), p. 211.
 It can be argued that Mao's decision to launch the Cultural Revolution should not necessarily be taken as evidence that he believed that war with the United States was unlikely in the short term. ‘Just as Stalin believed that elimination of internal opposition dovetailed with the forced industrialization of the Five Year Plans to prepare the Soviet Union for war, Mao may well have believed that the purge of revisionists from China's leadership prepared China for battle. Mao, like Stalin, may have been mistaken about the military efficacy of his purges. That, however, is another matter'. John W. Garner, ‘The Chinese Threat in the Vietnam War', Parameters, 22, 1 (Spring 1992), p. 82. Nonetheless, it seems very unlikely that Mao would have undertaken the Cultural Revolution if he believed that war with the United States was imminent; just as Stalin undertook his purges as part of a long-term strategy, Mao probably believed that the Cultural Revolution would unsettle China in the short term but strengthen it in the long term.
 This was also apparently a period (particularly in 1965) when powerful factions in China evidently wished to take an active part in the Vietnam ground war. See Karnow, Mao and China, pp. 147-53.
 See Foster Rhea Dulles, American Foreign Policy Toward Communist China, 1949-1969 (New York: Thomas Y. Crowell, 1972), pp. 214-5.
 Ibid., p. 215.
 Kissinger notes that Defence Minister Lin Biao's September 1965 article ‘Long Live the Victory of People's War!' was interpreted as a warning by the Johnson Administration not to invade North Vietnam, but they ignored ‘Lin's subtext, which stressed the need for self-reliance among revolutionaries. Reinforced by Mao's comment that Chinese armies did not go abroad, it was meant as well to provide a strong hint that China did not intend to become involved again in communist wars of liberation'. Diplomacy (New York: Simon and Schuster, 1999), p. 645.
 See Whiting, The Chinese Calculus of Deterrence, pp. 189-94.
 Zhang, ‘A Chinese Perspective', p. 737.
 This generous supply continued despite the progressive widening of the Sino-Vietnamese breach, and even after Richard Nixon's visit to China. See Chen Jian, ‘China's Involvement in the Vietnam War, 1964-68', China Quarterly, no. 141 (June 1995), p. 379.
 Zhang, ‘A Chinese Perspective', p. 759.
 Chen, ‘China's Involvement', p. 376.
 Ibid., p. 375.
 Zhang, ‘A Chinese Perspective', p. 759
 Kenneth Leiberthal, ‘The Great Leap Forward and the Split in the Yan'an Leadership, 1958-65', in MacFarquhar, The Politics of China, p. 129.
 Chen, ‘China's Involvement', 367.
 Zhang, ‘A Chinese Perspective', p. 750. Also see Qiang Zhai, China and the Vietnam Wars, 1950-1975 (Chapel Hill, NC: University of North Carolina Press, 2000), p. 131.
 Whiting, The Chinese Calculus of Deterrence, p. 188.
 Ibid., pp. 176-77.
 See Zhai, China and the Vietnam Wars, pp. 155-56.
 On the US military's assessment of the probability of Chinese intervention, Adm. Elmo Zumwalt, Jr. (USN, ret.) stated in an interview that: ‘The military view was that . . . the Chinese would not come in, because we had in essence defeated them in Korea. We stopped their invasion, and slowly moved them back, and got the truce. . . [S]ince then we had by a double order of magnitude improved our armed forces equipment and technology, whereas the Chinese had not, so the Chinese would know that we were better by far than we were in Korea, and we were better then they were in Korea. Second, if we were wrong, and they came, we could whip them . . . [T]he military view always was that we could seize Haiphong and Hanoi, not go out any further north, and put the war out at the heart, instead of dealing with the fingertips in the jungles of South Vietnam. Interview with author, 4 September 1998, Rosslyn, VA.
 ‘Memorandum for the Secretary of Defense', 2 March 1964, Papers of Robert S. McNamara, RG 200, Box 82, United States National Archives, NN3-2000-092-001 HM 92-93.
 It is now clear that the most US policymakers were correct in their presumption that the Soviet Union genuinely wished to avoid a violent confrontation with the United States over Vietnam. See Ilya V. Gaiduk, The Soviet Union and the Vietnam War (Chicago: Ivan R. Dee, 1996), passim.
 ‘Memorandum for the Secretary of Defense', 2 March 1964, Papers of Robert S. McNamara.
 Other estimates of Chinese combat power, conducted both before and after 1964, tended to be sceptical of the PRC's overall capabilities. See Foot, The Practice of Power, pp. 150-166.
 It should be borne in mind that the climate and prevalent terrain in Vietnam is as alien to most Chinese as it is most Americans. There was no more reason for a soldier from Beijing to feel at home in the Vietnamese hinterlands than there was for a soldier from New York City to feel at home in a Florida swamp. Jungle fighting was not a particular speciality of the People's Liberation Army and disease and discomfort would likely have hampered the fighting efficiency of Chinese forces.
 Karnow, Mao and China, p. 406.
 For a general discussion of deterrence see Keith B. Payne and C. Dale Walton, “Deterrence in the Post-Cold War World,” in Strategy in the Contemporary World: An Introduction to Strategic Studies (New York: Oxford University Press, 2002), pp. 161-82.
 The military significance of the latter decision and Nixon's eventual reversal of this policy is discussed in Walton, Myth of Inevitable US Defeat, pp. 114-20. Also see Ibid., Vietnam: Avoidable Tragedy or Prudent Endeavor? Review essay, Comparative Strategy 19, 4 (October-December 2000), pp. 358-59.
 See Foot, The Practice of Power, pp. 158-9.