Foreign Relations of the United States, 1977–1980, Volume XXII, Southeast Asia and the Pacific

34. Intelligence Memorandum Prepared in the Central Intelligence Agency¹

RPM 78–10490

Washington, December 15, 1978

Another Cambodian War

Key Judgments

The pace of military activity in eastern Kampuchea is increasing and a major commitment of Vietnamese forces could occur at any time. Given Kampuchea’s military and political weaknesses, the constraints on Chinese ability to deter Vietnam and Hanoi’s overwhelming military advantages, the prognosis for the Pol Pot regime is not good. [portion marking not declassified]

Hanoi, with a much better informed reading of the situation in Kampuchea than our own, appears hopeful that its impending military campaign in eastern Kampuchea will lead to a quick unraveling of Phnom Penh’s military resistance, large-scale defections to its newly created Khmer National Front, and conditions of genuine civil war—in short, circumstances that would not require a highly visible, expensive and protracted Vietnamese military involvement in Kampuchea. [portion marking not declassified]

If the next several months do not produce such a scenario, we are not convinced that Hanoi necessarily will opt for an all-out military drive on Phnom Penh and the transparent imposition of a puppet government. Under such circumstances Hanoi could find itself involved in an indefinite occupation of Kampuchea in support of a puppet government encircled by anti-Vietnamese guerrillas possibly still supported by China through Thailand. Vietnam retains the option of a less exposed strategy—the gradual development of Khmer insurgent operations stiffened by limited Vietnamese military support and this could extend the conflict well beyond the dry season fighting period that ends in the late spring. [portion marking not declassified]

We doubt that Vietnam has committed itself to any absolute course of action or binding timetable at this point. If past performance is any guide, Hanoi will be ready to exploit to the hilt any opportunities. But, Hanoi also will be constantly reassessing Kampuchean military and political resiliency, the risk of Chinese counter-action, and the development of their Khmer insurgent organization in deciding how far and how fast to push its campaign. [portion marking not declassified]

The Chinese hope that a sudden collapse of the Pol Pot government can be averted, but they clearly are attempting to position themselves for a major setback in Phnom Penh. We believe that the Chinese recognize their extremely limited capacity to deter Vietnam and that they currently are concentrating on reactive options that will limit the damage to their prestige and credibility. [portion marking not declassified]

Peking’s fortunes in Kampuchea are not tied exclusively to Pol Pot. The Chinese apparently are considering supporting an anti-Vietnamese insurgency in Kampuchea whether or not Phnom Penh falls. Although we believe China is determined to avoid open conflict with Vietnam, it will take steps to demonstrate its determination to resist further Vietnamese expansion in the region. A propaganda offensive against Hanoi and its “hegemonistic” ally, the USSR, is already developing, but we may also see more tangible demonstrations such as stepped-up Chinese military presence on the Sino-Vietnamese border, or more aggressive patrolling in the South China Sea. [portion marking not declassified]

The manner in which deep-seated racial hatred, high emotion, and very real considerations of national interest and prestige intersect in the Kampuchean situation also argues for caution in attempting to precisely chart future developments. Heightened Sino-Vietnamese tension over Kampuchea could lead to miscalculation, outright conflict and larger consequences outside the realm of Southeast Asia that both sides would prefer to avoid. Our basic ignorance of internal political dynamics in Kampuchea and the resiliency of the Pol Pot regime also detracts from our confidence. We cannot rule out the possibility of sudden political change in Phnom Penh—the reemergence of Sihanouk or a descent into total anarchy and confusion—that could substantially alter our view and possibly cause a readjustment in Vietnamese strategy. [portion marking not declassified]

Hanoi’s Perspective

Unsuccessful in its efforts to attain a position of influence in Kampuchea through its involvement in the war against the former Lon Nol regime, Hanoi subsequently has even found it impossible to live alongside the successor Communist regime in Phnom Penh. Even before the war against Lon Nol ended, the Khmer Communist leadership was ruthlessly purging Vietnamese-trained and influenced Kampucheans and continued to develop ties with China, as Vietnam’s own relationship with Peking deteriorated. The Pol Pot regime has been both intransigent and provocative in pursuing the border dispute with Vietnam. The resulting conflict has cost many Vietnamese lives while draining away resources badly needed for Hanoi’s economic reconstruction efforts. [portion marking not declassified]

It has been clear for some time now that Hanoi last spring abandoned any hope of reaching a modus vivendi with the present regime in Phnom Penh. Large-scale Vietnamese military preparations, Vietnamese-sponsored Khmer resistance activity in eastern Kampuchea, and Hanoi’s new treaty with Moscow all point to this conclusion. Any lingering doubts on this score—if any existed—have been removed by Hanoi’s announcement on 3 December 1978 of a “Kampuchean National United Front for National Salvation.” By establishing and recognizing their own rival Khmer political alternative to the Phnom Penh regime, the Vietnamese, in effect, have inaugurated another Cambodian war. [portion marking not declassified]

Are the Vietnamese prepared to commit whatever level of overt military force may be necessary to install and maintain a friendly government in Phnom Penh? On paper the military solution, at first glance, seems simple; Vietnamese forces could easily be in Phnom Penh in a matter of days, if not hours. But in practice, the situation is not so simple. When political risks and larger strategic considerations are taken into account, the Vietnamese face a complex and potentially dangerous problem. Hanoi, well-experienced in the difficulties of maintaining military and insurgent operations in Cambodia, certainly understands the difficulty of imposing a “final solution.” We believe this recognition will greatly influence the decisions Vietnam will make as their campaign against Phnom Penh unfolds. [portion marking not declassified]

A United Offensive

Initial Vietnamese objectives will be largely limited to gaining the upper hand militarily in the region of Kampuchea east of the Mekong. In expanding and linking their existing enclaves, the Vietnamese will be attempting to preempt retaliatory Kampuchean strikes into Vietnamese territory and to secure and expand a base area for the development of a credible Khmer resistance force. We, as yet, do not have a clear idea as to existing insurgent capabilities. We do not have reports that some Khmer Communist troops have defected to the Vietnamese side. We doubt, however, that Hanoi’s Khmer forces will be able to operate as more than an auxiliary force during this dry season. The Vietnamese, of course, will be passing off the fighting in Kampuchea as the work of anti-regime insurgents; for the record, Hanoi denies that its own forces are in the country. [portion marking not declassified]

As in last year’s dry season campaign, Hanoi’s principal objective east of the Mekong will be the destruction of as much of the Kampuchean army as possible. Hanoi will be attempting to draw the Kampucheans into set-piece battles such as the one at Snuol in mid-November where the Vietnamese inflicted heavy losses on one of Phnom Penh’s divisions. The Vietnamese probably hope that a series of similar defeats will lead to a general collapse of Kampuchean resistance east of the Mekong and wholesale defection of Kampuchean units—developments that would indeed allow the struggle in Kampuchea to take on the characteristic of a genuine civil war and allow the Vietnamese to remain militarily in the background in subsequent fighting. [portion marking not declassified]

Or A Drive on Phnom Penh?

Hanoi, of course, cannot count on conclusive and optimum results from the initial round of dry season fighting, especially if the Kampucheans can continue to avoid the trap of set-piece battles and rely on the guerrilla tactics which have served them well in the past. Less conclusive results will confront Hanoi with a difficult choice: on the one hand, the swift imposition of a Vietnamese client regime in Phnom Penh—a course of action that will require a bald Vietnamese military drive against the capital and possible protracted fighting against Khmer Communist forces throughout the country—and, on the other, a more patient struggle based on limited Vietnamese military action and a long-term nurturing and expansion of allied Khmer insurgent forces—essentially the strategy adopted by Hanoi during the first Cambodian war against Lon Nol. [portion marking not declassified]

Hanoi clearly would prefer a quick end to the conflict in Kampuchea. High desertion rates from Vietnamese combat units and intelligence reports both indicate that service in Kampuchea is highly unpopular. More importantly, a protracted conflict could delay by years the planned economic reconstruction and integration of southern Vietnam. [portion marking not declassified]

Hanoi, however, will find no guarantee that the results of an all-out military drive on Phnom Penh will prove more conclusive or less expensive than a more patient and protracted strategy. Although the Pol Pot regime would not survive such a Vietnamese coup de main, there would be substantial resistance to a swift and blatant imposition of a Vietnamese puppet government in Phnom Penh. Hanoi’s Khmer force at this state would be in no position to provide the military underpinning for such an embattled regime. Under such circumstances Hanoi could find itself involved in an indefinite occupation of Kampuchea in support of a puppet government encircled by anti-Vietnamese guerrillas possibly still supported by China through Thailand. [portion marking not declassified]

The ASEAN states, Thailand in particular, see Vietnam’s moves against Kampuchea as evidence of Hanoi’s aggressive and ambitious nature—a reaction clearly anticipated and discounted in advance by Hanoi. But in reaching a decision to proceed with an all-out military option, the Vietnamese must still factor in the possibility of escalating political and diplomatic costs. Thailand, alarmed by the prospect of Vietnamese troops on its border, has contingency plans to back Khmer resistance activity against a pro-Vietnamese government and is probably prepared to cooperate with China in the process. The repercussions of Vietnam’s actions probably would ripple beyond Southeast Asia. Western aid would certainly decrease, chances of improving relations with the US set back, and Vietnam would be left even more dependent on the Soviet Union. [portion marking not declassified]

Hanoi must also factor the Chinese reaction into any decision to proceed with an all-out military effort, although they may now believe that [with] the treaty with Moscow, the chance of Chinese retaliation or intervention has been substantially reduced. In any event, we believe that the specter of a Kampuchean morass now is acting as a greater constraint on Vietnamese action against the Pol Pot regime than has the threat of Chinese counteraction. [portion marking not declassified]

The Chinese View

More, of course, is at stake than the continued existence of a Khmer government. China’s credibility in playing a great power role in Southeast Asia, and the future course of Sino-Vietnamese and, by extension, Sino-Soviet rivalry could be affected by the outcome of Kampuchea. For at least two decades the cultivation of an independent Cambodia, responsive to Chinese influence, has been a central feature of Peking’s policy in Southeast Asia. The imposition of a Vietnamese client regime there would be seen by the Chinese as a sharp Vietnamese and Soviet rebuff to Peking’s security and regional interests. [portion marking not declassified]

China’s geographic separation, its lack of adequate transport, and the xenophobic nature of its Khmer clients, however, sharply limit Peking’s ability to influence events on the ground. In the past Peking has seen little recourse but to depend on a weak and discouragingly eccentric regime to protect China’s interests in Kampuchea. [portion marking not declassified]

The Chinese still hope that the Pol Pot government can avoid a quick collapse and the resultant damage to Chinese prestige and interests. If the Pol Pot regime does not hold on during the course of this dry season, Peking’s policies in the region would remain essentially as they are today. The Chinese would continue sea and air supply to the Kampucheans, perhaps increasing it at whatever rate the regime could absorb. [portion marking not declassified]

Peking’s recognition that a major setback may now be at hand, however, is reflected by the increasingly pessimistic tone of private Chinese comments on the prospects in Kampuchea. The signing last month of a Soviet-Vietnam friendship treaty, while probably not significantly adding to the considerations that already had limited China’s options, almost certainly reinforced Peking’s judgment that the Vietnamese were prepared to pursue a confrontation with Phnom Penh that China could do little to deter. [portion marking not declassified]

Accordingly, Peking now is trying to make the point that Chinese credibility and long-term influence in Kampuchea and Southeast Asia in general are by no means tied exclusively to Pol Pot. China’s media reaction to events in Kampuchea has avoided enthusiastic support for Pol Pot or any direct threat to Hanoi. [portion marking not declassified]

Chinese officials, in fact, now are authoritatively ruling out the sending of combat troops to Kampuchea. The Chinese also have not attempted serious saber-rattling along the Sino-Vietnamese border or massive infusions of equipment into Kampuchea, probably because they recognize that these efforts would not constitute a serious constraint on Vietnam’s intentions. [portion marking not declassified]

China’s Options

These negative indicators, in addition to reflecting Peking’s pessimism about the prospects for Pol Pot, suggest that the Chinese now are concentrating on developing alternative reactions to a successful or partially successful Vietnamese campaign against Kampuchea, rather than on devising new, expanded means to save Pol Pot from military disaster. [portion marking not declassified]

If a viable, anti-Vietnam resistance develops after a collapse of the Pol Pot government, Peking clearly would attempt to stay in the game. Even if a substantial portion of Kampuchea falls to the Vietnamese, the Chinese could sustain supply lines to an insurgent force by air and sea (through Thailand if necessary), forcing the Vietnamese to divert resources to the Kampuchea fighting. Peking already has made some tentative arrangements with Bangkok for this contingency. [portion marking not declassified]

In short, Peking would seek to be in a position to assert that an independent Kampuchea still exists and that China was maximizing its efforts against Vietnamese “hegemonism.” Chinese would step up their charges of Vietnamese “interference” in Kampuchea and their warnings of Hanoi’s “expansionist” aims in the rest of Southeast Asia. Under these circumstances, the Chinese also could take satisfaction from their contribution to the Kampuchean morass into which Hanoi had fallen. [portion marking not declassified]

Depending on the pace and scale of Vietnam’s moves in Kampuchea, Peking may want to demonstrate its unhappiness to Hanoi. Peking could intensify its saber-rattling along the Sino-Vietnamese border by moving main force units to the region, stepping up air activity over the border, or provoking armed border incidents. Similarly, Peking could beef up its military presence on Hainan Island, on the Paracel Islands, and in the South China Sea generally. From these strengthened positions, the Chinese could attempt to harass Vietnamese shipping and naval activity, in or near the Tonkin Gulf. Peking could also strengthen its military presence in northern Laos or explore the possibility of supporting anti-Vietnamese forces there in a bid to harass the Vietnamese on a new front. [portion marking not declassified]

In pursuing this kind of activity, we believe China’s deep commitment to economic modernization at home, diplomatic outreach abroad, and concern about possible Soviet reactions will cause Peking to stop short of prompting outright conflict with Hanoi. On the other hand, we cannot rule out the possiblity that China, in seeking some psychological compensation for a defeat in Kampuchea, will pursue “punitive” operations against Vietnam that ultimately will have more far-reaching repercussions. There are always possibilities for miscalculation and over-reaction in a situation as emotion-laden as the current Sino-Vietnamese relationship. If the situation on China’s southern flank deteriorates to anything resembling war between the two countries, Peking would find it extremely difficult to withdraw without suffering even greater damage to its credibility than it would over the loss of Kampuchea. The USSR, under the terms of its friendship pact with Hanoi, might then be driven to attempt to divert Peking’s attention from Indochina, most likely by provoking some form of military confrontation on the Sino-Soviet border. [portion marking not declassified]

The Soviet Option

The Soviets for their part see the Kampuchean conflict as an opportunity to inflict a significant setback to Chinese interests in Southeast Asia at a relatively low cost and risk to themselves. Moscow probably believes that, as the situation evolves over the next few months, it will be required to do little more than continue providing political support and aid to the Vietnamese. Moscow, of course, cannot rule out the possibility that Hanoi’s move against Kampuchea could ultimately bring Sino-Vietnamese tensions to the point that some demonstration of further Soviet activity in support of its ally is required. [portion marking not declassified]

The Soviets could hold highly visible consultations with the Vietnamese under article six of their friendship treaty. The Soviets could step-up conspicuously the quantity and quality of their military aid to Vietnam. Moscow might also consider a naval portcall or show of force off the coast of Vietnam. Depending on events, the Soviets might ultimately consider engaging in some saber-rattling on the Sino-Soviet border, possibly in the form of increased reconnaissance or exercise activity. Moscow, however, has welcomed the relative quiet there since the fighting in 1969 and would be extremely loathe to raise the level of tension to the extent of provoking a renewal of cross-border incidents. [portion marking not declassified]

A Final Caveat

Our basic ignorance of internal political dynamics in Kampuchea and the stability of the Pol Pot regime further detracts from our confidence in estimating the future course of events. Hanoi may be underestimating the political and military resiliency of the Kampuchean regime. On the other hand, our limited information suggests both considerable political flux over the past three years and Chinese disenchantment with the Pol Pot regime. We cannot rule out the possibility of a new Chinese-backed “government of national union” coming to power in Phnom Penh, perhaps headed by Peking’s old ally Prince Sihanouk, which would announce sweeping domestic reforms and a new willingness to negotiate the border dispute with Vietnam. Peking might believe, perhaps more out of desperation than logic, that such a government could rally enough domestic and international support to cause Hanoi to scale back its objectives and military operations in Kampuchea. Another possibility, and perhaps a more likely one, is an internal political collapse in the face of Vietnam military pressure leading to total confusion and anarchy throughout the country—a situation that probably would impel Vietnam to fill the political vacuum swiftly with its own Khmer government. [portion marking not declassified]

1. Source: Central Intelligence Agency, Office of Support Services (DI), Job 80T00634A: Production Case Files, Box 5, [unfoldered material]. Secret; [handling restriction not declassified]. A note on the first page indicates the memorandum was prepared by the East Asia-Pacific Division of the Office of Regional and Political Analysis and was coordinated with the Office of Strategic Research in the National Foreign Assessment Center.