100. Memorandum From Secretary of Defense McNamara to President Johnson1
SUBJECT
- Evaluation of the Program of Bombing North Vietnam
Summarized below, as you requested, is an evaluation of the program of bombing North Vietnam.
1. Rationale for bombing the North. The program of bombing NVN began in an atmosphere of reprisal. We had had the August Tonkin Gulf episode; we had absorbed the November 1 attack on Bien Hoa Airfield and the Christmas Eve bombing of the Brinks Hotel in Saigon. The attacks at U.S. installations at Pleiku on February 7 and Qui Nhon on February 10 were the immediate causes of the first strikes against North Vietnam. The strike following Pleiku was announced as a “response”—a “reprisal”; our strike following Qui Nhon was called a response to more generalized VC terrorism. The major purposes of the bombing program, however, were:
- a.
- To promote a settlement. The program was designed (1) to influence the DRV to negotiate (explicitly or otherwise), and (2) to provide us with a bargaining counter within negotiations.
- b.
- To interdict infiltration. The program was calculated to reduce the flow of men and supplies from the North to the South—at least, to put a ceiling on the size of war that the enemy could wage in the South.
Supplemental purposes of the program were (c) to demonstrate to South Vietnam, North Vietnam and the world the U.S. commitment to see this thing through, (d) to raise morale in South Vietnam by punishing North Vietnam, the source of the suffering in the South, and (e) to reduce criticism of the Administration from advocates of a bombing program.
2. Achievement of major purposes. The potential targets, targets struck and per cent of destruction are shown at Tab A. In terms of the purposes of the program, its results have been as follows:
- a.
- To promote a settlement. Obviously, this objective has not yet been attained. We recognized at the start of the program, as we do now, that the influence of the bombing on a settlement would not be great until the North Vietnamese had been disappointed in their hopes for a quick military success in the South. There is no doubt that the bombing program has become an important counter in the current tacit and explicit bargaining [Page 281] process and will be an important counter in any future bargaining.
- b.
- To interdict infiltration. It is believed that regular North Vietnamese units now in South Vietnam (estimated to be one division) require about 4 tons of supplies daily for the “current” level of combat but would require 67 tons of supplies daily for “light” combat. (“Current” levels are operations conducted largely in small units; “light” combat would involve larger elements in action on the average of every third day, with expenditures of one-third of each unit’s basic load of ammunition on each action.) It is believed that regular North Vietnamese units and Pathet Lao forces in the Laos Panhandle require about 21 and 51 tons daily respectively for the two levels of combat. Viet Cong arms, ammunition and other supply requirements are estimated at 8 tons daily for “current” combat and 115 tons for “light” combat. The effect of the interdiction program on the movement of supplies is summarized below:
The 440-ton per day rail traffic from Hanoi south to Vinh has been cut off at Ninh Binh (40 miles south of Hanoi). Supplies still move by sea and over the parallel highway system. The latter has been badly damaged and is subject to armed reconnaissance; sea traffic into SVN is under surveillance. At a minimum, supply is slower and less regular and delivered at increased cost in resources and energy expended. Roads into Laos have been subjected to similar interdiction and armed recce. Only limited interdiction has been imposed on the key rail and road net northwest of Hanoi, and none on the railway net northeast of Hanoi; and port destruction has been minimal. Thus, substantially uninterrupted supply continues from China by rail into Hanoi and by sea into Haiphong to meet major North Vietnamese military, industrial and civilian needs.
The effect of the bombing on military operations is estimated to have been as follows:
- (1)
- For regular North Vietnamese and Pathet Lao forces. The interdiction program has caused North Vietnam increasing difficulty in supplying their units in Laos and South Vietnam. How severe this difficulty is or how stretched North Vietnam’s supply capabilities are cannot be estimated precisely. Our interdiction efforts may have either prevented or deterred the North from sending more troops than they already have. The interdiction programs in North Vietnam and Laos also may have influenced a Communist decision to forego a 1965 offensive in Laos.
- (2)
- For Viet Cong forces. Because the VC require significantly less infiltrated arms and ammunition and other supplies than do the North Vietnamese and Pathet Lao forces, the interdiction program probably has had less of an adverse effect on their operations. By raising VC fears concerning adequacy of supplies, however, the program may have caused the VC summer offensive to be less intense, aggressive and unrelenting [Page 282] than it would otherwise have been. It should be noted that the program has not been a “strategic” bombing program; it has been limited to selected targets of fairly direct military relevance. Populations and targets such as dikes and basic industries have not been struck. Furthermore, the immediate vicinities of Hanoi and Haiphong have been avoided, partly because the targets there are primarily of the “strategic” type and partly because strikes there would involve even more serious risks of confrontations with the Soviet Union and China.
3. Other effects of the program.
- a.
- Deterrence of VC terrorism. There is no evidence that strikes against North Vietnam have affected one way or another the level or kind of VC incidents of terror in South Vietnam.
- b.
- Morale in South Vietnam. Morale in South Vietnam was raised by the initiation of the bombing program (as, later, by the deployment of additional troops). Now—with the bombing programs having become commonplace and with the failure of the situation to improve—morale in South Vietnam is not discernibly better than it was before the bombing program began. In a sense, South Vietnam is now “addicted” to the program; a permanent abandonment of the program would have a distinct depressing effect on morale in South Vietnam.
- c.
- Reduction of criticism of the Administration. Some critics, who advocated bombing, were silenced; others are now as vocal or more vocal because the program has been too limited for their taste. The program has generated a new school of criticism among liberals and “peace” groups, whose activities have been reflected especially in teach-ins and newspaper criticisms.
- d.
- Damage to peaceful image of the US. The price paid for improving our image as a guarantor has been damage to our image as a country which eschews armed attacks on other nations. The hue and cry correlates with the kind of weapons (e.g., bombs vs. napalm), the kind of targets (e.g., bridges vs. people), the location of targets (e.g., south vs. north), and not least the extent to which the critic feels threatened by Asian communism (e.g., Thailand vs. the UK). Furthermore, for a given level of bombing, the hue and cry is less now than it was earlier, perhaps to some extent helped by Communist intransigence toward discussions. The objection to our “warlike” image and the approval of our fulfilling our commitments competes in the minds of many nations (and individuals) in the world, producing a schizophrenia. Within such allied countries as UK and Japan, popular antagonism to the bombings per se, fear of escalation and belief that the bombings are the main obstacle to negotiation, have created political problems for the governments in their support of US policy.
- e.
- Pressures to settle. More countries are now, as a consequence of the bombing program, more interested in taking steps to help bring the war to an end.
- f.
- Impact on US-Soviet detente. The bombing program—because it appears to reject the policy of “peaceful co-existence,” because it involves an attack on a “fellow socialist country,” because the Soviet people have vivid horrible memories of air bombing, because it challenges the USSR as she competes with China for leadership of the Communist world, and because US and Soviet arms are now striking each other in North Vietnam—has strained the US-Soviet detente, making constructive arms-control and other cooperative programs more difficult. How serious this effect will be and whether the detente can be revived depend on how far we carry our military actions against the North and how long the campaign continues. At the same time, the bombing program offers the Soviet Union an opportunity to play a role in bringing peace to Vietnam, by gaining credit for persuading us to terminate the program. There is a chance that the scenario could spin out this way; if so, the effect of the entire experience on the US-Soviet detente could be a net plus.
- g.
- Risk of escalation. The bombing program—especially as strikes move toward Hanoi and toward China and as encounters with Soviet/Chinese SAMs/MIGs occur—may increase the risk of escalation into a broader war.
4. The future of the program. Even with hindsight, I believe the decision to bomb the DRV was wise and I believe the program should be continued. The future program should:
- a.
- Emphasize the threat. It should be structured to capitalize on fear of future attacks. At any time, “pressure” on the DRV depends not upon the current level of bombing but rather upon the credible threat of future destruction which can be avoided by agreeing to negotiate or agreeing to some settlement in negotiations.
- b.
- Minimize the loss of DRV “face.” The program should be designed to make it politically easy for the DRV to enter negotiations and to make concessions during negotiations. It may be politically easier for North Vietnam to accept negotiations and/or to make concessions at a time when bombing of their territory is not currently taking place.
- c.
- Optimize interdiction vs. political costs. Interdiction should be carried out so as to maximize effectiveness and to minimize the political repercussions from the methods used. Physically, it makes no difference whether a rifle is interdicted on its way into North Vietnam, on its way out of North Vietnam, in Laos or in South Vietnam. But different amounts of effort and different political prices may be paid depending on how and where it is done. The critical variables in this regard are (1) the type of targets struck (e.g., port facilities involving civilian casualties [Page 284] vs. isolated bridges), (2) type of aircraft (e.g., B-52s vs. F-105s), (3) kind of weapons (e.g., napalm vs. ordinary bombs), (4) location of target (e.g., in Hanoi vs. Laotian border area), and (5) the accompanying declaratory policy (e.g., unlimited vs. a defined interdiction zone).
- d.
- Coordinate with other influences on the DRV. So long as full victory in the South appears likely, the effect of the bombing program in promoting negotiations or a settlement will probably be small. The bombing program now and later should be designed for its influence on the DRV at that unknown time when the DRV becomes more optimistic about what they can achieve in a settlement acceptable to us than about what they can achieve by continuation of the war.
- e.
- Avoid undue risks and costs. The program should avoid bombing which runs a high risk of escalation into war with the Soviets or China and which is likely to appall allies and friends.