The theory was to arrange a series of offensive actions in a stairstep progression of increasing violence, then ascend the stairs a step at a time, pausing long enough at each level to give the enemy time for reflection. Surely, he would accept reasonable terms long before the reaching of the highest levels of violence. The idea looked good in theory, but in practice—in Southeast Asia—it left something to be desired.
One way of going to war is to engage the enemy little by little. Airplanes, for example, might drop 10 bombs today, 20 tomorrow, and 40 the day after; hit jungle trails first, rail nets second, and industrial plants third; strike just over the border initially but fly deeper into enemy airspace on each successive raid. This could be called a strategy of graduated pressure—or of “gradualism” or “escalation.”
Such a strategy violates military principles. It sacrifices shock effect. It telegraphs punches to the enemy and gives him time to take counteraction. It invites defeat.
Yet, today, graduated pressure, for all its deficiencies, appeals to a great many people as the safest way to skirt the perils of the nuclear age—which explains, no doubt, why the United States used it in the bombing of North Vietnam.
That unique air campaign began on 7 February 1965, when 45 carrier-based planes hit minor targets just north of the Demilitarized Zone in a deliberately low-key operation. The ensuing weeks and months brought a Progressive buildup in the weight of attack, periodic additions of new targets to the list, and a step-by-step expansion of the geographical area under attack. One object of such a campaign, said the Air Force Chief of Staff, General John P. McConnell, a few months after it began, was “to apply pressure in measured steps until the enemy is willing to negotiate a mutually acceptable settlement of the conflict.”
U. S. land-based and carrier-based bombers pounded the North for three years. The theoretical model of gradually increasing pressure proved difficult to apply in practice, since weather and politics frequently intervened to slack off the pressure. But, despite variations in the rate and severity of attack, the progress charts showed a generally rising curve of cumulative bomb tonnage that eventually went well above the half-million tons dropped in the Pacific theater during World War II. Finally, in the spring of 1968, Hanoi came to the conference table. The inexorable turning of the screw had paid off. Or had it?
For the considerable damage inflicted on North Vietnam, the United States had paid no small price—in the dollar cost of the air offensive, in the combat losses of some 900 aircraft along with many of their crews and, most of all perhaps, in the deterioration of public support for American policy at home and abroad. After the curtailment—and later the cessation—of air attacks on the North, fighting continued in the South, and the Paris talks dragged on with little visible progress toward a settlement. The situation, though not unexpected, did raise the question as to whether it was Hanoi or Washington that had, in the end, found the mounting price of the air attacks prohibitive.
Most of the blame for the real and imagined shortcomings of our campaign fell upon former Secretary of Defense Robert S. MacNamara [sic], but the basic conception came long before his time in the aftermath of the world’s first thermonuclear explosion on 1 November 1952. The tremors from that mighty blast, attenuated by Russia’s growing power and unabating hostility, built up a huge ground swell of intellectual activity in the field of military strategy.
The matter of how to fight wars had never been a very popular one for scholarly study, but now the academic community, possibly encouraged by government grants, turned to it with energy if not enthusiasm. The trickle of strategic analyses soon became a torrent. In the first 15 years of the hydrogen bomb era, academicians very likely turned out more such material than had been written in the 300 prior years since the founding of the first college in America.
The new civilian strategists, as well as their military counterparts, focused initially on the problems of surprise attack and massive retaliation. However, as nuclear weapons multiplied and a deliberate resort to general war seemed to become less likely, they turned more and more to the problem of keeping small wars from growing into big ones.
Under what conditions might a limited conflict get out of hand? Most analysts thought the greatest danger lay in those situations where a major power was threatened by some dramatic action by the other side. Indeed, many feared that, in a period of crisis, the mere momentum of swiftly paced events would alone suffice to carry the antagonists over the brink.
The assumed causes of the malady pointed logically to the remedies: limit our war objectives, they said, making sure the enemy knows we do not seek his “unconditional surrender;” keep hostilities at the lowest possible level; avoid precipitous actions; slow down the pace of military operations to allow time for negotiations. “It must be the task of our military policy,” wrote Professor Henry A. Kissinger as early as 1956, “to develop a doctrine and a capability for the graduated employment of force.” This we did—slowly in the Eisenhower administration, more quickly under President John F. Kennedy.
The Cuban missile crisis of 1962 gave fresh impetus to the idea. The United States moved its land, sea, and air units around like chessmen on a board, gradually closing off options available to the Soviet Union. The favorable resolution of that crisis gave the nation a glow of renewed confidence and encouraged the graduated pressure theorists to push their concepts a bit further.
The meaning of “escalation” shifted, in popular usage, from an unintended to a deliberate expansion of hostilities. Herman Kahn showed in his book, On Escalation, how one side might gain a bargaining advantage in limited war by raising the violence to progressively higher levels where the other side could not or would not follow. Thomas C. Schelling, another well-known academic strategist and evocative phrase-maker, wrote of the new “diplomacy of violence” with its “coercive warfare” and “compellent campaigns.” He suggested that the primary role of military power was no longer to defeat an opponent but to hurt him—to inflict pain for purposes of persuasion. These and other post-Cuba strategic analyses reflected—or perhaps they inspired—a growing conviction among government officials that the United States could control or “manage” future international crises by co-ordinating the diplomatic finesse of its statesmen with the “flexible response” of its armed forces.
The aim of conflict management was to end wars on acceptable terms at the lowest possible level of violence. The method was simple. Arrange a series of planned offensive actions in a stairstep progression of increasing violence, then ascend the stairs a step at a time, pausing long enough on each level to give the enemy time for reflection. No single act alone would be overly threatening or provocative but, as one step followed another, the enemy would see his plight steadily worsening and his prospects of ultimate victory fading. He would recognize the futility of continued resistance and accept reasonable terms long before the war reached higher levels of violence. Lives would be saved and the risk of uncontrolled escalation would be kept to a minimum. The idea looked good in theory but in practice—in Vietnam—it left something to be desired.
Was our bombing campaign in Vietnam a success or failure? We know it did not force a settlement of the conflict, but neither did it start World War III, as some of the proposed alternatives conceivably might have done. What it did do is uncertain and must remain so until there is more information available, especially from the other side—including Moscow and Peking, as well as Hanoi. On the basis of present evidence, it does appear that we expected a big return from a small investment and got instead a small return from a big investment.
If our expectations were indeed too high, they may have been so because of two false assumptions implicit in most writings on graduated pressure theory in the mid-1960s. One was the assumption that a gradual increase in bombing would produce a correspond gradual increase in pressure on the enemy. The other was the assumption that the United States would, since it obviously could, continue increasing the scale of bombing as long as necessary to achieve its objective. The first error came from misconstruing the military effects of bombing in general; the second from not foreseeing the political vulnerability of this particular bombing campaign.
Aerial bombardment exerts both psychological and physical pressures on the enemy. Psychological pressure weakens his will to wage war by arousing fear, panic, discouragement, and defeatism among his people. Physical pressure reduces his capacity to wage war by destroying his fighting forces or the logistic, industrial, and economic resources required to support them. The two kinds of pressure may fluctuate widely during the course of an air campaign. At some particular time one may be great, the other small; one increasing, the other decreasing. The lack of any precise way to measure these pressures, much less to forecast them, presents one of the most difficult problems in air strategy.
The psychological effects on a government or a people are especially capricious and unpredictable since they are more the product of expectations than of experience. The mere threat of German bombs had placed Britain under intense psychological pressure before Chamberlain went to Munich in 1938. Yet, two years later, when bombs actually started falling on England, the psychological pressure eased off even as casualties and physical damage soared. Britons, relieved to find the air raids less fearsome than expected, now concluded, with more emotion than logic, that they could take anything Hitler could deliver.
Physical pressure on the enemy would be fairly easy to measure if it was directly proportional to the amount of physical destruction inflicted on him—to the number of air raid casualties, for example, or to the monetary value of property destroyed, or to some other quantitative measure of actual bomb damage. Unfortunately, this is not the case. Pressure and destruction are clearly related but they do not go hand-in-hand throughout the course of an extended conflict. In a graduated pressure campaign, destruction would mount steadily after the first day of war; however, the onset of real pressure might be long deferred. This is because a nation under attack ordinarily has a substantial reserve or “cushion” in its war economy as well as in its military logistic system. This cushion must be deflated by one means or another before the physical pressure of bombing can become truly decisive.
During World War II, as Allied air attacks on Germany increased in size and efficiency, the cumulative bomb damage became immense. But at the same time the Nazi regime made large-scale readjustments. It discontinued unneeded civilian activities, transferred workers to war-supporting services and industries, repaired damaged facilities, and carried out industrial dispersion. By such measures the German people were able to continue essential war production. Indeed, in certain categories of war goods, they repeatedly posted new production peaks despite the growing magnitude and severity of physical destruction. However, the grinding attrition of war eventually reduced the cushion so that, in the closing months of the conflict, losses became irreplaceable, production of war supplies plummeted, acute shortages developed, and the entire economy approached the point of collapse. This was the long-awaited pay-off of nearly five years of bombing.
In the field of strategy, the critical point to be aimed at in attacking large strategic or tactical interdiction target systems, is that at which the rate of bomb damage surpasses the rate at which the enemy can replace or restore losses of essential goods and services. Short of this point, air strikes only inconvenience him; beyond it, they destroy him. This turning point is somewhat comparable to that in a submarine campaign when cumulative ship sinkings have reduced the enemy’s sealift capability below his minimum requirements. Thereafter, the military pressure exerted by the submarine force increases sharply and decisively.
To illustrate bombing effects schematically, let us suppose we could actually measure the combined physical and psychological pressure exerted on the enemy at various stages of an air campaign. If we then plotted these measurements on a graph, of the sort depicted in Figure 1, how would the pressure change with the passage of time? Would it increase smoothly and uniformly along the dotted line from D-day to V-day? In earlier discussion, we have contended that it would not and have suggested instead that the changing pressure would trace out some such curve as shown by the solid line, dropping off sharply from an initial peak at the start of hostilities, crossing a valley of variable width, then rising steeply to a second higher peak at the end of the war.
[Figure 1]
The first peak would represent the psychological pressure exerted by the mere threat of bombing. If this initial pressure was great enough to force an acceptance of terms before the first bomb was dropped, as in the case of Germany’s pressure on Britain at Munich, there would be no war. However, if we assume that the initial pressure is insufficient to deter war, what happens when the first small-scale air attacks actually begin? There are two possibilities. The pressure may rise abruptly to the decisive level if the attacker manages to convey the impression, in his initial strikes, that he can and will escalate the bombing to whatever level is required to achieve his aims. On the other hand, if the defender thinks he can absorb all the punishment the attacker is able or willing to inflict, the war continues and a wholly new set of factors came into play.
No subsequent attack with conventional bombs, however destructive, is likely to have the shock effect of the first one. The psychological pressure will ease off. Moreover, the physical pressure will not necessarily increase despite mounting bomb damage. The defender may very well become stronger instead of weaker as the attacks continue. He would do so by falling back on the cushion in his war economy, exploiting his untapped manpower and industrial potentials, and restructuring his organization, facilities, and patterns of operation to reduce his own vulnerability and to complicate the problems of his attacker. The air war would evolve into a struggle of attrition in which the defender tries to conceal, protect, restore, or replace key elements of his war potential faster than the attacker can find and destroy them. On the one side there is a steady increase in the numbers of bombs delivered, sorties flown, and targets of various kinds attacked; on the other, a parallel growth of camouflage, concealment, dispersal, deception, and also, perhaps, of active antiaircraft defenses.
In seeking to analyze the nature and effect of a bombing campaign, one must guard against oversimplification. In saying, for example, that the pressure of bombing reached a decisive level, we do not mean to imply that bombing was necessarily the sole or even the most important cause of the pressure. There are many other important influences at work on a government in wartime—political, economic, and psychosocial—that may tend to strengthen or weaken the military pressure of bombing. And in the military sphere, air operations do not occur in isolation but are set in the context of a larger military effort.
The character and scope of surface military and naval operations may have a profound effect on the results achievable with an air offensive. In World War II, the enormous logistic demands of the fighting fronts in Russia and the West helped reduce the cushion in the German war economy. Likewise, naval action constricted Japan’s access to essential raw materials while the threat of land invasion multiplied her military production requirements. By tightening the squeeze on the war resources of both countries these land and naval operations made the air attacks increasingly effective.
On the other hand, the absence of any comparable squeeze on North Vietnam made air attacks there much less rewarding. That country did not face a serious threat of land invasion. The guerrilla warfare it conducted in the South required far less logistic support than would an active conventional fighting front. Basically a consumer and transshipper—not a producer—of war goods, North Vietnam was in no way dependent upon its own limited industrial resources. For policy reasons, the United States declined to interfere with the seeming inexhaustible flow of external support, arriving mainly by sea. Under these circumstances, available targets were relatively unproductive and the air offensive leveled off on a scale of attack that a determined, resourceful foe might well decide he could withstand indefinitely.
Had the bombing continued to increase in scope and intensity, while military pressure was maintained in the South, the resultant squeeze must eventually have brought us to the point of payoff (D + X in Figure 1). However, this would have meant securing by pure compulsion what we obviously intended and expected to secure by persuasion. Also, it would have meant inflicting far more damage and casualties on the North than anyone anticipated when our attacks began. The strategy of graduated pressure was supposed to resolve conflicts long before they ever reached higher levels of destruction.
When theorists said explicitly that we should use only the minimum force required, they assumed implicitly that the force required would be small. James C. Thomson, a former Department of State official, said of air strike planners in the late autumn of 1964: “There were those who actually thought that after six weeks of air strikes, the North Vietnamese would come crawling to us to ask for peace talks. And what, someone asked in one of the meetings of the time, if they don’t? The answer was that we would bomb for another four weeks and that would do the trick.”
How this would come about was based on a kind of syllogism: the enemy knows a massive nuclear attack would defeat him; our military capabilities cover the spectrum from small conventional raids to a massive nuclear attack; therefore, small conventional raids, reflecting our determination and intent, would show the enemy that his defeat was inevitable. He would recognize the futility of prolonging a war he could not hope to win. He would agree to an early settlement as a matter of practical self-interest.
One fallacy in this line of reasoning was the inference that we would really exercise our vast military power throughout its range “if necessary.” In some wars we would undoubtedly do so, but there are many different kinds of war and they vary a great deal in importance. One war may be a struggle for national survival, another simply the performance of a disagreeable duty, and others of many different gradations in between. In each case it is the political interests of the state rather its military capabilities that will, in the end, determine how a war is to be prosecuted. From a purely military standpoint, for example, nuclear weapons would be enormously useful against an opponent who had none of his own; but, from a political standpoint, it seems quite unlikely that the United States would use any kind of nuclear weapon, no matter how small, in a limited war. Yet some of our contingency planners apparently still cling to the obsolete notion that a nuclear response is an available option for dealing with minor aggression. If so, they deceive themselves more than the enemy.
The late B. H. Liddell Hart once said that a “lesson of strategy, which should be a pillar of policy, is the importance of putting ourselves in the other’s shoes and looking at every step from the other’s standpoint before we take the step.” With this thought in mind, let us imagine for a moment that we are the masters of a small state on the receiving end of a gradually increasing U. S. air attack. How might we evaluate that situation?
We know that our powerful opponents could, in a manner of speaking, “knock us out overnight.” However, this is highly improbable under their form of government and with their past history of restraint. So the question that really concerns us is not “How far the Americans go?” but rather “How far will they go?” and, in that connection, “How much can we take?”
The first small-scale raids have already shown us we can take more than we thought. Moreover, we are learning new ways to limit the effects of bombing and thus extend our powers of resistance. But will the military pressure eventually be too much for us? Reading between the lines, we find that our opponents practically assure us they will not use nuclear weapons, not bomb our population centers, not interdict our external support, and not invade our territory. Believing that we can cope with the remaining military threat and that time is on our side politically, we decide to try to outlast them. And so it was, perhaps, that the leaders in Hanoi decided rightly as later events indicated, that the United States would not escalate the bombing of North Vietnam to intolerable proportions.
We have seen that a slow escalation of bombing does not, in the beginning, gradually and progressively weaken the enemy but will, if continued, ultimately reach a point of payoff and thereafter weaken him quite rapidly. Meanwhile, however, political factors may come into play, especially in a limited war situation, which would make it impractical to carry the bombing campaign that far. As a result, a strong nation may find itself unable to exploit its air superiority against a weaker foe. But despite these drawbacks, the strategy of graduated pressure—or some variant of it—will very likely be retained for lack of an acceptable alternative.
Consider, for example, the alternative proposed by Admiral U. S. Grant Sharp, U. S. Navy (Retired), Commander-in-Chief, Pacific, from 1964 to 1968. Discussing the bombing of North Vietnam in an article in the May 1969 Reader’s Digest, he said: “If we had launched a maximum-effort air campaign—coupled with heavy pressure on the enemy’s troops in South Vietnam—it would not have been long before he would have been forced to ask for negotiations.” As to the possibility that such a course might have risked a nuclear confrontation with the Soviet Union, he said; “Personally, I believe the risk was minimal; in any case, a nation which is not willing to take calculated risks to achieve its objectives should never go to war in the first place.”
Certainly a bold massive stroke is more promising of military success than piecemeal nibbling. Also, a decisive victory would seem more likely to end a war than to broaden it. In fact, most of our experience in air warfare would lend support to Admiral Sharp’s view. Yet, one must have serious doubts that the bolder course he advocates will gain acceptance—not because it is wrong but because it makes insufficient allowance for the widespread fear of a general nuclear war—a fear that General Maxwell D. Taylor, U. S. Army (Retired), and others have cited as one of the most important factors likely to influence our future military strategy.
Final decisions on what constitutes risk, and how much of it to take, are made at the national level—and properly so—by civilian rather than military leaders. The course they choose will likely hew close to the center line of the passage between nuclear holocaust on one side and pre-emptive surrender on the other, without any adventurous excursions in either direction. Within the allowable limits of maneuver, military and naval strategists must somehow devise a workable compromise between contradictory requirements: on the one hand, the political preference for caution, deliberation, and restraint to avoid undue provocation; and on the other, the military need for boldness, speed, and shock to prevail in battle. The task will be challenging to say the least.
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A graduate of the U. S. Military Academy with the Class of 1938 and a rated pilot since 1939, Colonel Sights served during World War II in flying and aerial gunnery training programs and subsequently in a B-29 bomber unit in the Marianas. Postwar assignments included duty as politico-military affairs staff officer at Headquarters U. S. Air Force, faculty group director at the Armed Forces Staff College and, prior to his retirement in 1965, research associate at the Aerospace Studies Institute, Air University. Now residing in Arlington, Virginia, he has contributed articles on military history and strategy to various professional journals including Air University Review, NAVAL REVIEW, and Air Force and Space Digest.