5 (page 62)p. 62The legacy of Clausewitz

Clausewitz's modest ambition to write a work that ‘would not be forgotten after two or three years’ at first showed little sign of being fulfilled. The edition of his works that his widow published in 1832, the year after his death, was received with respect but made little impact. In 1867 a survey of military literature in Europe made the damning comment that Clausewitz was ‘well-known but little read’. On War might have been a forgotten curiosity had not Helmuth von Moltke, the acknowledged architect of Prussia's military triumphs over Austria and France and so, with Bismarck, the creator of the united German Empire in 1871, let it be known in the aftermath of his triumph that, apart from the Bible and Homer, Clausewitz was the author whose work had influenced him most.

With Moltke's endorsement, Clausewitz instantly became fashionable. In 1873 a German military journal, taking its cue from the top, pronounced that ‘Clausewitz has earned his place as the foremost authority on military learning in the German army’. The wars of 1866 and 1870, it said, had shown how ‘strong discipline, good weapons, appropriate elementary tactics, good march dispositions, railways, practical supply arrangements and communications determine everything in war. This purely craftsmanlike concept which is so widespread in the army and has effected such a transformation, is the consequence of Clausewitz's ingenious destructive activity.’ (page 63)p. 63What Clausewitz had destroyed was the formalistic strategy of manœuvre that had been generally taught in staff colleges before 1870, its dominance assisted by the longevity of the influential Jomini, who died only at the age of 90 in 1869, and whose well-organized didactic textbooks had been translated into every major European language. Jomini's teaching directly moulded the doctrines of the French, the Russian, and the American Armies, and through his influence on W. von Willisen in Prussia and E. B. Hamley in England much of the thinking of those armies as well. ‘But for Clausewitz, Jomini would probably have been Moltke's guiding spirit’, wrote a later authority, Rudolf von Caemmerer, with something like horror: ‘[He] freed us from all that artificiality which gave itself such airs in the theory of war and has shown us what, after all, is the real point.’

Moltke had been a pupil at the War College in Clausewitz's time, but had no contact with him there, and according to his biographer Eberhard Kessel there is little evidence from his diaries and letters that he had studied his work very deeply. Clausewitz's ideas about the importance of moral forces, the desirability of seeking out the enemy and destroying him by battle, the need for flexibility and self-reliance and concentration were fairly commonplace in the Prussian Army after 1815. Indeed they were particularly characteristic of the more liberal-thinking and forward-looking young officers of the time, in contrast to the formalistic strategic concepts being reimposed by the conservative hierarchy. Moltke only absorbed from Clausewitz and passed on to his own disciples those ideas that coincided with his own. The image of Clausewitz that was transmitted to the German Army, and indeed to the world in the latter half of the nineteenth century, was transmitted through Moltke almost as totally as the image of Marx was transmitted to the Russian peoples through Lenin. It was not inaccurate but it was distorted and very incomplete.

Moltke's own writings echo Clausewitz to the point of plagiarism.

(page 64)p. 64Victory through the application of armed force is the decisive factor in war. Victory alone breaks the will of the enemy and compels him to submit to ours. It is not the occupation of a slice of territory or the capture of a fortress but the destruction of enemy forces that will decide the outcome of the war. This destruction thus constitutes the principal object of operations.

It is a mistake to believe that one can lay down a plan of campaign and follow it through point by point from beginning to end. The first encounter with the main enemy will create … an entirely new situation. To appreciate precisely the changes which events have effected on the situation, take the desired measures in a relatively short time and execute them with all desirable resolution is all the General Staff can do.

Strategic doctrine hardly extends beyond the first principles of common sense … Its value lies almost wholly in its concrete application.

In war it is less important what one does than how one does it. Strong determination and perseverance in carrying through a simple idea are the surest route to one's objective.

These ideas were disseminated by a whole generation of German strategic writers in the two decades after 1870, many of whom had served on Moltke's staff. ‘It would be to misunderstand the nature of strategy to try to transform it into a predetermined scientific system’, wrote one of the most eminent, Verdy du Vernois, ‘… Precision in conception, energy in the execution of one's plan, these are the pilots most capable of steering us through all the reefs.’ And this simplicity in planning, this energy in execution, had to be complemented by a readiness at all levels to take responsibility. ‘Everyone’, wrote Verdy, ‘must hold the conviction that it is better to advance on one's own responsibility than to remain idle, waiting for orders.’ All of which led Verdy and his generation to the conclusion that ‘military qualities are rooted rather in character than in knowledge’: a perfect Clausewitzian (page 65)p. 65formulation, and one which professional military men have loudly echoed ever since.

This was the selection of Clausewitzian ideas that dominated the German Army at the beginning of the twentieth century. The French took a little longer to discover the virtues of their enemy's principal mentor, but by 1900 there was in the French Army what has been described as ‘a veritable craze [engouement] for Clausewitz’. There were those who maintained that Clausewitz was only expressing with typical teutonic obscurity what Napoleon had stated with far greater clarity and force, but the whole emphasis upon ‘moral forces’ fitted in perfectly not only with the traditions of the French Army itself, antedating the Revolution and recently reinforced by its experience of colonial warfare, but with the philosophy of élan vital which was being made fashionable by the philosopher Henri Bergson (1859–1941). Clausewitz's most influential disciple in France was the future Marshal Ferdinand Foch, whose Principles of War, published in 1903, contained virtually an abstract (not always acknowledged) of Clausewitz's views. Defeat, he there argued, ‘is in fact a purely moral result, that of a mood of discouragement, of terror, wrought in the soul of the conquered by the combined use of moral and material factors simultaneously resorted to by the victor’. It was not a bad diagnosis, as was to be borne out by the events of September 1914 when General Joffre, in spite of having suffered defeats on the frontiers that made the battles of 1870 look like small-scale skirmishes, kept his head, refused to be panicked and counter-attacked on the Marne; something that his successor in 1940, General Gamelin, notably failed to do.

But Joffre's initial defeats had been due to imprudent and premature offensives, and in launching those offensives he was only doing the same as every other general in Europe. How did Clausewitz's disciples in 1914 reconcile their admiration for his teaching with their ignoring of his explicit doctrine that defence was the stronger form of war – a doctrine which the development of firearms since Clausewitz's death had so (page 66)p. 66powerfully reinforced? Moltke himself had taken this seriously into account even in the 1860s, developing a doctrine of ‘strategic offensive, tactical defensive’ to enable his infantry to maximize the advantages of their new breech-loading rifles. Forty years later, when rifles had not only tripled their range, accuracy, and rate of fire but been reinforced by machine-guns, Foch found arguments in other pages of On War to justify his belief in the superiority of the offensive.

To fall on, but to fall on in numbers, in masses: therein lies salvation. For numbers, provided we know how to use them, will allow us, by means of the physical superiority placed at our disposal, to get the better of the violent enemy fire. Having more guns we will silence his own; it is the same with rifles, the same with bayonets, if we know how to use them all.

The best strategy in short was to be very strong; first generally and then at the decisive point.

Clausewitz's teaching about the primacy of the defensive was regarded by pre-1914 strategists as an embarrassment, to be ignored or explained away. His biographer von Caemmerer wrote in 1905, of his definition of defence as ‘the stronger form with the negative object’, that ‘the more or less keen opposition to this sentence never ceases’. The most widely read of all German strategic writers, Colmar von der Goltz, in his popular work The Nation in Arms (1883), argued that if Clausewitz had lived to revise his text he would have changed his mind on this point, since it was incompatible with his teaching about the destruction of the enemy. ‘He who stays on the defensive does not make war, he endures it’, argued von der Goltz; ‘… Happy the soldier to whom fate assigns the part of the assailant!’

Strategists before 1914 were in fact increasingly hypnotized by the Clausewitzian and Napoleonic idea of the decisive battle for the overthrow of the enemy, that Vernichtungsschlacht to which Clausewitz (page 67)p. 67had devoted so many pages. So not only was Clausewitz's teaching about the primacy of the defensive abandoned, but also the idea, even more central to his theory, of the two types of war. Any possibility that war in Europe could be anything other than total had by 1900 become discounted. Von der Goltz expressed a view general among his countrymen when he wrote:

If two European Powers of the first order collide, their whole organised forces will at once be set in motion to decide the quarrel. All political considerations, bred of the half-heartedness of wars of alliance, will fall to the ground … All moral energy will be gathered for a life and death struggle, the whole sum of the intelligence residing in either people will be employed for their mutual destruction.

And that this was not a purely German view one can see by turning to Foch: ‘You must henceforward go to the very limits to find the object of war. Since the vanquished party never now yields before it has been deprived of all means of reply, what you have to aim at is the destruction of those means of reply.’

But if war was henceforth to be total, what became of Clausewitz's dogma that it was only an instrument of policy and that the military leadership must take its cue from its political leaders? This was an aspect of Clausewitz's teaching too basic for anyone to ignore, and the rivalry between Moltke and Bismarck over the direction of strategy in 1870 had provided a notorious example of the problems that it created. Goltz did not ignore it, but he found an ingenious solution:

War is always the servant of policy … without a sound policy, success in war is improbable. War will on that account be in no way lowered in importance … if only the commander in chief and the leading statesmen are agreed that in all circumstances war serves the ends of politics best by a complete defeat of the enemy.

(page 68)p. 68That left the statesmen little choice. The same view was being expressed decades later beyond the Rhine by the French military historian Jean Colin, whose book The Transformations of War was published in 1911:

The mutual conditions of modern war no longer admit of avoidance of the radical decision by battle. The two armies occupying the whole area of the theatre of operations march towards each other, and there is no issue but victory. Therefore the indications which a government should give to a general on the political object of war are reduced to a very small affair. Once the war is decided upon, it is absolutely necessary that a general should be left free to conduct it at his own discretion, subject to seeing himself relieved of his command if he uses his discretion with but little energy and competence.

All these prophecies were to be self-fulfilling. The social and material conditions of Europe in the early twentieth century had indeed produced armed forces for whom the fighting of ‘limited wars’ was simply not possible. Even if the activities of these armies had been susceptible to the kind of fine tuning that Clausewitz had so admired in Frederick the Great, ‘the passions of the peoples’, that third element in Clausewitz's ‘remarkable trinity’, would have made it impossible. The spread of democratic ideas had made nations more bellicose rather than less and had, as Clausewitz had foretold, increased the totality of the wars they fought, bringing them nearer to his idea of ‘absolute war’. Clausewitz's critics, such as Liddell Hart, were later to blame his influence for the destructive way in which the First World War was conducted, especially on the Western Front; for the lack of subtlety in strategic thinking, the implacable determination of military leaders to gain their objectives whatever the cost, their almost joyful acceptance of heavy casualties as an indication not of military incompetence but of moral strength. Clausewitz's defenders could reply that, given the issues that were seen to be at stake, the war could only be settled by just such a ‘trial of moral and physical forces by means of the latter’, and (page 69)p. 69no amount of military skill could have attained the political objects – the preservation or destruction of the Habsburg Empire, the establishment or prevention of a German hegemony in Europe, the maintenance of British maritime supremacy, and the territorial integrity of France – any more cheaply. But Clausewitz himself might have reminded us of those passages in which he related the conduct of war to its social environment, pointing out how

every age had its own kind of war, its own limiting conditions, and its own peculiar preconceptions … It follows therefore that the events of every age must be judged in the light of its own peculiarities. One cannot therefore understand and appreciate the commanders of the past until one has placed oneself in the situation of their times.

(p. 593)

The First World War was conducted as it was, not because the major military figures happened to have read Clausewitz, but because it was so determined by the social and political structure of their epoch. Clausewitz's prescription for the conduct of war, certainly as interpreted through Moltke and his disciples, is indeed open to legitimate criticism, but his descriptive analysis can hardly be faulted.

This, of course, was the aspect of Clausewitz's teaching that had so impressed Marx and Engels, and was to influence in their turn both Lenin and Trotsky. War was an instrument of policy and policy was the product of certain basic social factors that had to be grasped before any valid military doctrine could be worked out. The tenets of Marxist-Leninism, it was and is believed, made possible a scientific insight into these ‘objective factors’. The frequent and flattering references to Clausewitz that are to be found in Lenin's writings were to make his ideas acceptable to Marxist-Leninists in spite of his bourgeois militarist background, much as Aquinas's homage to Aristotle made that pagan philosopher acceptable to the medieval Church. The new army reconstituted by the Soviet Union after the Revolution and the Civil War thus took the Clausewitzian doctrine about the relationship of war to (page 70)p. 70policy as the foundation for its own military thinking; and few Soviet military textbooks did not contain at least a passing reference to it.

In the West however after 1918 this aspect of Clausewitz's teaching was regarded as being as sinister as his strategic doctrine was disastrous. To British and American liberals the much-quoted and misquoted aphorism ‘War is the continuation of policy by other means’ was regarded not as a piece of serious political analysis but as shocking evidence of militaristic cynicism. As for his strategic doctrine, it was condemned especially strongly by British thinkers who believed that they had discovered a more effective and humane means of conducting war than through the blood-baths to which the uncritical acceptance of Clausewitz's teaching by continental theorists appeared to have led.

Even before 1914 the absence from Clausewitz's work of any consideration of maritime or economic war had been noted and criticized in Britain. Soon after the beginning of the century, however, the growing possibility of a war with Germany set on foot the moral and material preparation of the British Army for participation in large-scale warfare on the Continent for the first time since 1815. A study both of French and of German writings about continental warfare led such British military writers as Spenser Wilkinson and F. N. Maude straight back to Clausewitz. On War, which had first been translated in 1873, was republished in 1908 to the accompaniment of many laudatory commentaries. By 1914 the British military leadership was no less impregnated than its continental contemporaries with a belief in the supremacy of moral forces, the need to seek out the enemy's centre of gravity in his army and defeat it in a decisive battle, whatever the cost. Like their continental contemporaries they also believed that the battle, though bloody, would be brief; and when events proved them wrong they settled down to the grim slogging match that followed with all the calm determination that Clausewitz prescribed for his commanders, ignoring the siren songs of those who argued that there might be a less painful road to victory and supposed it possible ‘for a particularly (page 71)p. 71ingenious method of inflicting minor direct damage on the enemy's forces to lead to major indirect destruction’ (p. 228).

For this was precisely the claim made by critics of Britain's Western Front strategy, both at the time and since. Before 1914 the naval historian Julian Corbett had suggested that over the centuries the British had developed a ‘maritime strategy’ that was quite distinct from the Clausewitzian continental strategy. This consisted in using naval power both to bring direct economic pressure on a continental adversary, and to make limited military interventions on the Continent, as Wellington had done in the Peninsula during the Napoleonic Wars, with effects that could be out of all proportion to their size. This was the strategy advocated before the war by the naval authorities as against that of immediate and full-scale continental intervention favoured by the Army. It was rejected. But when at the end of 1914 the battles in the West ended in deadlock, it was revived and put into effect with the Dardanelles campaign, which was indeed seen by its authors as ‘a particularly ingenious method of inflicting minor direct damage on the enemy's forces [so as] to lead to major indirect destruction’.

The tactical failure at the Dardanelles makes it impossible to judge whether the ‘indirect’ strategy it was meant to serve would have produced the results expected of it. At all events, the cost imposed by the return to a ‘continental’ strategy for the remainder of the war left a general impression, which grew stronger with the passage of years, that there must have been a more humane and economical way of obtaining victory; an impression crystallized by the teaching of the writer B. H. Liddell Hart, whose writings on The Strategy of the Indirect Approach and The British Way in Warfare were both widely read and highly influential on the formulation of British policy in the 1930s. So whereas in the Soviet Union Clausewitz was elevated to the strategic pantheon and in Germany he remained a deeply revered figure (indeed in the Nazi era he was almost idolized), in Britain his teachings fell into a neglect from which they have only recently begun to recover.

(page 72)p. 72The major strategic innovation of the inter-war years was the development of air power. The theorists who pressed for its development used Clausewitzian arguments, but few mentioned his name. They started with his concept of ‘the centre of gravity’. The experience of the First World War, they argued, had shown that the centre of gravity of a belligerent power was no longer to be found in his armed forces. The vital factor was now the morale of his civilian population. It had been the disintegration of the Home Front, not the defeat of their armed forces, that had caused the collapse, first of Russia, then of the Central Powers. Air power now made it possible to attack this centre of gravity directly. So it was against this ‘hub of all power and movement, on which everything depends, that … all our energies should be directed’ (p. 596).

The refusal of the older services to accept this claim, and the controversies that ensued, added to the unprecedented complexity of the decisions that had to be taken by the Allies during the course of the Second World War. This was a conflict that lent itself at every level to Clausewitzian analysis. On every side, save in Japan, there was complete political control of strategic decisions. Clausewitz would have approved the efforts of Hitler in the early years to use his armed forces as instruments of his policy, but would have noted how the unlimited nature of his objectives made the war a total one far beyond his capacity to wage. He would have commented on the importance of public opinion in the formulation of Allied strategy, and might have indicated how the strength of this, once aroused, made virtually inevitable the policy of ‘unconditional surrender’ and very difficult any readjustment of Western policy to protect its interests against the Soviet Union during the last year of the war. Democratic governments are ill-adapted to carry out the fine tuning that characterized the age of Frederick the Great. He would have noted with interest the problems that confronted the Allies in determining the enemy ‘centre of gravity’, and the decision by the American High Command in 1941 that it lay, not with their immediate enemy, Japan, but with that enemy's stronger ally, Germany. (page 73)p. 73Above all, he would have found plenty of justification for his argument about the desirability of being very strong; first everywhere and then at the decisive point. It was ultimately by the deployment of an overwhelming superiority of force that the war was to be won.

The advent of nuclear weapons did not at first introduce any fundamental transformation of strategic thinking. During the Second World War the conflict between the exponents of air power and the more traditional strategists had been resolved by the surface forces being used to seize territory from which air attacks could be launched against both Germany and Japan in such strength that ultimately not only the will but the very capacity of those powers to resist had been shattered. Both land and naval power was necessary to enable air power to operate, and so it was in the first few years of the nuclear era. American nuclear weapons could be delivered against the Soviet Union only from vulnerable manned bombers whose bases, especially those in Western Europe, had to be protected against land attack. It was only the development of thermonuclear weapons with their almost inconceivable capacity for mass destruction, and then that of inter-continental ballistic missiles, that introduced an entirely new possibility into the conduct of war, making feasible the total destruction of the enemy's will to resist without first defeating his armed forces.

This meant that ‘absolute war’ as defined by Clausewitz was no longer a Platonic ideal but a physical possibility. War could now consist of ‘a single short blow’. In his prophetic words:

If war consisted of one decisive act, or a set of simultaneous decisions, preparations would tend towards totality, because no omission could ever be rectified. The sole criterion for preparations which the world of reality could provide would be the measures taken by the adversary, so far as they are known; the rest would once more be reduced to abstract calculations.

(p. 79)

(page 74)p. 74This is a depressingly accurate description of nuclear strategy as it developed during the ‘Cold War’ of 1949–89. Clausewitz had maintained that such a situation could never arise because ‘the very nature of the resources [available for war] and their employment means that they cannot all be deployed at the same moment. The resources in question are the fighting forces proper, the country with its physical features and population, and its allies.’ It was the deployment of this complex range of resources that made war such a protracted and unpredictable activity, creating that element of friction and uncertainty that kept all efforts short of the absolute.

Now all those internal constraints on ‘absolute war’ were removed and its complete realization had for the first time become a practical possibility; not, as Clausewitz had expected, through the unchaining of popular passions (although it was certainly this that made the two World Wars such ‘total wars’) but because of the factor that neither he nor any other serious thinker of his era had ever considered: technology. Whereas in Clausewitz's day human effort had been necessary to transcend the limitations imposed on the conduct of war by the constraints of the real world, now that effort was needed to impose such limits.

Clausewitz himself, it will be recalled, had identified two constraints on absolute war. One was the internal braking mechanism imposed by friction. The other was the external one imposed by the political aim – both the political circumstances out of which the war arose and the political conditions it was intended to bring about. In nuclear as in any other kind of war, therefore, Clausewitz's advice remains good. ‘No one starts a war – or rather, no one in his senses should do so – without first being clear in his mind what he intends to achieve by that war and how he intends to conduct it’ (p. 579).

The political aim, the object (Zweck) of the war, was thus even more significant than it had been in Clausewitz's day. But whereas Clausewitz (page 75)p. 75visualized the political object as something which, if sufficiently grandiose, would enable the commander to break through the barriers of human weakness that normally limited war; in the nuclear age the political object had to be kept in mind in order to impose limits on an activity whose destructiveness, left to itself, will rapidly escalate to extremes of a kind such as Clausewitz had never conceived.

This was the essence of the theory of nuclear deterrence. The assumption which underlies this theory is that no political object is sufficiently desirable to compensate for the nuclear devastation of one's homeland. It is thus possible to set on victory, in Clausewitz's words ‘an unacceptably high cost’ (p. 91). And here one should also note the relevance to the concept of nuclear deterrence of what Clausewitz had to say about unfought engagements being as significant in their effects as fought ones. Nuclear deterrence consists almost entirely in calculating the effects of unfought engagements. An effective deterrent posture thus imposes on one's adversary very stringent limitations on the political objectives that he is likely to seek to attain by military means, as well as on the means that he is likely to use in order to attain them.

Clausewitz's thinking was also relevant to the problems of nuclear war in another way. In any international conflict the immediate political object is likely to be the control of territory. Even if the fundamental causes are to be sought in ideological rivalries or fears for the balance of power, a territorial objective will almost certainly be adopted (as was Belgium by both Germany and Britain in the First World War) ‘that will serve the political purpose and symbolise it in the peace negotiations’ (p. 81). The war is thus likely to resolve itself into, even if it does not immediately arise out of, a struggle for the control of territory, whatever may be the broader implications that lie behind that struggle. So at once the traditional elements of territory and armed forces are reintroduced into strategic calculations, bringing back with them the twilit atmosphere of friction. And in that (page 76)p. 76environment all the considerations analysed by Clausewitz would be as relevant as they were a century and a half – or a millennium and a half – ago.

But control over territory involves also control over the people who live there, and here again the Clausewitzian insights have a lasting relevance. The essence of his teaching about popular participation in war is not to be found in the famous chapter on ‘The People in Arms’ – which is almost always misleadingly quoted out of its context – but in what he had to say about the long-term political processes that were making such participation inevitable, whether one liked it or not. Peoples were less and less likely to allow their political destinies to be determined over their heads. Mao Zedong and the theorists of revolutionary warfare gave to this social dimension an overriding importance which perhaps it deserves only in the context of ‘wars of national liberation’; but it is one that strategists under any circumstances ignore at their peril. In this respect Marxist military thinkers had a far more realistic grasp of the central issues than their opposite numbers, hypnotized as they were by technology and geopolitics, in the West. If the people themselves are not prepared if necessary to take part in the defence of their country, they cannot in the long run be protected; and if they are not prepared to acquiesce indefinitely in alien conquest, that conquest cannot in the long run be sustained.

So it is as well to conclude where Clausewitz did himself, with his depiction of war as a ‘remarkable trinity’

composed of primordial violence, hatred and enmity, which are to be regarded as a blind natural force; of the play of chance and probability within which the creative spirit is free to roam; and of its element of subordination as an instrument of policy, which makes it subject to reason alone. The first of these three aspects mainly concerns the people; the second the commander and his army; the third the government … (page 77)p. 77These three tendencies are like three different codes of law, deep-rooted in their subject and yet variable in their relationship to one another. A theory that ignores any one of them or seeks to fix an arbitrary relationship between them would conflict with reality to such an extent that for this reason alone it would be totally useless.

(p. 89; emphasis added)

Such was Clausewitz's conclusion. It would be a good place for any contemporary strategic thinker to begin.