the theory of war

the last thing that an explorer arrives at is a complete map that will cover the whole ground he has travelled, but for those who come after him and would profit by and extend his knowledge his map is the first thing with which they will begin. so it is with strategy. before we start upon its study we seek a chart which will show us at a glance what exactly is the ground we have to cover and what are the leading features which determine its form and general characteristics. such a chart a "theory of war" alone can provide. it is for this reason that in the study of war we must get our theory clear before we can venture in search of practical conclusions. so great is the complexity of war that without such a guide we are sure to go astray amidst the bewildering multiplicity of tracks and obstacles that meet us at every step. if for continental strategy its value has been proved abundantly, then for maritime strategy, where the conditions are far more complex, the need of it is even greater.

by maritime strategy we mean the principles which govern a war in which the sea is a substantial factor. naval strategy is but that part of it which determines the movements of the fleet when maritime strategy has determined what part the fleet must play in relation to the action of the land forces; for it scarcely needs saying that it is almost impossible that a war can be decided by naval action alone. unaided, naval pressure [pg 16] can only work by a process of exhaustion. its effects must always be slow, and so galling both to our own commercial community and to neutrals, that the tendency is always to accept terms of peace that are far from conclusive. for a firm decision a quicker and more drastic form of pressure is required. since men live upon the land and not upon the sea, great issues between nations at war have always been decided—except in the rarest cases—either by what your army can do against your enemy's territory and national life or else by the fear of what the fleet makes it possible for your army to do.

the paramount concern, then, of maritime strategy is to determine the mutual relations of your army and navy in a plan of war. when this is done, and not till then, naval strategy can begin to work out the manner in which the fleet can best discharge the function assigned to it.

the problem of such co-ordination is one that is susceptible of widely varying solutions. it may be that the command of the sea is of so urgent an importance that the army will have to devote itself to assisting the fleet in its special task before it can act directly against the enemy's territory and land forces; on the other hand, it may be that the immediate duty of the fleet will be to forward military action ashore before it is free to devote itself whole-heartedly to the destruction of the enemy's fleets. the crude maxims as to primary objects which seem to have served well enough in continental warfare have never worked so clearly where the sea enters seriously into a war. in such cases it will not suffice to say the primary object of the army is to destroy the enemy's army, or that of the fleet to destroy the enemy's fleet. the delicate interactions of the land and sea factors produce conditions too intricate for such blunt solutions. even the initial equations they present are too complex to be reduced by the simple application of rough-and-ready maxims. their right handling depends upon the broadest and most fundamental [pg 17] principles of war, and it is as a standpoint from which to get a clear and unobstructed view of the factors in their true relations that a theory of war has perhaps its highest value.

the theory which now holds the field is that war in a fundamental sense is a continuation of policy by other means. the process by which the continental strategists arrived at it involved some hard philosophical reasoning. practical and experienced veterans as they were, their method is not one that works easily with our own habit of thought. it will be well, therefore, to endeavour first to present their conclusions in a concrete form, which will make the pith of the matter intelligible at once. take, now, the ordinary case of a naval or military staff being asked to prepare a war plan against a certain state and to advise what means it will require. to any one who has considered such matters it is obvious the reply must be another question—what will the war be about? without a definite answer or alternative answers to that question a staff can scarcely do more than engage in making such forces as the country can afford as efficient as possible. before they take any sure step further they must know many things. they must know whether they are expected to take something from the enemy, or to prevent his taking something either from us or from some other state. if from some other state, the measures to be taken will depend on its geographical situation and on its relative strength by land and sea. even when the object is clear it will be necessary to know how much value the enemy attaches to it. is it one for which he will be likely to fight to the death, or one which he will abandon in the face of comparatively slight resistance? if the former, we cannot hope to succeed without entirely overthrowing his powers of resistance. if the latter, it [pg 18] will suffice, as it often has sufficed, to aim at something less costly and hazardous and better within our means. all these are questions which lie in the lap of ministers charged with the foreign policy of the country, and before the staff can proceed with a war plan they must be answered by ministers.

in short, the staff must ask of them what is the policy which your diplomacy is pursuing, and where, and why, do you expect it to break down and force you to take up arms? the staff has to carry on in fact when diplomacy has failed to achieve the object in view, and the method they will use will depend on the nature of that object. so we arrive crudely at our theory that war is a continuation of policy, a form of political intercourse in which we fight battles instead of writing notes.

it was this theory, simple and even meaningless as it appears at first sight, that gave the key to the practical work of framing a modern war plan and revolutionised the study of strategy. it was not till the beginning of the nineteenth century that such a theory was arrived at. for centuries men had written on the "art of war," but for want of a working theory their labours as a whole had been unscientific, concerned for the most part with the discussion of passing fashions and the elaboration of platitudes. much good work it is true was done on details, but no broad outlook had been obtained to enable us to determine their relation to the fundamental constants of the subject. no standpoint had been found from which we could readily detach such constants from what was merely accidental. the result was a tendency to argue too exclusively from the latest examples and to become entangled in erroneous thought by trying to apply the methods which had attained the last success to war as a [pg 19] whole. there was no means of determining how far the particular success was due to special conditions and how far it was due to factors common to all wars.

it was the revolutionary and napoleonic wars, coinciding as they did with a period of philosophic activity, that revealed the shallowness and empirical nature of all that had been done up to that time. napoleon's methods appeared to his contemporaries to have produced so strenuous a revolution in the conduct of land warfare that it assumed a wholly new aspect, and it was obvious that those conceptions which had sufficed previously had become inadequate as a basis of sound study. war on land seemed to have changed from a calculated affair of thrust and parry between standing armies to a headlong rush of one nation in arms upon another, each thirsting for the other's life, and resolved to have it or perish in the attempt. men felt themselves faced with a manifestation of human energy which had had no counterpart, at least in civilised times.

the assumption was not entirely true. for although the continent had never before adopted the methods in question, our own country was no stranger to them either on sea or land. as we shall see, our own revolution in the seventeenth century had produced strenuous methods of making war which were closely related to those which napoleon took over from the french revolutionary leaders. a more philosophic outlook might have suggested that the phenomenon was not really exceptional, but rather the natural outcome of popular energy inspired by a stirring political ideal. but the british precedent was forgotten, and so profound was the disturbance caused by the new french methods that its effects [pg 20] are with us still. we are in fact still dominated by the idea that since the napoleonic era war has been essentially a different thing. our teachers incline to insist that there is now only one way of making war, and that is napoleon's way. ignoring the fact that he failed in the end, they brand as heresy the bare suggestion that there may be other ways, and not content with assuming that his system will fit all land wars, however much their natures and objects may differ, they would force naval warfare into the same uniform under the impression apparently that they are thereby making it presentable and giving it some new force.

seeing how cramping the napoleonic idea has become, it will be convenient before going further to determine its special characteristics exactly, but that is no easy matter. the moment we approach it in a critical spirit, it begins to grow nebulous and very difficult to define. we can dimly make out four distinct ideas mingled in the current notion. first, there is the idea of making war not merely with a professional standing army, but with the whole armed nation—a conception which of course was not really napoleon's. it was inherited by him from the revolution, but was in fact far older. it was but a revival of the universal practice which obtained in the barbaric stages of social development, and which every civilisation in turn had abandoned as economically unsound and subversive of specialisation in citizenship. the results of the abandonment were sometimes good and sometimes bad, but the determining conditions have been studied as yet too imperfectly to justify any broad generalisation. secondly, there is the idea of strenuous and persistent effort—not resting to secure each minor advantage, but pressing the enemy without pause or rest till he is utterly overthrown—an idea in which cromwell had anticipated napoleon by a century and [pg 21] a half. scarcely distinguishable from this is a third idea—that of taking the offensive, in which there was really nothing new at all, since its advantages had always been understood, and frederick the great had pressed it to extremity with little less daring than napoleon himself—nay even to culpable rashness, as the highest exponents of the napoleonic idea admit. finally, there is the notion of making the armed forces of the enemy and not his territory or any part of it your main objective. this perhaps is regarded as the strongest characteristic of napoleon's methods, and yet even here we are confused by the fact that undoubtedly on some very important occasions—the austerlitz campaign, for example—napoleon made the hostile capital his objective as though he believed its occupation was the most effective step towards the overthrow of the enemy's power and will to resist. he certainly did not make the enemy's main army his primary objective—for their main army was not mack's but that of the archduke charles.

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on the whole then, when men speak of the napoleonic system they seem to include two groups of ideas—one which comprises the conception of war made with the whole force of the nation; the other, a group which includes the cromwellian idea of persistent effort, frederick's preference for the offensive at almost any risk, and finally the idea of the enemy's armed forces as the main objective, which was also cromwell's.

it is the combination of these by no means original or very distinct ideas that we are told has brought about so entire a change in the conduct of war that it has become altogether a different thing. it is unnecessary for our purpose to consider how far the facts seem to support such a conclusion, for in the inherent nature of things it must be radically unsound. neither war nor anything else can change in its essentials. if it appears to do so, it is because we are still mistaking accidents for essentials, and this is exactly how it struck the acutest thinkers of napoleonic times.

for a while it is true they were bewildered, but so soon as they had had time to clear their heads from the din of the struggle in which they had taken part, they began to see that the new phenomena were but accidents after all. they perceived that napoleon's methods, which had taken the world by storm, had met with success in wars of a certain nature only, and that when he tried to extend those methods to other natures of war he had met with failure and even disaster. how was this to be explained? what theory, for instance, would cover napoleon's successes in germany and italy, as well as his failures in spain and russia? if the whole conception of war had changed, how could you account for the success of england, who had not changed her methods? to us the answer to these questions is of living and infinite importance. our standpoint remains still unchanged. is there anything inherent in the conception of war that justifies that attitude in our case? are we entitled to expect from it again the same success it met with in the past?

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the first man to enunciate a theory which would explain the phenomena of the napoleonic era and co-ordinate them with previous history was general carl von clausewitz, a man whose arduous service on the staff and the actual work of higher instruction had taught the necessity of systematising the study of his profession. he was no mere professor, but a soldier bred in the severest school of war. the pupil and friend of sharnhorst and gneisenau, he had served on the staff of blücher in 1813, he had been chief of the staff to wallmoden in his campaign against davoust on the lower elbe, and also to the third prussian army corps in [pg 24] the campaign of 1815. thereafter for more than ten years he was director of the general academy of war at berlin, and died in 1831 as chief of the staff to marshal gneisenau. for the fifty years that followed his death his theories and system were, as he expected they would be, attacked from all sides. yet to-day his work is more firmly established than ever as the necessary basis of all strategical thought, and above all in the "blood and iron" school of germany.

the process by which he reached his famous theory can be followed in his classical work on war and the notes regarding it which he left behind him. in accordance with the philosophic fashion of his time he began by trying to formulate an abstract idea of war. the definition he started with was that "war is an act of violence to compel our opponent to do our will." but that act of violence was not merely "the shock of armies," as montecuccoli had defined it a century and a half before. if the abstract idea of war be followed to its logical conclusion, the act of violence must be performed with the whole of the means at our disposal and with the utmost exertion of our will. consequently we get the conception of two armed nations flinging themselves one upon the other, and continuing the struggle with the utmost strength [pg 25] and energy they can command till one or other is no longer capable of resistance. this clausewitz called "absolute war." but his practical experience and ripe study of history told him at once that "real war" was something radically different. it was true, as he said, that napoleon's methods had approximated to the absolute and had given some colour to the use of the absolute idea as a working theory. "but shall we," he acutely asks, "rest satisfied with this idea and judge all wars by it however much they may differ from it—shall we deduce from it all the requirements of theory? we must decide the point, for we can say nothing trustworthy about a war plan until we have made up our minds whether war should only be of this kind or whether it may be of another kind." he saw at once that a theory formed upon the abstract or absolute idea of war would not cover the ground, and therefore failed to give what was required for practical purposes. it would exclude almost the whole of war from alexander's time to napoleon's. and what guarantee was there that the next war would confirm to the napoleonic type and accommodate itself to the abstract theory? "this theory," he says, "is still quite powerless against the force of circumstances." and so it proved, for the wars of the middle nineteenth century did in fact revert to the pre-napoleonic type.

in short, clausewitz's difficulty in adopting his abstract theory as a working rule was that his practical mind could not forget that war had not begun with the revolutionary era, nor was it likely to end with it. if that era had changed [pg 26] the conduct of war, it must be presumed that war would change again with other times and other conditions. a theory of war which did not allow for this and did not cover all that had gone before was no theory at all. if a theory of war was to be of any use as a practical guide it must cover and explain not only the extreme manifestation of hostility which he himself had witnessed, but every manifestation that had occurred in the past or was likely to recur in the future.

it was in casting about for the underlying causes of the oscillations manifested in the energy and intensity of hostile relations that he found his solution. his experience on the staff, and his study of the inner springs of war, told him it was never in fact a question of purely military endeavour aiming always at the extreme of what was possible or expedient from a purely military point of view. the energy exhibited would always be modified by political considerations and by the depth of the national interest in the object of the war. he saw that real war was in fact an international relation which differed from other international relations only in the method we adopted to achieve the object of our policy. so it was he arrived at his famous theory—"that war is a mere continuation of policy by other means."

at first sight there seems little enough in it. it may seem perhaps that we have been watching a mountain in labour and nothing but a mouse has been produced. but it is only upon some such simple, even obvious, formula that any scientific system can be constructed with safety. we have only to develop the meaning of this one to see how important and practical are the guiding lines which flow from it.

with the conception of war as a continuation of political intercourse before us, it is clear that everything which lies outside the political conception, everything, that is, which is [pg 27] strictly peculiar to military and naval operations, relates merely to the means which we use to achieve our policy. consequently, the first desideratum of a war plan is that the means adopted must conflict as little as possible with the political conditions from which the war springs. in practice, of course, as in all human relations, there will be a compromise between the means and the end, between the political and the military exigencies. but clausewitz held that policy must always be the master. the officer charged with the conduct of the war may of course demand that the tendencies and views of policy shall not be incompatible with the military means which are placed at his disposal; but however strongly this demand may react on policy in particular cases, military action must still be regarded only as a manifestation of policy. it must never supersede policy. the policy is always the object; war is only the means by which we obtain the object, and the means must always keep the end in view.

the practical importance of this conception will now become clear. it will be seen to afford the logical or theoretical exposition of what we began by stating in its purely concrete form. when a chief of staff is asked for a war plan he must not say we will make war in such and such a way because it was napoleon's or moltke's way. he will ask what is the political object of the war, what are the political conditions, and how much does the question at issue mean respectively to us and to our adversary. it is these considerations which determine the nature of the war. this primordial question settled, he will be in a position to say whether the war is of the same nature as those in which napoleon's and moltke's methods were successful, or whether it is of another nature in which those methods failed. he will then design and offer a [pg 28] war plan, not because it has the hall-mark of this or that great master of war, but because it is one that has been proved to fit the kind of war in hand. to assume that one method of conducting war will suit all kinds of war is to fall a victim to abstract theory, and not to be a prophet of reality, as the narrowest disciples of the napoleonic school are inclined to see themselves.

hence, says clausewitz, the first, the greatest and most critical decision upon which the statesman and the general have to exercise their judgment is to determine the nature of the war, to be sure they do not mistake it for something nor seek to make of it something which from its inherent conditions it can never be. "this," he declares, "is the first and the most far-reaching of all strategical questions."

the first value, then, of his theory of war is that it gives a clear line on which we may proceed to determine the nature of a war in which we are about to engage, and to ensure that we do not try to apply to one nature of war any particular course of operations simply because they have proved successful in another nature of war. it is only, he insists, by regarding war not as an independent thing but as a political instrument that we can read aright the lessons of history and understand for our practical guidance how wars must differ in character according to the nature of the motives and circumstances from which they proceed. this conception, he claims, is the first ray of light to guide us to a true theory of war and thereby enable us to classify wars and distinguish them one from another.

jomini, his great contemporary and rival, though proceeding by a less philosophical but no less lucid method, entirely endorses this view. a swiss soldier of fortune, his [pg 29] experience was much the same as that of clausewitz. it was obtained mainly on the staff of marshal ney and subsequently on the russian headquarter staff. he reached no definite theory of war, but his fundamental conclusions were the same. the first chapter of his final work, précis de l'art de la guerre, is devoted to "la politique de la guerre." in it he classifies wars into nine categories according to their political object, and he lays it down as a base proposition "that these [pg 30] different kinds of war will have more or less influence on the nature of the operations which will be demanded to attain the end in view, on the amount of energy that must be put forth, and on the extent of the undertakings in which we must engage." "there will," he adds, "be a great difference in the operations according to the risks we have to run."

both men, therefore, though on details of means they were often widely opposed, are agreed that the fundamental conception of war is political. both of course agree that if we isolate in our mind the forces engaged in any theatre of war the abstract conception reappears. so far as those forces are concerned, war is a question of fighting in which each belligerent should endeavour by all means at his command and with all his energy to destroy the other. but even so they may find that certain means are barred to them for political reasons, and at any moment the fortune of war or a development of the political conditions with which it is entangled may throw them back upon the fundamental political theory.

that theory it will be unprofitable to labour further at this point. let it suffice for the present to mark that it gives us a conception of war as an exertion of violence to secure a political end which we desire to attain, and that from this broad and simple formula we are able to deduce at once that wars will vary according to the nature of the end and the intensity of our desire to attain it. here we may leave it to gather force and coherence as we examine the practical considerations which are its immediate outcome.