When he conceived the idea, the only kind of limited object he had in his mind was, to use his own words, "some conquests on the frontiers of the enemy's country," such as Silesia and Saxony for Frederick the Great, Belgium in his own war plan, and Alsace-Lorraine in that of Moltke. Now it is obvious that such objects are not truly limited, for two reasons. In the first place, such territory is usually an organic part of your enemy's country, or otherwise of so much importance to him that he will be willing to use unlimited effort to retain it. In the second place, there will be no strategical obstacle to his being able to use his whole force to that end. To satisfy the full conception of a limited object, one of two conditions is essential. Firstly, it must be not merely limited in area, but of really limited political importance; and secondly, it must be so situated as to be strategically isolated or to be capable of being reduced to practical isolation by strategical operations. Unless this condition exists, it is in the power of either belligerent, as Clausewitz himself saw, to pass to unlimited war if he so desires, and, ignoring the territorial objective, to strike at the heart of his enemy and force him to desist.
If, then, we only regard war between contiguous continental States, in which the object is the conquest of territory on either of their frontiers, we get no real generic difference between limited and unlimited war. The line between them is in any case too shadowy or unstable to give a classification of any solidity. It is a difference of degree rather than of kind. If, on the other hand, we extend our view to wars between worldwide empires, the distinction at once becomes organic. Possessions which lie oversea or at the extremities of vast areas of imperfectly settled territory are in an entirely different category from those limited objects which Clausewitz contemplated. History shows that they can never have the political importance of objects which are organically part of the European system, and it shows further that they can be isolated by naval action sufficiently to set up the conditions of true limited war.
Jomini approaches the point, but without clearly detaching it. In his chapter "On Great Invasions and Distant Expeditions," he points out how unsafe it is to take the conditions of war between contiguous States and apply them crudely to cases where the belligerents are separated by large areas of land or sea. He hovers round the sea factor, feeling how great a difference it makes, but without getting close to the real distinction. His conception of the inter-action of fleets and armies never rises above their actual co-operation in touch one with the other in a distant theatre. He has in mind the assistance which the British fleet afforded Wellington in the Peninsula, and Napoleon's dreams of Asiatic conquest, pronouncing such distant invasions as impossible in modern times except perhaps in combination with a powerful fleet that could provide the army of invasion with successive advanced bases. Of the paramount value of the fleet's isolating and preventive functions he gives no hint.
Even when he deals with oversea expeditions, as he does at some length, his grip of the point is no closer. It is indeed significant of how entirely continental thought had failed to penetrate the subject that in devoting over thirty pages to an enumeration of the principles of oversea expeditions, he, like Clausewitz, does not so much as mention the conquest of Canada; and yet it is the leading case of a weak military Power succeeding by the use of the limited form of war in forcing its will upon a strong one, and succeeding because it was able by naval action to secure its home defence and isolate the territorial object.
For our ideas of true limited objects, therefore, we must leave the continental theatres and turn to mixed or maritime wars. We have to look to such cases as Canada and Havana in the Seven Years' War, and Cuba in the Spanish-American War, cases in which complete isolation of the object by naval action was possible, or to such examples as the Crimea and Korea, where sufficient isolation was attainable by naval action owing to the length and difficulty of the enemy's land communications and to the strategical situation of the territory at stake.
These examples will also serve to illustrate and enforce the second essential of this kind of war. As has been already said, for a true limited object we must have not only the power of isolation, but also the power by a secure home defence of barring an unlimited counterstroke. In all the above cases this condition existed. In all of them the belligerents had no contiguous frontiers, and this point is vital. For it is obvious that if two belligerents have a common frontier, it is open to the superior of them, no matter how distant or how easy to isolate the limited object may be, to pass at will to unlimited war by invasion. This process is even possible when the belligerents are separated by a neutral State, since the territory of a weak neutral will be violated if the object be of sufficient importance, or if the neutral be too strong to coerce, there still remains the possibility that his alliance may be secured.
We come, then, to this final propositionthat limited war is only permanently possible to island Powers or between Powers which are separated by sea, and then only when the Power desiring limited war is able to command the sea to such a degree as to be able not only to isolate the distant object, but also to render impossible the invasion of his home territory.
Here, then, we reach the true meaning and highest military value of what we call the command of the sea, and here we touch the secret of England's success against Powers so greatly superior to herself in military strength. It is only fitting that such a secret should have been first penetrated by an Englishman. For so it was, though it must be said that except in the light of Clausewitz's doctrine the full meaning of Bacon's famous aphorism is not revealed. "This much is certain," said the great Elizabethan on the experience of our first imperial war; "he that commands the sea is at great liberty and may take as much or as little of the war as he will, whereas those that be strongest by land are many times nevertheless in great straits." It would be difficult to state more pithily the ultimate significance of Clausewitz's doctrine. Its cardinal truth is clearly indicatedthat limited wars do not turn upon the armed strength of the belligerents, but upon the amount of that strength which they are able or willing to bring to bear at the decisive point.
It is much to be regretted that Clausewitz did not live to see with Bacon's eyes and to work out the full comprehensiveness of his doctrine. His ambition was to formulate a theory which would explain all wars. He believed he had done so, and yet it is clear he never knew how complete was his success, nor how wide was the field he had covered. To the end it would seem he was unaware that he had found an explanation of one of the most inscrutable problems in historythe expansion of Englandat least so far as it has been due to successful war. That a small country with a weak army should have been able to gather to herself the most desirable regions of the earth, and to gather them at the expense of the greatest military Powers, is a paradox to which such Powers find it hard to be reconciled. The phenomenon seemed always a matter of chance-an accident without any foundation in the essential constants of war. It remained for Clausewitz, unknown to himself, to discover that explanation, and he reveals it to us in the inherent strength of limited war when means and conditions are favourable for its use.
We find, then, if we take a wider view than was open to Clausewitz and submit his latest ideas to the test of present imperial conditions, so far from failing to cover the ground they gain a fuller meaning and a firmer basis. Apply them to maritime warfare and it becomes clear that his distinction between limited and unlimited war does not rest alone on the moral factor. A war may be limited not only because the importance of the object is too limited to call forth the whole national force, but also because the sea may be made to present an insuperable physical obstacle to the whole national force being brought to bear. That is to say, a war may be limited physically by the strategical isolation of the object, as well as morally by its comparative unimportance.
We find, then, if we take a wider view than was open to Clausewitz and submit his latest ideas to the test of present imperial conditions, so far from failing to cover the ground they gain a fuller meaning and a firmer basis. Apply them to maritime warfare and it becomes clear that his distinction between limited and unlimited war does not rest alone on the moral factor. A war may be limited not only because the importance of the object is too limited to call forth the whole national force, but also because the sea may be made to present an insuperable physical obstacle to the whole national force being brought to bear. That is to say, a war may be limited physically by the strategical isolation of the object, as well as morally by its comparative unimportance.
CHAPTER FIVE
WARS OF INTERVENTIONLIMITED INTERFERENCE IN UNLIMITED WAR
Before leaving the general consideration of limited war, we have still to deal with a form of it that has not yet been mentioned. Clausewitz gave it provisionally the name of "War limited by contingent," and could find no place for it in his system. It appeared to him to differ essentially from war limited by its political object, or as Jomini put it, war with a territorial object. Yet it had to be taken into account and explained, if only for the part it had played in European history.
For us it calls for the most careful examination, not only because it baffled the great German strategist to reconcile it with his theory of war, but also because it is the form in which Great Britain most successfully demonstrated the potentiality for direct continental interference of a small army acting in conjunction with a dominant fleet.
The combined operations which were the normal expression of the British method of making war on the limited basis were of two main classes. Firstly, there were those designed purely for the conquest of the objects for which we went to war, which were usually colonial or distant oversea territory; and secondly, operations more or less upon the European seaboard designed not for permanent conquest, but as a method of disturbing our enemy's plans and strengthening the hands of our allies and our own position. Such operations might take the form of insignificant coastal diversions, or they might rise through all degrees of importance till, as in Wellington's operations in the Peninsula, they became indistinguishable in form from regular continental warfare.
It would seem, therefore, that these operations were distinguished not so much by the nature of the object as by the fact that we devoted to them, not the whole of our military strength, but only a certain part of it which was known as our "disposal force." Consequently, they appear to call for some such special classification, and to fall naturally into the category which Clausewitz called "War limited by contingent."
It was a nature of war well enough known in another form on the Continent. During the eighteenth century there had been a large number of cases of war actually limited by contingentthat is, cases where a country not having a vital interest in the object made war by furnishing the chief belligerent with an auxiliary force of a stipulated strength.
It was in the sixth chapter of his last book that Clausewitz intended to deal with this anomalous form of hostility. His untimely death, however, has left us with no more than a fragment, in which he confesses that such cases are "embarrassing to his theory." If, he adds, the auxiliary force were placed unreservedly at the disposal of the chief belligerent, the problem would be simple enough. It would then, in effect, be the same thing as unlimited war with the aid of a subsidised force. But in fact, as he observes, this seldom happened, for the contingent was always more or less controlled in accordance with the special political aims of the Government which furnished it. Consequently, the only conclusion he succeeded in reaching was that it was a form of war that had to be taken into account, and that it was a form of limited war that appeared to differ essentially from war limited by object. We are left, in fact, with an impression that there must be two kinds of limited war.
But if we pursue his historical method and examine the cases in which this nature of war was successful, and those in which it was unsuccessful, we shall find that wherever success is taken as an index of its legitimate employment, the practical distinction between the two kinds of limited war tends to disappear. The indications are that where the essential factors which justify the use of war limited by object are present in war limited by contingent, then that form of war tends to succeed, but not otherwise. We are brought, in fact, to this proposition, that the distinction "Limited by contingent" is not one that is inherent in war, and is quite out of line with the theory in handthat, in reality, it is not a form of war, but a method which may be employed either for limited or unlimited war. In other words, war limited by contingent, if it is to be regarded as a legitimate form of war at all, must take frankly the one shape or the other. Either the contingent must act as an organic unit of the force making unlimited war without any reservations whatever, or else it should be given a definite territorial object, with an independent organisation and an independent limited function.
Our own experience seems to indicate that war by contingent or war with "a disposal force" attains the highest success when it approaches most closely to true limited warthat is, as in the case of the Peninsula and the Crimea, where its object is to wrest or secure from the enemy a definite piece of territory that to a greater or less extent can be isolated by naval action. Its operative power, in fact, appears to bear some direct relation to the intimacy with which naval and military action can be combined to give the contingent a weight and mobility that are beyond its intrinsic power.
If, then, we would unravel the difficulties of war limited by contingent, it seems necessary to distinguish between the continental and the British form of it. The continental form, as we have seen, differs but little in conception from unlimited war. The contingent is furnished at least ostensibly with the idea that it is to be used by the chief belligerent to assist him in overthrowing the common enemy, and that its objective will be the enemy's organised forces or his capital. Or it may be that the contingent is to be used as an army of observation to prevent a counterstroke, so as to facilitate and secure the main offensive movement of the chief belligerent. In either case, however small may be our contribution to the allied force, we are using the unlimited form and aiming at an unlimited and not a mere territorial object.
If now we turn to British experience of war limited by contingent, we find that the continental form has frequently been used, but we also find it almost invariably accompanied by a popular repugnance, as though there were something in it antagonistic to the national instinct. A leading case is the assistance we sent to Frederick the Great in the Seven Years' War. At the opening of the war, so great was the popular repugnance that the measure was found impossible, and it was not till Frederick's dazzling resistance to the Catholic powers had clothed him with the glory of a Protestant hero, that Pitt could do what he wanted. The old religious fire was stirred. The most potent of all national instincts kindled the people to a generous warmth which overcame their inborn antipathy to continental operations, and it was possible to send a substantial contingent to Frederick's assistance. In the end the support fully achieved its purpose, but it must be noted that even in this case the operations were limited not only by contingent but also by object. It is true that Frederick was engaged in an unlimited war in which the continued existence of Prussia was at stake, and that the British force was an organic element in his war plan. Nevertheless, it formed part of a British subsidised army under Prince Ferdinand of Brunswick, who though nominated by Frederick was a British commander-in-chief. His army was in organisation entirely distinct from that of Frederick, and it was assigned the very definite and limited function of preventing the French occupying Hanover and so turning the Prussian right flank. Finally it must be noted that its ability to perform this function was due to the fact that the theatre of operations assigned to it was such that in no probable event could it lose touch with the sea, nor could the enemy cut its lines of supply and retreat.