On War

by Carl von Clausewitz

b, when it is a principal object to gain time.

c, when there are peculiarities in the country which are favourable to the measure, a subject on which we have already treated in the twenty-fifth chapter.

We thus close the chapter on the defence of a theatre of war if a decisive solution is sought for by one or other party, and is therefore inevitable. But it must be particularly borne in mind, that events in war do not exhibit themselves in such a pure abstract form, and that therefore, if our maxims and arguments should be used in reasoning on actual war, our thirtieth chapter should also be kept in view, and we must suppose the general, in the majority of cases, as placed between two tendencies, urged more towards one or the other, according to circumstances.

CHAPTER XXIX.
Defence of a Theatre of War (continued)
Successive Resistance.

We have proved, in the twelfth and thirteenth chapters, that in strategy a successive resistance is inconsistent with the nature of the thing, and that all forces available should be used simultaneously.

As regards forces which are moveable, this requires no further demonstration; but when we look at the seat of war itself, with its fortresses, the natural divisions of the ground, and even the extent of its surface as being also elements of war, then, these being immovable, we can only either bring them gradually into use, or we must at once place ourselves so far back, that all agencies of this kind which are to be brought into activity are in our front. Then everything which can contribute to weaken the enemy in the territory which he has occupied, comes at once into activity, for the assailant must at least blockade the defender’s fortresses, he must keep the country in subjection by garrisons and other posts, he has long marches to make, and everything he requires must be brought from a distance, etc. All these agencies commence to work, whether the assailant makes his advance before or after a decision, but in the former case their influence is somewhat greater. From this, therefore, it follows, that if the defender chooses to transfer his decision to a point further back, he has thus the means of bringing at once into play all these immovable elements of military force.

On the other hand, it is clear that this transfer of the solution (on the part of the defender) does not alter the extent of the influence of a victory which the assailant gains. In treating of the attack, we shall examine more closely the extent of the influence of a victory; here we shall only observe that it reaches to the exhaustion of the superiority, that is, the resultant of the physical and moral relations. Now this superiority exhausts itself in the first place by the duties required from the forces on the theatre of war, and secondly by losses in combats; the diminution of force arising from these two causes cannot be essentially altered, whether the combats take place at the commencement or at the end, near the frontier, or further towards the interior of the country (vom oder hinten). We think, for example, that a victory gained by Buonaparte over the Russians at Wilna, 1812, would have carried him just as far as that of Borodino—assuming that it was equally great—and that a victory at Moscow would not have carried him any further; Moscow was, in either case, the limit of this sphere of victory. Indeed, it cannot be doubted for a moment that a decisive battle on the frontier (for other reasons) would have produced much greater results through victory, and then, perhaps, the sphere of its influence would have been wider. Therefore, in this view, also, the transfer of the decision to a point further back is not necessary for the defence.

In the chapter on the various means of resistance, that method of delaying the decision, which may be regarded as an extreme form, was brought before us under the name of retreat into the interior, and as a particular method of defence, in which the object is rather that the assailant should wear himself out, than that he should be destroyed by the sword on the field of battle. But it is only when such an intention predominates that the delaying of the decisive battle can be regarded as a peculiar method of resistance; for otherwise it is evident that an infinite number of gradations may be conceived in this method, and that these may be combined with all other means of defence. We therefore look upon the greater or less co-operation of the theatre of war, not as a special form of defence, but as nothing more than a discretionary introduction into the defence of the immovable means of resistance, just according as circumstances and the nature of the situation may appear to require.

But now, if the defender does not think he requires any assistance from these immovable forces for his purposed decision, or if the further sacrifice connected with the use of them is too great, then they are kept in reserve for the future, and form a sort of succession of reinforcements, which perhaps ensure the possibility of keeping the moveable forces in such a condition that they will be able to follow up the first favourable decision with a second, or perhaps in the same manner even with a third, that is to say, in this manner a successive application of his forces becomes possible.

If the defender loses a battle on the frontier, which does not amount to a complete defeat, we may very well imagine that, by placing himself behind the nearest fortress, he will then be in a condition to accept battle again; indeed, if he is only dealing with an opponent who has not much resolution, then, perhaps, some considerable obstacle of ground will be quite sufficient as a means of stopping the enemy.