On War

by Carl von Clausewitz

However small and weak a State may be in comparison to its enemy, if it foregoes a last supreme effort, we must say there is no longer any soul left in it. This does not exclude the possibility of saving itself from complete destruction by the purchase of peace at a sacrifice; but neither does such an aim on its part do away with the utility of fresh measures for defence; they will neither make peace more difficult nor more onerous, but easier and better. They are still more necessary if there is an expectation of assistance from those who are interested in maintaining our political existence. Any government, therefore, which, after the loss of a great battle, only thinks how it may speedily place the nation in the lap of peace, and unmanned by the feeling of great hopes disappointed, no longer feels in itself the courage or the desire to stimulate to the utmost every element of force, completely stultifies itself in such case through weakness, and shows itself unworthy of victory, and, perhaps, just on that account, was incapable of gaining one.

However decisive, therefore, the overthrow may be which is experienced by a State, still by a retreat of the army into the interior, the efficacy of its fortresses and an arming of the people may be brought into use. In connection with this it is advantageous if the flank of the principal theatre of war is fenced in by mountains, or otherwise very difficult tracts of country, which stand forth as bastions, the strategic enfilade of which is to check the enemy’s progress.

If the victorious enemy is engaged in siege works, if he has left strong garrisons behind him everywhere to secure his communications, or detached corps to make himself elbow-room, and to keep the adjacent provinces in subjection, if he is already weakened by his various losses in active means and material of war, then the moment is arrived when the defensive army should again enter the lists, and by a well-directed blow make the assailant stagger in his disadvantageous position.

CHAPTER XXVII.
Defence of a Theatre of War

Having treated of the most important defensive means, we might perhaps be contented to leave the manner in which these means attach themselves to the plan of defence as a whole to be discussed in the last Book, which will be devoted to the Plan of a War; for from this every secondary scheme, either of attack or defence, emanates and is determined in its leading features; and moreover in many cases the plan of the war itself is nothing more than the plan of the attack or defence of the principal theatre of war. But we have not been able to commence with war as a whole, although in war more than in any other phase of human activity, the parts are shaped by the whole, imbued with and essentially altered by its character; instead of that, we have been obliged to make ourselves thoroughly acquainted, in the first instance, with each single subject as a separate part. Without this progress from the simple to the complex, a number of undefined ideas would have overpowered us, and the manifold phases of reciprocal action in particular would have constantly confused our conceptions. We shall therefore still continue to advance towards the whole by one step at a time; that is, we shall consider the defence of a theatre in itself, and look for the thread by which the subjects already treated of connect themselves with it.

The defensive, according to our conception, is nothing but the stronger form of combat. The preservation of our own forces and the destruction of those of the enemy—in a word, the victory—is the aim of this contest, but at the same time not its ultimate object.

That object is the preservation of our own political state and the subjugation of that of the enemy; or again, in one word, the desired peace, because it is only by it that this conflict adjusts itself, and ends in a common result.

But what is the enemy’s state in connection with war? Above all things its military force is important, then its territory; but certainly there are also still many other things which, through particular circumstances, may obtain a predominant importance; to these belong, before all, foreign and domestic political relations, which sometimes decide more than all the rest. But although the military force and the territory of the enemy alone are still not the state itself, nor are they the only connections which the state may have with the war, still these two things are always preponderating, mostly immeasurably surpassing all other connections in importance. Military force is to protect the territory of the state, or to conquer that of an enemy; the territory on the other hand, constantly nourishes and renovates the military force. The two, therefore, depend on each other, mutually support each other, are equal in importance one to the other. But still there is a difference in their mutual relations. If the military force is destroyed, that is completely defeated, rendered incapable of further resistance, then the loss of the territory follows of itself; but on the other hand, the destruction of the military force by no means follows from the conquest of the country, because that force may of its own accord evacuate the territory, in order afterwards to reconquer it the more easily. Indeed, not only does the complete destruction of its army decide the fate of a country, but even every considerable weakening of its military force leads regularly to a loss of territory; on the other hand, every considerable loss of territory does not cause a proportionate diminution of military power; in the long run it will do so, but not always within the space of time in which a war is brought to a close.

From this it follows that the preservation of our own military power, and the diminution or destruction of that of the enemy, take precedence in importance over the occupation of territory, and, therefore, is the first object which a general should strive for. The possession of territory only presses for consideration as an object if that means (diminution or destruction of the enemy’s military force) has not effected it.

If the whole of the enemy’s military power was united in one army, and if the whole war consisted of one battle, then the possession of the country would depend on the issue of that battle; destruction of the enemy’s military forces, conquest of his country and security of our own, would follow from that result, and, in a certain measure, be identical with it. Now the question is, what can induce the defensive to deviate from this simplest form of the act of warfare, and distribute his power in space? The answer is, the insufficiency of the victory which he might gain with all his forces united. Every victory has its sphere of influence. If this extends over the whole of the enemy’s state, consequently over the whole of his military force and his territory, that is, if all the parts are carried along in the same movement, which we have impressed upon the core of his power, then such a victory is all that we require, and a division of our forces would not be justified by sufficient grounds. But if there are portions of the enemy’s military force, and of country belonging to either party, over which our victory would have no effect, then we must give particular attention to those parts; and as we cannot unite territory like a military force in one point, therefore we must divide our forces for the purpose of attacking or defending those portions.