On War

by Carl von Clausewitz

We therefore maintain, that at each new stage of the defensive the preponderance, or more correctly speaking, the counterpoise increases in favour of the defensive, and consequently there is also a gain in power for the counterstroke.

Now are these advantages of the increasing force of the defensive to be had for nothing? By no means, for the sacrifice with which they are purchased increases in the same proportion.

If we wait for the enemy within our own theatre of war, however near the border of our territory the decision takes place, still this theatre of war is entered by the enemy, which must entail a sacrifice on our part; whereas, had we made the attack, this disadvantage would have fallen on the enemy. If we do not proceed at once to meet the enemy and attack him, our loss will be the greater, and the extent of the country which the enemy will overrun, as well as the time which he requires to reach our position, will continually increase. If we wish to give battle on the defensive, and we therefore leave its determination and the choice of time for it to the enemy, then perhaps he may remain for some time in occupation of the territory which he has taken, and the time which through his deferred decision we are allowed to gain will in that manner be paid for by us. The sacrifices which must be made become still more burdensome if a retreat into the heart of the country takes place.

But all these sacrifices on the part of the defensive, at most only occasion him in general a loss of power which merely diminishes his military force indirectly, therefore, at a later period, and not directly, and often so indirectly that its effect is hardly felt at all. The defensive, therefore, strengthens himself for the present moment at the expense of the future, that is to say, he borrows, as every one must who is too poor for the circumstances in which he is placed.

Now, if we would examine the result of these different forms of resistance, we must look to the object of the aggression. This is, to obtain possession of our theatre of war, or, at least, of an important part of it, for under the conception of the whole, at least the greater part must be understood, as the possession of a strip of territory few miles in extent is, as a rule, of no real consequence in strategy. As long, therefore, as the aggressor is not in possession of this, that is, as long as from fear of our force he has either not yet advanced to the attack of the theatre of war, or has not sought to find us in our position, or has declined the combat we offer, the object of the defence is fulfilled, and the effects of the measures taken for the defensive have therefore been successful. At the same time this result is only a negative one, which certainly cannot directly give the force for a real counterstroke. But it may give it indirectly, that is to say, it is on the way to do so; for the time which elapses the aggression loses, and every loss of time is a disadvantage, and must weaken in some way the party who suffers the loss.

Therefore in the first three stages of the defensive, that is, if it takes place on the frontier, the non-decision is already a result in favour of the defensive.

But it is not so with the fourth.

If the enemy lays siege to our fortresses we must relieve them in time, to do this we must therefore bring about the decision by positive action.

This is likewise the case if the enemy follows us into the interior of the country without besieging any of our places. Certainly in this case we have more time; we can wait until the enemy’s weakness is extreme, but still it is always an indispensable condition that we are at last to act. The enemy is now, perhaps, in possession of the whole territory which was the object of his aggression, but it is only lent to him; the tension continues, and the decision is yet pending. As long as the defensive is gaining strength and the aggressor daily becoming weaker, the postponement of the decision is in the interest of the former: but as soon as the culminating point of this progressive advantage has arrived, as it must do, were it only by the ultimate influence of the general loss to which the offensive has exposed himself, it is time for the defender to proceed to action, and bring on a solution, and the advantage of the “waiting for” may be considered as completely exhausted.

There can naturally be no point of time fixed generally at which this happens, for it is determined by a multitude of circumstances and relations; but it may be observed that the winter is usually a natural turning point. If we cannot prevent the enemy from wintering in the territory which he has seized, then, as a rule, it must be looked upon as given up. We have only, however, to call to mind Torres Vedras, to see that this is no general rule.