On War

by Carl von Clausewitz

Now how can we conceive this waiting until the last moment, as well as this resistance, without such a corps being in constant danger of serious loss? Chiefly in this way, that the enemy himself is preceded by an advanced guard, and therefore does not advance at once with all the outflanking and overpowering weight of his whole force. Now, if this advance guard is also from the commencement superior to our advanced corps, as we may naturally suppose it is intended it should be, and if the enemy’s main body is also nearer to his advanced guard than we are to ours, and if that main body, being already on the march, will soon be on the spot to support the attack of his advanced guard with all his strength, still this first act, in which our advanced corps has to contend with the enemy’s advanced guard, that is with a force not much exceeding its own, ensures at once a certain gain of time, and thus allows of our watching the adversary’s movements for some time without endangering our own retreat.

But even a certain amount of resistance which such a corps can offer in a suitable position is not attended with such disadvantage as we might anticipate in other cases through the disproportion in the strength of the forces engaged. The chief danger in a contest with a superior enemy consists always in the possibility of being turned and placed in a critical situation by the enemy enveloping our position; but in the case to which our attention is now directed, a risk of this description is very much less, owing to the advancing enemy never knowing exactly how near there may be support from the main body of his opponent’s army itself, which may place his advanced column between two fires. The consequence is, that the enemy in advancing keeps the heads of his single columns as nearly as possible in line, and only begins very cautiously to attempt to turn one or other wing after he has sufficiently reconnoitred our position. While the enemy is thus feeling about and moving guardedly, the corps we have thrown forward has time to fall back before it is in any serious danger.

As for the length of the resistance which such a corps should offer against the attack in front, or against the commencement of any turning movement, that depends chiefly on the nature of the ground and the proximity of the enemy’s supports. If this resistance is continued beyond its natural measure, either from want of judgment or from a sacrifice being necessary in order to give the main body the time it requires, the consequence must always be a very considerable loss.

It is only in rare instances, and more especially when some local obstacle is favourable, that the resistance actually made in such a combat can be of importance, and the duration of the little battle of such a corps would in itself be hardly sufficient to gain the time required; that time is really gained in a threefold manner, which lies in the nature of the thing, viz.:

1. By the more cautious, and consequently slower advance of the enemy.

2. By the duration of the actual resistance offered.

3. By the retreat itself.

This retreat must be made as slowly as is consistent with safety. If the country affords good positions they should be made use of, as that obliges the enemy to organise fresh attacks and plans for turning movements, and by that means more time is gained. Perhaps in a new position a real combat even may again be fought.

We see that the opposition to the enemy’s progress by actual fighting and the retreat are completely combined with one another, and that the shortness of the duration of the fights must be made up for by their frequent repetition.

This is the kind of resistance which an advanced corps should offer. The degree of effect depends chiefly on the strength of the corps, and the configuration of the country; next on the length of the road which the corps has to march over, and the support which it receives.