On War

by Carl von Clausewitz

2. The advance is in the same manner more tedious in proportion as the masses increase, consequently, the time is longer before the career of aggression is run out, and the sum total of the daily losses is greater.

Three thousand men driving two thousand before them in an ordinary country, will not allow them to march at the rate of 1, 2, or at most 3 miles a day, and from time to time to make a few days’ halt. To come up with them, to attack them, and force them to make a further retreat is the work of a few hours; but if we multiply these masses by 100, the case is altered. Operations for which a few hours sufficed in the first case, require now a whole day, perhaps two. The contending forces cannot remain together near one point; thereby, therefore, the diversity of movements and combinations increases, and, consequently, also the time required. But this places the assailant at a disadvantage, because his difficulty with subsistence being greater, he is obliged to extend his force more than the pursued, and, therefore, is always in danger of being overpowered by the latter at some particular point, as the Russians tried to do at Witepsk.

3. The greater the masses are, the more severe are the exertions demanded from each individual for the daily duties required strategically and tactically. A hundred thousand men who have to march to and from the point of assembly every day, halted at one time, and then set in movement again, now called to arms, then cooking or receiving their rations—a hundred thousand who must not go into their bivouac until the necessary reports are delivered in from all quarters—these men, as a rule, require for all these exertions connected with the actual march, twice as much time as 50,000 would require, but there are only twenty-four hours in the day for both. How much the time and fatigue of the march itself differs according to the size of the body of troops to be moved, has been shown in the ninth chapter of the preceding book. Now, the retreating army, it is true, partakes of these fatigues as well as the advancing, but they are much greater for the latter:—

1. because the mass of his troops is greater on account of the superiority which we supposed,

2. because the defender, by being always the party to yield ground, purchases by this sacrifice the right of the initiative, and, therefore, the right always to give the law to the other. He forms his plan beforehand, which, in most cases, he can carry out unaltered, but the aggressor, on the other hand, can only make his plans conformably to those of his adversary, which he must in the first instance find out.

We must, however, remind our readers that we are speaking of the pursuit of an enemy who has not suffered a defeat, who has not even lost a battle. It is necessary to mention this, in order that we may not be supposed to contradict what was said in the twelfth chapter of our fourth book.

But this privilege of giving the law to the enemy makes a difference in saving of time, expenditure of force, as well as in respect of other minor advantages which, in the long run, becomes very important.

3. because the retreating force on the one hand does all he can to make his own retreat easy, repairs roads, and bridges, chooses the most convenient places for encampment, etc., and, on the other hand again, does all he can to throw impediments in the way of the pursuer, as he destroys bridges, by the mere act of marching makes bad roads worse, deprives the enemy of good places for encampment by occupying them himself, etc.

Lastly, we must add still, as a specially favourable circumstance, the war made by the people. This does not require further examination here, as we shall allot a chapter to the subject itself.

Hitherto, we have been engaged upon the advantages which such a retreat ensures, the sacrifices which it requires, and the conditions which must exist; we shall now say something of the mode of executing it.