On War

by Carl von Clausewitz

This means is necessarily one of those provided for that defence of a country which we are now considering. In the first place the defender, even with the most extended position, often cannot guard all the approaches to his country which are menaced; next, in many cases, he must be ready to repair with the bulk of his forces to any posts upon which the bulk of the enemy’s force is about to be thrown, as otherwise those posts would be too easily overpowered; lastly, a general who has an aversion to confining his army to a passive resistance in an extended position, must seek to attain his object, the protection of the country, by rapid, well-planned, and well-conducted movements. The greater the spaces which he leaves exposed, the greater the talent required in planning the movements, in order to arrive anywhere at the right moment of time.

The natural consequence of striving to do this is, that in such a case, positions which afford sufficient advantages to make an enemy give up all idea of an attack as soon as our army, or only a portion of it, reaches them, are sought for and prepared in all directions. As these positions are again and again occupied, and all depends on reaching the same in right time, they are in a certain measure the vowels of all this method of carrying on war, which on that account has been termed a war of posts.

Just as an extended position, and the relative resistance in a war without great decisions, do not present the dangers which are inherent in its original nature, so in the same manner the intercepting the enemy in front by a march to a flank is not so hazardous as it would be in the immediate expectation of a great decision. To attempt at the last moment in greatest haste (by a lateral movement) to thrust in an army in front of an adversary of determined character, who is both able and willing to deal heavy blows, and has no scruples about an expenditure of forces, would be half way to a most decisive disaster; for against an unhesitating blow delivered with the enemy’s whole strength, such running and stumbling into a position would not do. But against an opponent who, instead of taking up his work with his whole hand, uses only the tips of his fingers, who does not know how to make use of a great result, or rather of the opening for one, who only seeks a trifling advantage but at small expense, against such an opponent this kind of resistance certainly may be applied with effect.

A natural consequence is, that this means also in general occurs oftener in the last half of a campaign than at its commencement.

Here, also, the general staff has an opportunity of displaying its topographical knowledge in framing a system of combined measures, connected with the choice and preparation of the positions and the roads leading to them.

When the whole object of one party is to gain in the end a certain point, and the whole object of his adversary, on the other hand, is to prevent his doing so, then both parties are often obliged to make their movements under the eyes of each other; for this reason, these movements must be made with a degree of precaution and precision not otherwise required. Formerly, before the mass of an army was formed of independent divisions, and even on the march was always regarded as an indivisible whole, this precaution and precision was attended with much more formality, and with the copious use of tactical skill. On these occasions, certainly, single brigades were often obliged to leave the general line of battle to secure particular points, and act an independent part until the army arrived: but these were, and continued, anomalous proceedings; and the aim in the order of march generally was to move the army from one point to another as a whole, preserving its normal formation, and avoiding such exceptional proceedings as the above as far as possible. Now that the parts of the main body of an army are subdivided again into independent bodies, and those bodies can venture to enter into an engagement with the mass of the enemy’s army, provided the rest of the force of which it is a member is sufficiently near to carry it on and finish it,—now such a flank march is attended with less difficulty even under the eye of the enemy. What formerly could only be effected through the actual mechanism of the order of march, can now be done by starting single divisions at an earlier hour, by hastening the march of others, and by the greater freedom in the employment of the whole.

By the means of defence just considered, the assailant can be prevented from taking any fortress, from occupying any important extent of country, or capturing magazines; and he will be prevented, if in every direction combats are offered to him in which he can see little probability of success, or too great danger of a reaction in case of failure, or in general, an expenditure of force too great for his object and existing relations.

If now the defender succeeds in this triumph of his art and skill, and the assailant, wherever he turns his eyes, sees prudent preparations through which he is cut off from any prospect of attaining his modest wishes: then the offensive principle often seeks to escape from the difficulty in the satisfaction of the mere honour of its arms. The gain of some combat of respectable importance, gives the arms of the victor a semblance of superiority, appeases the vanity of the general, of the court, of the army, and the people, and thus satisfies, to a certain extent, the expectations which are naturally always raised when the offensive is assumed.

An advantageous combat of some importance merely for the sake of the victory and some trophies, becomes, therefore, the last hope of the assailant. No one must suppose that we here involve ourselves in a contradiction, for we contend that we still continue within our own supposition, that the good measures of the defender have deprived the assailant of all expectation of attaining any one of those other objects by means of a successful combat! To warrant that expectation, two conditions are required, that is, a favourable termination to the combat, and next, that the result shall lead really to the attainment of one of those objects.

The first may very well take place without the second, and therefore the defenders’ corps and posts singly are much more frequently in danger of getting involved in disadvantageous combats if the assailant merely aims at the honour of the battle field, than if he connects with that a view to further advantages as well.