On War

by Carl von Clausewitz

What is now the solution generally?

We have always supposed it in our observations in the form of a battle; but in reality, this is not necessary, for a number of combinations of battles with separate corps may be imagined, which may bring about a change of affairs, either because they have really ended with bloodshed, or because their probable result makes the retreat of the enemy necessary.

Upon the theatre of war itself there can be no other solution; that is a necessary consequence of our view of war; for, in fact, even if an enemy’s army, merely from want of provisions, commences his retreat, still it takes place from the state of restraint in which our sword holds him; if our army was not in the way he would soon be able to provision his forces.

Therefore, even at the end of his aggressive course, when the enemy is suffering the heavy penalty of his attack, when detachments, hunger, and sickness have weakened and worn him out, it is still always the dread of our sword which causes him to turn about, and allow everything to go on again as usual. But nevertheless, there is a great difference between such a solution and one which takes place on the frontier.

In the latter case our arms only were opposed to his to keep him in check, or carry destruction into his ranks; but at the end of the aggressive career the enemy’s forces, by their own exertions, are half destroyed, by which our arms acquire a totally different value, and therefore, although they are the final they are not the only means which have produced the solution. This destruction of the enemy’s forces in the advance prepares the solution, and may do so to this extent, that the mere possibility of a reaction on our part may cause the retreat, consequently a reversal of the situation of affairs. In this case, therefore, we can practically ascribe the solution to nothing else than the efforts made in the advance. Now, in point of fact we shall find no case in which the sword of the defensive has not co-operated; but, for the practical view, it is important to distinguish which of the two principles is the predominating one.

In this sense we think we may say that there is a double solution in the defensive, consequently a double kind of reaction, according as the aggressor is ruined by the sword of the defensive, or by his own efforts.

That the first kind of solution predominates in the first three steps of the defence, the second in the fourth, is evident in itself; and the latter will, in most cases, only come to pass by the retreat being carried deep into the heart of the country, and nothing but the prospect of that result can be a sufficient motive for such a retreat, considering the great sacrifices which it must cost.

We have, therefore, ascertained that there are two different principles of defence; there are cases in military history where they each appear as separate and distinct as it is possible for an elementary conception to appear in practical life. When Frederick the Great attacked the Austrians at Hohenfriedberg, just as they were descending from the Silesian mountains, their force could not have been weakened in any sensible manner by detachments or fatigue; when, on the other hand, Wellington, in his entrenched camp at Torres Vedras, waited till hunger, and the severity of the weather, had reduced Massena’s army to such extremities that they commenced to retreat of themselves, the sword of the defensive party had no share in the weakening of the enemy’s army. In other cases, in which they are combined with each other in a variety of ways, still, one of them distinctly predominates. This was the case in the year 1812. In that celebrated campaign such a number of bloody encounters took place as might, under other circumstances, have sufficed for a most complete decision by the sword; nevertheless, there is hardly any campaign in which we can so plainly see how the aggressor may be ruined by his own efforts. Of the 300,000 men composing the French centre only about 90,000 reached Moscow; not more than 13,000 were detached; consequently there had been a loss of 197,000 men, and certainly not a third of that loss can be put to account of battles.

All campaigns which are remarkable for temporising, as it is called, like those of the famous Fabius Cunctator, have been calculated chiefly on the destruction of the enemy by his own efforts. This principle has been the leading one in many campaigns without that point being almost ever mentioned; and it is only when we disregard the specious reasoning of historians, and look at things clearly with our own eyes, that we are led to this real cause of many a solution.

By this we believe we have unravelled sufficiently those ideas which lie at the root of the defensive, and that in the two great kinds of defence we have shown plainly and made intelligible how the principle of the waiting for runs through the whole system and connects itself with positive action in such a manner that, sooner or later, action does take place, and that then the advantage of the attitude of waiting for appears to be exhausted.