On War

by Carl von Clausewitz

If we admit the second view, then subordinate advantages may be pursued on their own account, and the rest left to subsequent events.

As neither of these forms of conception is entirely without result, therefore theory cannot dispense with either. But it makes this difference in the use of them, that it requires the first to be laid as a fundamental idea at the root of everything, and that the latter shall only be used as a modification which is justified by circumstances.

If Frederick the Great in the years 1742, 1744, 1757, and 1758, thrust out from Silesia and Saxony a fresh offensive point into the Austrian Empire, which he knew very well could not lead to a new and durable conquest like that of Silesia and Saxony, it was done not with a view to the overthrow of the Austrian Empire, but from a lesser motive, namely, to gain time and strength; and it was optional with him to pursue that subordinate object without being afraid that he should thereby risk his whole existence.(*) But if Prussia in 1806, and Austria in 1805, 1809, proposed to themselves a still more moderate object, that of driving the French over the Rhine, they would not have acted in a reasonable manner if they had not first scanned in their minds the whole series of events which either, in the case of success, or of the reverse, would probably follow the first step, and lead up to peace. This was quite indispensable, as well to enable them to determine with themselves how far victory might be followed up without danger, and how and where they would be in a condition to arrest the course of victory on the enemy’s side.

(*) Had Frederick the Great gained the Battle of Kollen, and taken prisoners the chief Austrian army with their two field marshals in Prague, it would have been such a tremendous blow that he might then have entertained the idea of marching to Vienna to make the Austrian Court tremble, and gain a peace directly. This, in these times, unparalleled result, which would have been quite like what we have seen in our day, only still more wonderful and brilliant from the contest being between a little David and a great Goliath, might very probably have taken place after the gain of this one battle; but that does not contradict the assertion above maintained, for it only refers to what the king originally looked forward to from his offensive. The surrounding and taking prisoners the enemy’s army was an event which was beyond all calculation, and which the king never thought of, at least not until the Austrians laid themselves open to it by the unskilful position in which they placed themselves at Prague.

An attentive consideration of history shows wherein the difference of the two cases consists. At the time of the Silesian War in the eighteenth century, war was still a mere Cabinet affair, in which the people only took part as a blind instrument; at the beginning of the nineteenth century the people on each side weighed in the scale. The commanders opposed to Frederick the Great were men who acted on commission, and just on that account men in whom caution was a predominant characteristic; the opponent of the Austrians and Prussians may be described in a few words as the very god of war himself.

Must not these different circumstances give rise to quite different considerations? Should they not in the year 1805, 1806, and 1809 have pointed to the extremity of disaster as a very close possibility, nay, even a very great probability, and should they not at the same time have led to widely different plans and measures from any merely aimed at the conquest of a couple of fortresses or a paltry province?

They did not do so in a degree commensurate with their importance, although both Austria and Prussia, judging by their armaments, felt that storms were brewing in the political atmosphere. They could not do so because those relations at that time were not yet so plainly developed as they have been since from history. It is just those very campaigns of 1805, 1806, 1809, and following ones, which have made it easier for us to form a conception of modern absolute war in its destroying energy.

Theory demands, therefore, that at the commencement of every war its character and main outline shall be defined according to what the political conditions and relations lead us to anticipate as probable. The more, that according to this probability its character approaches the form of absolute war, the more its outline embraces the mass of the belligerent states and draws them into the vortex, so much the more complete will be the relation of events to one another and the whole, but so much the more necessary it will also be not to take the first step without thinking what may be the last.

B. On the Magnitude of the Object of the War, and the Efforts to be Made.

The compulsion which we must use towards our enemy will be regulated by the proportions of our own and his political demands. In so far as these are mutually known they will give the measure of the mutual efforts; but they are not always quite so evident, and this may be a first ground of a difference in the means adopted by each.