The consequence of this difference is, that tactics can make a continued use of forces, strategy only a simultaneous one.

If I cannot, in tactics, decide all by the first success, if I have to fear the next moment, it follows of itself that I employ only so much of my force for the success of the first moment as appears sufficient for that object, and keep the rest beyond the reach of fire or conflict of any kind, in order to be able to oppose fresh troops to fresh, or with such to overcome those that are exhausted. But it is not so in strategy. Partly, as we have just shown, it has not so much reason to fear a reaction after a success realised, because with that success the crisis stops; partly all the forces strategically employed are not necessarily weakened. Only so much of them as have been tactically in conflict with the enemy’s force, that is, engaged in partial combat, are weakened by it; consequently, only so much as was unavoidably necessary, but by no means all which was strategically in conflict with the enemy, unless tactics has expended them unnecessarily. Corps which, on account of the general superiority in numbers, have either been little or not at all engaged, whose presence alone has assisted in the result, are after the decision the same as they were before, and for new enterprises as efficient as if they had been entirely inactive. How greatly such corps which thus constitute our excess may contribute to the total success is evident in itself; indeed, it is not difficult to see how they may even diminish considerably the loss of the forces engaged in tactical conflict on our side.

If, therefore, in strategy the loss does not increase with the number of the troops employed, but is often diminished by it, and if, as a natural consequence, the decision in our favour is, by that means, the more certain, then it follows naturally that in strategy we can never employ too many forces, and consequently also that they must be applied simultaneously to the immediate purpose.

But we must vindicate this proposition upon another ground. We have hitherto only spoken of the combat itself; it is the real activity in war, but men, time, and space, which appear as the elements of this activity, must, at the same time, be kept in view, and the results of their influence brought into consideration also.

Fatigue, exertion, and privation constitute in war a special principle of destruction, not essentially belonging to contest, but more or less inseparably bound up with it, and certainly one which especially belongs to strategy. They no doubt exist in tactics as well, and perhaps there in the highest degree; but as the duration of the tactical acts is shorter, therefore the small effects of exertion and privation on them can come but little into consideration. But in strategy on the other hand, where time and space are on a larger scale, their influence is not only always very considerable, but often quite decisive. It is not at all uncommon for a victorious army to lose many more by sickness than on the field of battle.

If, therefore, we look at this sphere of destruction in strategy in the same manner as we have considered that of fire and close combat in tactics, then we may well imagine that everything which comes within its vortex will, at the end of the campaign or of any other strategic period, be reduced to a state of weakness, which makes the arrival of a fresh force decisive. We might therefore conclude that there is a motive in the one case as well as the other to strive for the first success with as few forces as possible, in order to keep up this fresh force for the last.

In order to estimate exactly this conclusion, which, in many cases in practice, will have a great appearance of truth, we must direct our attention to the separate ideas which it contains. In the first place, we must not confuse the notion of reinforcement with that of fresh unused troops. There are few campaigns at the end of which an increase of force is not earnestly desired by the conqueror as well as the conquered, and indeed should appear decisive; but that is not the point here, for that increase of force could not be necessary if the force had been so much larger at the first. But it would be contrary to all experience to suppose that an army coming fresh into the field is to be esteemed higher in point of moral value than an army already in the field, just as a tactical reserve is more to be esteemed than a body of troops which has been already severely handled in the fight. Just as much as an unfortunate campaign lowers the courage and moral powers of an army, a successful one raises these elements in their value. In