Defence, however, consists of two different elements, these are the decision and the state of expectation. The combination of these two elements forms the subject of this chapter.
First we must observe that the state of expectation is not, in point of fact, the complete defence; it is only that province of the same in which it proceeds to its aim. As long as a military force has not abandoned the portion of territory placed under its guardianship, the tension of forces on both sides created by the attack continues, and this lasts until there is a decision. The decision itself can only be regarded as having actually taken place when either the assailant or defender has left the theatre of war.
As long as an armed force maintains itself within its theatre, the defence of the same continues, and in this sense the defence of the theatre of war is identical with the defence in the same. Whether the enemy in the meantime has obtained possession of much or little of that section of country is not essential, for it is only lent to him until the decision.
But this kind of idea by which we wish to settle the proper relation of the state of expectation to the whole is only correct when a decision is really to take place, and is regarded by both parties as inevitable. For it is only by that decision that the centres of gravity of the respective forces, and the theatre of war determined through them are effectually hit. Whenever the idea of a decisive solution disappears, then the centres of gravity are neutralised, indeed, in a certain sense, the whole of the armed forces become so also, and now the possession of territory, which forms