But now, if the defender does not think he requires any assistance from these immovable forces for his purposed decision, or if the further sacrifice connected with the use of them is too great, then they are kept in reserve for the future, and form a sort of succession of reinforcements, which perhaps ensure the possibility of keeping the moveable forces in such a condition that they will be able to follow up the first favourable decision with a second, or perhaps in the same manner even with a third, that is to say, in this manner a successive application of his forces becomes possible.
If the defender loses a battle on the frontier, which does not amount to a complete defeat, we may very well imagine that, by placing himself behind the nearest fortress, he will then be in a condition to accept battle again; indeed, if he is only dealing with an opponent who has not much resolution, then, perhaps, some considerable obstacle of ground will be quite sufficient as a means of stopping the enemy.
There is, therefore, in strategy, in the use of the theatre of war as well as in everything else, an economy of force; the less one can make suffice the better: but there must be sufficient, and here, as well as in commerce, there is something to be thought of besides mere niggardliness.
But in order to prevent a great misconception, we must draw attention to this, that the subject of our present consideration is not how much resistance an army can offer, or the enterprises which it can undertake after a lost battle, but only the result which we can promise ourselves beforehand from this second act in our defence; consequently, how high we can estimate it in our plan. Here there is only one point almost which the defender has to look to, which is the character and the situation of his opponent. An adversary weak in character, with little self-confidence, without noble ambition, placed under great restrictions, will content himself, in case he is successful, with a moderate advantage, and timidly hold back at every fresh offer of a decision which the defender ventures