EVEN if the complete overthrow of the enemy cannot be the object, there may still be one which is directly positive, and this positive object can be nothing else than the conquest of a part of the enemy's country.
The use of such a conquest is this, that we weaken the enemy's resources generally, therefore, of course, his military power, while we increase our own; that we therefore carry on the war, to a certain extent, at his expense; further in this way, that in negotiations for peace, the possession of the enemy's provinces may be regarded as net gain, because we can either keep them or exchange them for other advantages.
This view of a conquest of the enemy's provinces is very natural, and would be open to no objection if it were not that the defensive attitude, which must succeed the offensive, may often cause uneasiness.
In the chapter on the culminating point of victory we have sufficiently explained the manner in which such an offensive weakens the combatant force, and that it may be succeeded by a situation causing anxiety as to the future.
This weakening of our combatant force by the conquest of part of the enemy's territory has its degrees, and these depend chiefly on the geographical position of this portion of territory. The more it is an annex of our own country, being contiguous to or embraced by it, the more it is in the direction of our principal force, by so much the less will it weaken our combatant force. In the Seven Years' War, Saxony was a natural complement of the Prussian theatre of war, and Frederick the Great's army, instead of being weakened, was strengthened by the possession of that province, because it lies nearer to Silesia than to the Mark, and at the same time covers the latter.
Even in 1740 and 1741, after Frederick the Great had once conquered Silesia, it did not weaken his army in the field, because, owing to its form and situation as well as the contour of its frontier line, it only presented a narrow point to the Austrians, as long as they were not masters of Saxony, and besides that, this small point of contact also lay in the direction of the chief operations of the contending forces.
If, on the other hand, the conquered territory is a strip running up between hostile provinces, has an eccentric position and unfavourable configuration of ground, then the weakening increases so visibly that a victorious battle becomes not only much easier for the enemy, but it may even become unnecessary as well.
The Austrians have always been obliged to evacuate Provence without a battle when they have made attempts on it from Italy. In the year 1744 the French were very well pleased even to get out of Bohemia without having lost a battle. In 1758 Frederick the Great could not hold his position in Bohemia and Moravia with the same force with which he had obtained such brilliant successes in Silesia and Saxony in 1757. Examples of armies not being able to keep possession of conquered territory solely because their combatant force was so much weakened thereby, are so common that it does not appear necessary to quote any more of them.
Therefore, the question whether we should aim at such an object depends on whether we can expect to hold possession of the conquest or whether a temporary occupation (invasion, diversion) would repay the expenditure of force required: especially, whether we have not to apprehend such a vigorous counterstroke as will completely destroy the balance of forces. In the chapter on the culmination point we have treated of the consideration due to this question in each particular case.
There is just one point which we have still to add.
An offensive of this kind will not always compensate us for what we lose upon other points. Whilst we are engaged in making a partial conquest, the enemy may be doing the same at other points, and if our enterprise does not greatly preponderate in importance then it will not compel the enemy to give up his. It is, therefore, a question for serious consideration whether we may not lose more than we gain in a case of this description.
Even if we suppose two provinces (one on each side) to be of equal value, we shall always lose more by the one which the enemy takes from us than we can gain by the one we take, because a number of our forces become to a certain extent like faux frais, non-effective. But as the same takes place on the enemy's side also, one would suppose that in reality there is no ground to attach more importance to the maintenance of what is our own than to the conquest. But yet there is. The maintenance of our own territory is always a matter which more deeply concerns us, and the suffering inflicted on our own state can not be outweighed, nor, to a certain extent, neutralised by what we gain in return, unless the latter promises a high percentage, that is, is much greater.
The consequence of all this is that a strategic attack directed against only a moderate object involves a greater necessity for steps to defend other points which it does not directly cover than one which is directed against the centre of the enemy's force; consequently, in such an attack the concentration of forces in time and space cannot be carried out to the same extent. In order that it may take place, at least as regards time, it becomes necessary for the advance to be made offensively from every point possible, and at the same moment exactly: and therefore this attack loses the other advantage of being able to make shift with a much smaller force by acting on the defensive at particular points. In this way the effect of aiming at a minor object is to bring all things more to a level: the whole act of the war cannot now be concentrated into one principal affair which can be governed according to leading points of view; it is more dispersed; the friction becomes greater everywhere, and there is everywhere more room for chance.
This is the natural tendency of the thing. The commanders weighed down by it, finds himself more and more neutralised. The more he is conscious of his own powers, the greater his resources subjectively, and his power objectively, so much the more he will seek to liberate himself from this tendency in order to give to some one point a preponderating importance, even if that should only be possible by running greater risks.