We must here make a distinction between the cases of a position which is occupied by the main body, and one only occupied by an inferior force.
In the first case the passing by the position can only benefit the assailant, if, besides the principal force of the defendant, there is also some other attainable and decisive object of attack, as, for instance, the capture of a fortress or a capital city, etc. But even if there is such an object, he can only follow it if the strength of his base and the direction of his lines of communication are such that he has no cause to fear operations against his strategic flanks.
The conclusions to be drawn from this with respect to the admissibility and eligibility of a strong position for the main body of the defender’s army are, that it is only an advisable position when either the possibility of operating against the strategic flank of the aggressor is so decisive that we may be sure beforehand of being able in that way to keep him at a point where his army can effect nothing, or in a case where there is no object attainable by the aggressor for which the defence need be uneasy. If there is such an object, and the strategic flank of the