From ON WAR: Chapter II
If, in the next place, we keep once more to the pure conception of war, then we must say that its political object properly lies out of its province, for if war is an act of violence to compel the enemy to fulfil our will, then in every case all depends on our overthrowing the enemy, that is, disarming him, and on that alone. This object, developed from abstract conceptions, but which is also the one aimed at in a great many cases in reality, we shall, in the first place, examine in this reality.
In connection with the plan of a campaign we shall hereafter examine more closely into the meaning of disarming a nation, but here we must at once draw a distinction between three things, which as three general objects comprise everything else within them. They are the military power, the country, and the will of the enemy.
The military power must be destroyed , that is, reduced to such a state as not to be able to prosecute the war. This is the sense in which we wish to be understood hereafter, whenever we use the expression "destruction of the enemy's military power."
The country must be conquered , for out of the country a new military force may be formed.
But if even both these things are done, still the war, that is, the hostile feeling and action of hostile agencies, cannot be considered as at an end as long as also the will of the enemy is not subdued ; that is, its Government and its allies forced into signing a peace, or the people into submission; for whilst we are in full occupation of the country the war may break out afresh, either in the interior or through assistance given by allies. No doubt this may also take place after a peace, but that shows nothing more than that every war does not carry in itself the elements for a complete decision and final settlement.