Such a view of the subject was of course a wide departure from the theory of “Absolute War” on which Clausewitz had started working.  Under that theory “Absolute War” was the ideal form to which all war ought to attain, and those which fell short of it were imperfect wars cramped by a lack of true military spirit.  But so soon as he had seized the fact that in actual life the moral factor always must override the purely military factor, he saw that he had been working on too narrow a basis—­a basis that was purely theoretical in that it ignored the human factor.  He began to perceive that it was logically unsound to assume as the foundation of a strategical system that there was one pattern to which all wars ought to conform.  In the light of his full and final apprehension of the value of the human factor he saw wars falling into two well-marked categories, each of which would legitimately be approached in a radically different manner, and not necessarily on the lines of “Absolute War.”

He saw that there was one class of war where the political object was of so vital an importance to both belligerents that they would tend to fight to the utmost limit of their endurance to secure it.  But there was another class where the object was of less importance, that is to say, where its value to one or both the belligerents was not so great as to be worth unlimited sacrifices of blood and treasure.  It was these two kinds of war he designated provisionally “Unlimited” and “Limited,” by which he meant not that you were not to exert the force employed with all the vigour you could develop, but that there might be a limit beyond which it would be bad policy to spend that vigour, a point at which, long before your force was exhausted or even fully developed, it would be wiser to abandon your object rather than to spend more upon it.

This distinction it is very necessary to grasp quite clearly, for it is often superficially confused with the distinction already referred to, which Clausewitz drew in the earlier part of his work—­that is, the distinction between what he called the character of modern war and the character of the wars which preceded the Napoleonic era.  It will be remembered he insisted that the wars of his own time had been wars between armed nations with a tendency to throw the whole weight of the nation into the fighting line, whereas in the seventeenth and eighteenth centuries wars were waged by standing armies and not by the whole nation in arms.  The distinction of course is real and of far-reaching consequences, but it has no relation to the distinction between “Limited” and “Unlimited” war.  War may be waged on the Napoleonic system either for a limited or an unlimited object.

A modern instance will serve to clear the field.  The recent Russo-Japanese War was fought for a limited object—­the assertion of certain claims over territory which formed no part of the possessions of either belligerent.  Hostilities were conducted on entirely modern lines by two armed nations and not by standing armies alone.  But in the case of one belligerent her interest in the object was so limited as to cause her to abandon it long before her whole force as an armed nation was exhausted or even put forth.  The expense of life and treasure which the struggle was involving was beyond what the object was worth.