Clausewitz is the great thinker, the great realist, the great philosopher of war. His aim was, free from all bias, to get at the truth of things. His view of war as a social act, as part of the intercourse of nations, so that occasional warlike struggles can no more be avoided than occasional commercial struggles, is a view which requires to be most carefully pondered over by every statesman. It is based upon the essential fundamental characteristics of human nature, which do not alter. It is not to be lightly set aside by declamation about the blessings of peace, the evils of war, the burden of armaments, and such-like sophistries. To submit without a struggle to injustice or to the destruction of one's vital interests is not in passionate human nature. Nor will it ever be in the nature of a virile people. It is indeed to be most sincerely hoped that arbitration will be resorted to more and more as a means of peacefully settling all non-vital causes of dispute. But arbitration has its limits. For no great nation will ever submit to arbitration any interest that it regards as absolutely vital. The view of war, therefore, as a social act, as part of the intercourse of nations, with all that it implies, appears to be the only one which a statesman, however much he may regret the fact, can take. It has, therefore, been brought forward here at once, as it underlies the whole subject and is essential to all clear thought thereon.
So much for the influence of Public Opinion in producing war. Now for its influence in and during war.
"There are three principal objects in carrying on war," says Clausewitz.
"(a) To conquer and destroy the enemy's armed force.
"(b) To get possession of the material elements of aggression, and of the other sources of existence of the hostile army.
"(c) To gain Public Opinion.[15]
"To attain the first of these objects, the chief operation must be directed against the enemy's principal army, for it must be beaten before we can follow up the other two objects with success.
"In order to seize the material forces, operations are directed against those points at which those resources are chiefly concentrated: principal towns, magazines, great fortresses. On the road to these the enemy's principal force, or a considerable part of his army, will be encountered.
"Public Opinion is ultimately gained by great victories, and by the possession of the enemy's capital."[16]
This almost prophetic (as it was in his day) recognition by Clausewitz of the vast importance of gaining Public Opinion as one of the three great aims in war, is fundamental. It is just one of those instances of his rare insight into the principles and development of modern national war which make his book of such great and enduring value to us. For since his day Europe has become organized into great industrial nations, democracy and popular passion have become more and more a force to be reckoned with, and the gaining and preserving of Public Opinion in war has become more and more important. It has, in fact, become the statesman's chief business during a great modern national war. It has become necessary for him to study intently war in its relation to industry, and to the industrial millions over whom he presides, or over whom he may preside.