So great are the psychological resistances to war in modern nations, that every war must appear to be a war of defense against a menacing, murderous aggressor. There must be no ambiguity about whom the public is to hate. The war must not be due to a world system of conducting international affairs, nor to the stupidity or malevolence of all governing classes, but to the rapacity of the enemy. Guilt and guilelessness must be assessed geographically, and all the guilt must be on the other side of the frontier. If the propagandist is to mobilize the hate of the people, he must see to it that everything is circulated which establishes the sole responsibility of the enemy.