As shown in the struggle recently ended, modern war means “a nation in arms.” The old-time distinction between fighters and workers was almost obliterated, and there was an industrial army as well as an army in the field. The labors of the men and women behind the lines were essential to the effective operations of the men in arms. That this condition was recognized by the governments themselves is shown by the classifications of workers, according to which those whose special skill or ability was essential to the conduct of war industries were taken out or kept out of the army and retained in the factories, mines, workshops, and fields. In various ways the old lines between soldier and civilian, between war operations and the work of production, were broken down. The Germans made no distinction between war vessels and merchantmen. They deliberately destroyed coal mines and factories, growing crops and cattle; this was done with a military purpose, for the sake of lessening the military strength of the enemy. So, too, the former distinction between contraband and free goods was obliterated. Whole nations were in arms, and all their resources were mobilized to carry on the titanic struggle.

This world conflict has taught us that war is not waged altogether by armies in the field. It is a contest between the industrial organization and technique of the opposing nations. It is not carried on by money alone, but by the total resources, material and human, that can be concentrated in a combined, productive effort. The World War gave the first opportunity for a complete application of the modern factory system of production in warfare.