Bearing all this in mind, we cannot fail to recognize the truth of the statement that the great wars of the historic period have been either contests between the industrial and the predatory types of society or contests incident upon the imperfect formation of great political aggregates. Throughout the turmoil of the historic period--which on a superficial view seems such a chaos--we see certain definite tendencies at work; the tendency toward the formation of larger and larger political aggregates, and toward the more perfect maintenance of local self-government and individual freedom among the parts of the aggregate. This two-sided process began with the beginnings of industrial civilization; it has aided the progress of industry and been aided by it; and the result has been to diminish the quantity of warfare, and to lessen the number of points at which it touches the ordinary course of civilized life. With the further continuance of this process, but one ultimate result is possible. It must go on until warfare becomes obsolete. The nineteenth century, which has witnessed an unprecedented development of industrial civilization, with its attendant arts and sciences, has also witnessed an unprecedented diminution in the strength of the primeval spirit of militancy. It is not that we have got rid of great wars, but that the relative proportion of human strength which has been employed in warfare has been remarkably less than in any previous age. In our own history, of the two really great wars which have permeated our whole social existence,--the Revolutionary War and the War of Secession,--the first was fought in behalf of the pacific principle of equal representation; the second was fought in behalf of the pacific principle of federalism. In each case, the victory helped to hasten the day when warfare shall become unnecessary. In the few great wars of Europe since the overthrow of Napoleon, we may see the same principle at work. In almost every case the result has been to strengthen the pacific tendencies of modern society. Whereas warfare was once dominant over the face of the earth, and came home in all its horrid details to everybody's door, and threatened the very existence of industrial civilization; it has now become narrowly confined in time and space, it no longer comes home to everybody's door, and, in so far as it is still tolerated, for want of a better method of settling grave international questions, it has become quite ancillary to the paramount needs, of industrial civilization. When we can see so much as this lying before us on the pages of history, we cannot fail to see that the final extinction of warfare is only a question of time. Sooner or later it must come to an end, and the pacific principle of federalism, whereby questions between states are settled, like questions between individuals by due process of law, must reign supreme over all the earth. XIV.