A large area means varied vicinal locations and hence differentiation of civilization, at least along the frontier.  How rapidly the vivifying influences of this contact will penetrate into the bulk of the interior depends upon size, location as scattered or compact, and general geographic conditions like navigable rivers or mountains, which facilitate or bar intercourse with that interior.  The Russian Empire has eleven different nations, speaking even more different languages, on its western and southern frontiers.  Its long line of Asiatic contact will inevitably give to the European civilization transplanted hither in Russian colonies a new and perhaps not unfruitful development.  The Siberian citizen of future centuries may compare favorably with his brother in Moscow.  Japan, even while impressing its civilization upon the reluctant Koreans, will see itself modified by the contact and its culture differentiated by the transplanting; but the content of Japanese civilization will be increased by every new variant thus formed.

[Sidenote:  Politico-economic advantages.]

The larger the area brought under one political control, the less the handicap of internal friction and the greater its economic independence.  Vast territory has enabled the United States to maintain with advantage a protective tariff, chiefly because the free trade within its own borders was extensive.  The natural law of the territorial growth of states and peoples means an extension of the areas in which peace and cooeperation are preserved, a relative reduction of frontiers and of the military forces necessary to defend them,[316] diminution in the sum total of conflicts, and a wider removal of the border battle fields.  In place of the continual warfare between petty tribes which prevailed in North America four hundred years ago, we have to-day the peaceful competition of the three great nations which have divided the continent among them.  The political unification of the Mediterranean basin under the Roman Empire restricted wars to the remote land frontiers.  The foreign wars of Russia, China, and the United States in the past century have been almost wholly confined to the outskirts of their big domains, merely scratching the rim and leaving the great interior sound and undisturbed.  Russia’s immense area is the military ally on which she can most surely count.  The long road to Moscow converted Napoleon’s victory into a defeat; and the resistless advance of the Japanese from Port Arthur to the Sungari River led only to a peace robbed of the chief fruits of victory.  The numerous wars of the British Empire have been limited to this or that corner, and have scarcely affected the prosperity of the great remainder, so that their costs have been readily borne and their wounds rapidly healed.

[Sidenote:  Political area and the national horizon.]