But when one nation finds itself in strong competition with another in the hope of controlling a sphere of trade, it is apt to seek territorial annexation to gain the desired field of exploitation. The competitor can only follow the same course. It is the only thing it can do, if it is not willing to give up the contest. If it is strong enough to dispute the will of the rival, its very sense of individuality demands that it shall not tamely yield before the aggression of a rival. When France acquired Morocco, Italy acquired Tripoli, and Great Britain acquired the southern part of Persia, economic advantage was a strong motive, but not the only motive. When Germany laid out the field of her future expansion in Turkish lands and when she expected to establish a permanent influence over the Balkans, the extension of her sphere of commerce was a chief motive. Probably the fundamental wrong here was the idea, widely held by the present generation, that a nation has a right to establish bars around her national territory to keep the trade of other nations out, so that her own citizens shall have preferential advantages in the exploitation of the territory. That idea is so firmly held today that one must be a rash man who attempts to get the nations to give it up. But it is a fundamental obstacle to permanent peace in the world. Probably it is not too much to say that as long as the business men of the world insist on dividing themselves into national groups with these national preferences, so long may they expect business at recurring intervals to be burdened with the waste and ruin of war. Against the existing practice we may place the “open door” policy, which we have known chiefly in connection with the trade of the undeveloped nations. It means the free opening of the trade of a given state to all the nations that may care to have it. We heard much of the “open door” in China a few years ago, and most of the benevolent governments approved of the suggestion. To have been perfectly logical they should have applied the same idea to their own commerce; and if the world ever comes to a perfect state of international comity, it is likely that national tariff barriers will be broken down. It is true, however, that we can have enduring peace and have national protective tariffs, also. If nations agree that tariffs are one of the unhappy excrescences of an unreasonable world, they may find it in their hearts to tolerate such growths. To tolerate them would be, no doubt, better than going to war. But when a state sets its eyes on a certain part of the earth which it feels it must acquire in order to enlarge the territory in which it can trade without fair competition, the peace of the world is imperiled.