If this, the fourth American edition, is bulkier than its predecessors, it is chiefly because the events of the last two years throw an interesting light upon the bearing of the book's main thesis on actual world problems. I have, therefore, added an appendix dealing with certain criticisms based upon the nature of the first Balkan War, in the course of which I attempt to show just how the principles elaborated here have been working out in European politics.
That American interest in the problems here discussed is hardly less vital than that of Europe I am even more persuaded than when the first American edition of this book was issued in 1910. It is certain that opinion in America will not be equipped for dealing with her own problems arising out of her relations with the Spanish American states, with Japan, with the Philippines, unless it has some fair understanding of the principles with which this book deals. Its general interest even goes farther than this: no great community like that of modern America can remain indifferent to the drift of general opinion throughout the world on matters wrapped up with issues so important as those of war and peace.
That the tangible commercial and business interests of America are involved in these European events is obvious from the very factors of financial and commercial interdependence which form the basis of the argument.
That the interests of Americans are inextricably, if indirectly, bound up with those of Europe, has become increasingly clear as can be proved by the barest investigation of the trend of political thought in this country.
The thesis on its economic side is discussed in terms of the gravest problem which now faces European statesmanship, but these terms are also the living symbols of a principle of universal application, as true with reference to American conditions as to European. If I have not "localized" the discussion by using illustrations drawn from purely American cases, it is because these problems have not at present, in the United States, reached the acute stage that they have in Europe, and illustrations drawn from the conditions of an actual and pressing problem give to any discussion a reality which to some extent it might lose if discussed on the basis of more supposititious cases.