War in the twentieth century is no longer the extension of politics by other means. It is doubtful whether the aphorism affirming that war is such an extension of politics was ever true enough to warrant the frequency with which it has been repeated. War once begun has always tended to generate a politics of its own: to create its own momentum, to render obsolete the political purposes for which it was undertaken, and to erect its own political imperatives. In the twentieth century, as the present collection of essays attests, the hypertrophy of war through war's assumption of global dimensions and almost unlimited destructiveness has led most emphatically to the emergence of war not as the servant but as the master of politics.

Twentieth-century warfare sets its own purposes. A war begun to quarantine the Austro–Hungarian Empire against the seditious activities of little Serbia among the empire's Slavic populations generates so much military and political momentum that it cannot end until all the great powers of Europe have been so completely defeated or exhausted that four centuries of European political hegemony over the rest of the world are ended. A war precipitated by American economic sanctions intended to punish Japan for its military occupation of a remote corner of southeast Asia leads to the shadowing of the globe by the threat of nuclear destruction.

In consequence of war's assumption of its own momentum and purposes, the questions to which the chapters in these volumes have addressed themselves regarding the political, strategic, operational, and tactical effectiveness of armed forces have become increasingly difficult to answer.