The disposition of everyone on all sides not to prepare for the harder alternative, not to act upon what they suspected to be true

From the Guns of August by Barbara Tuchman.

The goal, decisive battle, was a product of the victories over Austria and France in 1866 and 1870. Dead battles, like dead generals, hold the military mind in their dead grip, and Germans, no less than other peoples, prepare for the last war. They staked everything on decisive battle in the image of Hannibal, but even the ghost of Hannibal might have reminded Schlieffen that though Carthage won at Cannae, Rome won the war.

Old Field Marshal Moltke in 1890 foretold that the next war might last seven years—or thirty—because the resources of a modern state were so great it would not know itself to be beaten after a single military defeat and would not give up. His nephew and namesake who succeeded Schlieffen as Chief of Staff also had moments when he saw the truth as clearly. In a moment of heresy to Clausewitz, he said to the Kaiser in 1906, “It will be a national war which will not be settled by a decisive battle but by a long wearisome struggle with a country that will not be overcome until its whole national force is broken, and a war which will utterly exhaust our own people, even if we are victorious.” It went against human nature, however—and the nature of General Staffs—to follow through the logic of his own prophecy. Amorphous and without limits, the concept of a long war could not be scientifically planned for as could the orthodox, predictable, and simple solution of decisive battle and a short war. The younger Moltke was already Chief of Staff when he made his prophecy, but neither he nor his Staff, nor the Staff of any other country, ever made any effort to plan for a long war. Besides the two Moltkes, one dead and the other infirm of purpose, some military strategists in other countries glimpsed the possibility of prolonged war, but all preferred to believe, along with the bankers and industrialists, that because of the dislocation of economic life a general European war could not last longer than three or four months. One constant among the elements of 1914—as of any era — was the disposition of everyone on all sides not to prepare for the harder alternative, not to act upon what they suspected to be true.