This article examines the strategic decisions that led to the struggle between Britain and Germany, exploring how a great war involving Europe’s leading powers could come to pass. In 1914, there were no forces beyond the control of decision makers pushing them into the grisly war of attrition that destroyed the social and political fabric of nineteenth-century Europe and ushered in the horrors of the twentieth century. Rather, those horrors resulted from poor policy and strategic choices made by the leaders of the great powers. The war’s outbreak underscores history’s contingent nature, dramatically showing how errors in judgment on the part of political and military leaders can ruin great countries. One stark lesson of the Great War is that no leader sought as an outcome the conflagration produced by their decisions. Today, China’s weapons programs and foreign policy assertiveness conjures up fears that Beijing seeks to establish a new international order, much as Germany’s rulers tried to do a hundred years ago with such catastrophic consequences. Shaping the internal debate among China’s rulers, so that they judge self-restraint in armaments and strategy as being in their best interest, will test the strategic acumen of American leaders in the years ahead.