Scholars began arguing over the Great War’s origins soon after it began, and the debate continues a century after its end. The victorious Allied powers expressed their opinion — that Germany caused the war — in the Versailles treaty. But history seldom offers such simple answers, particularly to questions so complex. The war’s origins lie in the nineteenth century, and its immediate causes lie in the few years and months before the war, especially one particular morning in June 1914.

Any study of the Great War’s origins (or indeed, of nearly every war in the twentieth century) must begin with nationalism (see Chapter 24), one of the major ideologies of the nineteenth century, and its armed companion, militarism, the glorification of the military as the supreme ideal of the state with all other interests subordinate to it. European concerns over national security, economies, welfare, identities, and overseas empires set nation against nation, alliance against alliance, and army against army until they all went to war at once.

Competition between nations intensified greatly when Germany became a unified nation-state and the most powerful country in Europe, after defeating France in the Franco-Prussian War of 1870–1871 (see “Bismarck and German Unification” in Chapter 24). A new era in international relations began, as Chancellor Bismarck declared Germany a “satisfied” power, having no territorial ambitions within Europe and desiring only peace.

But how to preserve the peace? Bismarck’s first concern was to keep rival France diplomatically isolated and without military allies. His second concern was to prevent Germany from being dragged into a great war between the two rival empires, Austria-Hungary and Russia, as they sought to fill the power vacuum created in the Balkans by the Ottoman Empire’s decline (see “Decline and Reform in the Ottoman Empire” in Chapter 25). In 1873 the emperors of Germany, Russia, and Austria-Hungary formed the Three Emperors’ League in an effort to maintain a balance of power in Europe and avoid war. In 1878 Bismarck negotiated the Treaty of Berlin, which attempted to settle various claims to Balkan lands. Bismarck’s balancing efforts infuriated Russian nationalists, who believed he favored Austria. The Three Emperors’ League fell apart, and Bismarck formed a defensive military alliance with Austria against Russia in 1879. Motivated by tensions with France, newly unified Italy joined Germany and Austria to form the Triple Alliance in 1882. In 1884–1885 Bismarck convened the Berlin Conference to prevent conflicts over empire by laying the ground rules for the colonization of Africa and Asia (see “The Scramble for Africa, 1880–1914” in Chapter 25). He also signed a secret nonaggression treaty in 1887 with Russia, in which both states promised neutrality if the other was attacked. Here he sought to prevent Germany from being caught in a two-front war with Russia and France.

In 1890 Germany’s new emperor, William II, forced Bismarck to resign and then abandoned many of Bismarck’s efforts to ensure German security through promoting European peace and stability. William refused to renew Bismarck’s nonaggression pact with Russia, for example, which prompted France to court the tsar, offering loans and arms, and sign a Franco-Russian Alliance in 1892. Great Britain’s foreign policy now became increasingly crucial. After 1892 Britain was the only uncommitted Great Power. Many Germans and some Britons felt that the racially related Germanic and Anglo-Saxon peoples were natural allies. However, the good relations that had prevailed between Prussia and Great Britain since the mid-eighteenth century gave way after 1890 to a bitter Anglo-German rivalry.

There were several reasons for this development. Germany and Great Britain’s commercial rivalry in world markets and Kaiser William’s publicly expressed intention to create a global German empire unsettled the British. Germany’s decision in 1900 to add an enormously expensive fleet of big-gun battleships to its already-expanding navy also heightened tensions. German nationalists/militarists saw a large navy as the legitimate mark of a great world power. But British leaders considered it a military challenge to their long-standing naval supremacy, which forced them to spend the “People’s Budget” (see “Great Britain and the Austro-Hungarian Empire” in Chapter 24) on battleships rather than on social welfare. This decision coincided with the South African War (see “Southern Africa in the Nineteenth Century” in Chapter 25) between the British and the Afrikaners, which revealed widespread anti-British feeling around the world.

Thus British leaders prudently set about shoring up their exposed position with their own alliances and agreements. Britain improved its relations with the United States, concluded an alliance with Japan in 1902, and in the Anglo-French Entente of 1904 settled all outstanding colonial disputes with France. Frustrated by Britain’s closer relationship with France, Germany’s leaders decided to test the entente’s strength by demanding an international conference to challenge French control (with British support) over Morocco. At the Algeciras (Spain) Conference in 1906, Germany’s crude bullying only forced France and Britain closer together, and Germany left the meeting empty-handed.

The Moroccan crisis was something of a diplomatic revolution. Britain, France, Russia, and even the United States began to view Germany as a potential threat. At the same time, German leaders began to suspect sinister plots to encircle Germany and block its development as a world power. In 1907 Russia, battered by its disastrous war with Japan and the 1905 revolution, agreed to settle its territorial quarrels with Great Britain in Persia and Central Asia and signed the Anglo-Russian Agreement. This treaty, together with the earlier Franco-Russian Alliance of 1892 and Anglo-French Entente of 1904, served as a catalyst for the Triple Entente, the alliance of Great Britain, France, and Russia in the First World War (Map 28.1).

By 1909 Britain was psychologically, if not officially, in the Franco-Russian camp. Europe’s leading nations were divided into two hostile blocs, both ill-prepared to deal with upheaval in the Balkans.