Did Bismarck’s alliances keep the peace or cause WWI?

The short answer

• A new giant in the middle of Europe. The new Germany changed the scale of the European problem. Its population grew from about 41 million in 1871 to about 65 million by 1910, while France’s remained near 39 million. By 1913 it produced more than twice as much steel as Britain. The largest population west of Russia and Europe’s fastest-growing industry did not determine a particular alliance; they did require other powers to decide how to live beside a formidable neighbor. Bismarck’s system was one answer.
• Alsace-Lorraine and the French grievance. Germany’s victory brought unity at the price of a lasting French grievance. Under the Treaty of Frankfurt, France surrendered Alsace and most of Lorraine, with about 1.5 million inhabitants, and owed five billion francs in indemnity. It paid within three years, but could not recover the provinces. Their loss remained a wound in French politics, and Bismarck devoted twenty years to containing the hostility the victory had helped create.
• The Eastern Question. The Ottoman Empire had governed the Balkans for centuries. As it retreated, diplomats asked who would inherit its lands: this was the Eastern Question. Russia saw itself as protector of Orthodox Slavs and wanted free passage for its warships through the Straits. Austria-Hungary feared that strong Slav states on its border would unsettle Slavs within its own empire. Both were German partners, so each Balkan crisis threatened to set Bismarck’s allies against one another.
• The Kaiser’s new course. Wilhelm II became emperor in 1888 at twenty-nine and intended to rule in person. He forced Bismarck to resign in March 1890. His new chancellor, Leo von Caprivi, and foreign office adviser Friedrich von Holstein wanted simpler, more transparent commitments; they saw the Reinsurance Treaty as incompatible with the Austrian alliance. Dropping it made Germany’s policy easier to state, while removing a secret link that had discouraged Russia from seeking France. Within two years Bismarck’s system had ended.

What it changed

A war plan built on two fronts. The Franco-Russian alliance made a two-front war central to German planning. Alfred von Schlieffen’s answer, set out by 1905 and put into action in August 1914 (Chapter 4), was to defeat France first by sweeping through Belgium, then turn east before Russia’s slower mobilization was complete. The plan contemplated violating Belgian neutrality long before the crisis that brought war.

Britain bound by conversations. Britain had made no promise in the ententes to fight for France. But secret staff talks from 1906 and later naval arrangements gave both countries expectations about cooperation. When Britain went to war over Belgium in August 1914 (Chapter 3), its army already had plans to fight beside the French. The conversations had made intervention easier to imagine, even without a formal obligation.

A naval race that Germany lost. By 1912 the Royal Navy had concentrated its battleships in the North Sea, treating Germany as its most likely enemy. Tirpitz had wanted his fleet to win British respect; the result helped bring about the danger he hoped to deter. In the war (Chapter 8), the German High Seas Fleet was too small to win and too valuable to risk. It spent most of the war in harbor while Britain’s blockade strangled German trade.

Every crisis becomes a test of loyalty. A diplomatic setback could now be seen as a danger to an entire alliance. Germany failed to split the Entente at Tangier, and both sides drew the lesson that partners needed firmer support. Colonial and Balkan disputes became tests of loyalty. Chapter 2 follows three crises in six years and the lessons carried toward war.