Bismarck gained control of Prussia in 1862 and immediately set upon unifying the German confederation with a policy of ‘iron and blood’. Perhaps the most skillful practitioner of realpolitik in history, he joined forces with Austria to defeat Denmark in 1864, and with Italy in 1866 to defeat Austria. In 1870, he dealt France a humiliating defeat and annexed Alsace and Lorraine. He became Chancellor soon after and remained in office till 1890. In the Bismarkian era, Germany was the most powerful state on the continent. Yet, Bismarck strove to maintain – not alter – the balance of power in Europe. Why?
The reason is simple: Germany was surrounded by great powers, Russia and Austria-Hungary to the east, and France to the West. If he had tried to annex additional territory, Bismarck would have to invade either France or Russia. Germany would end up fighting against both, and maybe even Great Britain, in a two-front war. This became clear during the “War in Sight Crisis” in 1875, when Great Britain and Russia declared that they would not allow Germany to crush France, as they had done in 1870. Germany wasn’t strong enough to fight all three at once. Yet.
By the turn of the century, Germany had grown much stronger. It had surpassed Great Britain in wealth and industrial production. It’s military had grown much more powerful than its continental rivals taken together. According to plausible numerical estimates of relative power, it could defeat both its continental rivals together by 1905, but not if it also had to fight Great Britain.
In 1897, Germany initiated a naval arms race with Great Britain and embarked upon a diplomatic strategy of controlled coercion and brinksmanship called Weltpolitik. This was a strategy of calculated risk, using the threat of war to gain unilateral advantages. The principal tool of this nuanced strategy was necessarily the navy – the army being a very inflexible tool – making this a sort of gunboat diplomacy. The coercive diplomacy of Wilhelmine Germany and its increasing power led to the formation of an alliance between France and Great Britain, the Entente cordiale, signed in 1904.
In 1905, Germany initiated a major diplomatic crisis with France over Morocco, which had come under French protection the year before with acquiescence of Great Britain and Spain. That March, the Kaiser landed in Tangier and declared support for Moroccan independence. Germany wanted to bring Morocco under its protection so that it would gain control of the strategic choke-point of the Strait of Gibraltar thereby challenging British naval might in the Western Mediterranean. The crisis nearly precipitated a continental war. It was at this critical juncture that the Kaiser asked his Chief of General Staff since 1891, Field Marshal Alfred von Schlieffen, to present to him a war plan. The German General Staff’s principal preoccupation was drawing up war plans, and Schlieffen had been working on his masterpiece for a decade. His plan capitalized on three key vulnerabilities of Germany’s rivals.
First, Russia’s inability to mobilize its army rapidly. Due to its vast size and underdeveloped roads, Russia could not bring its full weight to bear until the second month of the campaign. This left the weaker France exposed to a quick military defeat. Second, Belgium had no permanent defenses at the critical railway junction at Liège. The German General Staff hoped to take Liège with its tunnels and bridges intact by invading quickly. Third, British intentions to intervene in a continental war to aid France were uncertain. Schlieffen did not bank on British neutrality. Indeed, he assumed that Britain would eventually dispatch the British Expeditionary Force to protect France. The critical question was how to delay the British decision enough to allow the German army to knock France out of the war.
French defenses along Alsace-Lorraine were strong and the French plan – which was also offensive – was to attack there. The Schlieffen plan was therefore designed as an enveloping attack on the French flanks. The plan called for a defensive posture – indeed to allow the French offensive to gain ground – along the Franco-German border. The subtlety of the German offense on the Western front was that “it would operate like a revolving door – the harder the French pushed on one side, the more sharply would the other swing around and strike their back.” Schlieffen expected the German army to crush the French army in under a month and take Paris. A majority of the divisions would then board the train to the eastern front to face the Russian army. The eastern campaign was expected to last much longer due to the infinite ability of the Russian army to withdraw into the vastness of Russia and evade battle. This is why the campaign on the Western front had to take place first.
At the time of the Moroccan crisis, the Russian army was in fact getting pummeled by the Japanese in Manchuria, and the Czar was facing an intensifying revolutionary unrest at home. By the fall of 1905, the Russian armed forces had been conclusively defeated in the first modern great power conflict, and the domestic political situation in Russia had become highly unstable. The German General Staff was therefore well aware that Russia was out of business for the time being. Here was a remarkable opportunity to crush France and establish German military hegemony in Europe.
It is no exaggeration to say that had the Schlieffen plan been implemented at this point, Germany would’ve emerged as the world’s first superpower. It would’ve redrawn the map of Europe and ensured German supremacy on the continent for the foreseeable future. In every single indicator of latent power – territory, population, wealth, and industrial potential – it would’ve rivaled or surpassed the United States. The German position on the continent would’ve been well nigh impregnable and the British would have to accept the fait accompli. In a matter of years, the German navy would’ve become more powerful than the Royal navy, but the eclipse of Britain as the leading global power would’ve been immediate. Had the Germans moved in for the kill at this opportune moment, there is hardly a doubt that this century would’ve been Germany’s. Furthermore, the world would’ve been spared two World Wars and Germany’s descent into the barbarism of the Third Reich.
John J. Mearsheimer takes this to be the single most important counter-example to his theory of offensive realism, which posits that great powers will use every possible tool to maximize their power – including war and conquest – because this is the best way to achieve security. “Here was an excellent opportunity for Germany to crush France and take a giant step toward achieving hegemony in Europe. It surely made more sense for Germany to go to war in 1905 than in 1914. But Germany did not even seriously consider going to war in 1905, which contradicts what offensive realism would predict.” The possibility was, in fact, raised by German Generals, but not seriously considered by the Kaiser. Even Schlieffen seems to have thought it too soon. It would make a fascinating question for micro-historical research: what were they thinking?
 William B. Moul. Review of International Studies , Vol. 15, No. 2, Special Issue on the Balance of Power (Apr., 1989), pp. 101-121
His index is just the arithmetic mean of the relative shares of pig iron production, steel production, energy consumption, number of military personnel, and military expenditures.
 Mearsheimer, John J. The Tragedy of Great Power Politics. New York: Norton, 2001. Print.