The Franco-Prussian War 150 years on: A conflict that shaped the modern state

In his seminal work, The Franco-Prussian War: The German Invasion of France, 1870–1871, published in 1961, historian Sir Michael Howard revitalised military history scholarship. He looked beyond campaigns and battles to see instead how the societies of the belligerent states shaped the armies fighting on their behalf, and in many ways determined the outcomes of those conflicts.

Populist disruptors and the path to conflict

Looking back at the pre-war 1870 landscape, there are parallels that can be drawn today, including notably the role of populist disruptors in triggering international conflict. Emperor Napoleon III of France and Prussia's Otto von Bismarck were both products of the 1848 revolutions and master media manipulators who exploited the power of nationalism. Napoleon did so first, sweeping to power in the December 1848 presidential elections on the promise of ‘making France great again’, as it had been under his uncle, the first Napoleon. Four years later, just before his original term should have expired, he made himself emperor, and quickly reasserted French prestige by launching a succession of wars, including against Russia in the Crimea (1853-56).

Napoleon III's wars had unintended outcomes. One of these was that they turned Russia from being a bastion of the international order into a revisionist power. This in turn gave space to Bismarck to wreck what remained of the European system in a way that was definitely not to France's advantage. Austria was the main victim initially in the shake-up that followed, losing its position in Italy following military defeat at the hands of France in 1859, and more spectacularly forfeiting its prime role in Germany to Prussia after defeat in 1866.

This set the scene for the 1870 Franco-Prussian war. France, determined to thwart Prussia’s further rise, sought to block the candidacy of a Prussian prince to the Spanish throne in what looked like a good, old-fashioned, dynastic succession crisis. What made things different from earlier centuries was the weight of public opinion, in an age of universal male suffrage. Policy makers in Berlin and Paris sought to exploit the rising tide of nationalism on both sides of the Rhine, and this increased the risk of an explosion. That explosion came on 19 July.

A rapid French rout

Experts at the time expected the French to win. They overlooked serious weaknesses on the French side, which Sir Michael Howard's analysis shows extended far beyond the narrow military field, to wider political and societal disadvantages. These were reflected above all in the French conscription system, inherited in its essentials from the first Napoleon. This imposed upon the male population an obligation to serve, but in practice, only a small fraction was ever called up, who then served for seven years and often more. In consequence, the French army lacked the ability to 'scale-up' by calling on a mass of reservists.

The Prussian army, in contrast, drew upon the entire male population, producing a substantial body of trained reservists upon mobilisation. Prussian military planning, conducted by the famed General Staff headed by Helmuth von Moltke, made best use of the resulting numerical advantage, not least through the clever exploitation of railways.

Many military observers nonetheless preferred the French system, which produced an essentially professional force that was far better-suited to the near-continuous overseas deployments that Napoleon III's global ambitions demanded. Most damaging of all, despite its elitist pretensions, the French army was socially rather low-status. This was because the rich were allowed to pay for replacements to serve instead of their sons, should they be unlucky enough to be called up. No such facility existed in Prussia, with the result that its army more fairly approximated the nation-in-arms.

The consequence in 1870 was a French rout. General Philip Sheridan, American Civil War veteran, observed the Franco-German conflict at first hand, and his summary of the reasons for the outcome can hardly be bettered:

The French never recovered from the swift Prussian mobilisation, which included the direction of vast forces by rail towards and then across the frontier before the other side could adequately respond. Political reasons on the French side precluded the option of trading space for time, with the result that successive French armies were pushed forward into a series of encirclements and defeats. The most famous of these, the Battle of Sedan (1-2 September), cost Napoleon III his throne.

Sedan became something of a symbolic, foundational moment in the creation of the new German Empire that soon followed. Indeed, Sedantag (or 'Sedan Day'), became an unofficial holiday for the new nation state. This conveniently overlooked the far lengthier, messier and bloodier post-Sedan phase of the War, that ended only with the ceasefire at the end of January 1871. Features of this second phase included the German siege of Paris, efforts by French irregulars known as Francs-tireurs to disrupt Moltke's supply lines, and a brutal counter-insurgency campaign to stop them. Yet, as Sheridan noted, this form of resistance on the French side could only delay, not prevent, the final outcome.

A war that shaped the modern state

Geo-politically the outcome of the Franco-Prussian War was massive. It led directly to the creation of the German Empire, Continental Europe's most powerful state with Berlin replacing Paris as the focal point of global politics.

In the military domain, several lessons were learned. The first was the advantage of a system of conscription that was genuinely universal, for men, and that produced a large pool of reservists. The second was the importance of fast mobilisation, and planning to insure that the vast forces now available arrived at the right point, at the right time. The stress on swift mobilisation that was baked into war plans not only in Germany, but in other states too, made it far more likely that a future international crisis would trigger a war. This would prove to be the case in July 1914.

A third was the devastating impact of modern weapons, like the French Chassepot breach-loading rifle, and the Prussian steel breach-loading field guns. These weapons made frontal assaults by large densely-packed formations of infantry and heavy cavalry ill-advised. Battlefield tactics needed to adapt accordingly, with much more emphasis on smaller formations, flanking movements, and the use of cover. These tactics in turn required more initiative from junior and non-commissioned officers, and also ordinary soldiers.

The implication of this last point in particular extended well beyond the narrowly military domain. Instead, it had implications for wider policy, notably in areas concerned with education and public health. Policy makers recognised that the efficiency of armies was intimately bound up with the educational ability not only of a small elite, but of the entire population. France in particular drew the lesson from 1870 that Prussia won because of its better school system, and acted accordingly, passing the so-called Jules Ferry Laws in the 1880s instituting free, mandatory and secular education for children. Meanwhile, on the other side of the Rhine, the newly-minted German Empire was putting in place the world’s first government-mandated welfare system.

It is fitting to conclude this short piece by referring again to Sir Michael Howard’s work on the Franco-Prussian War. This conflict in particular lent itself to a comparative study of the societal differences between the two belligerents, France and Germany. These differences not only largely determined the military outcome, but also informed how the two sides learned the lessons of the war subsequently. This process, as already noted, hastened state building in Europe and beyond; and, as a later legacy, it helped shape the modern discipline of military history itself.