On July 15, 1870, the French Empire mobilized its armed forces, and the following day, the North German Confederation—led by Prussia—followed suit. Once the Franco-Prussian War was declared, actual combat began with startling rapidity. The Prussians won a decisive victory at Sedan at the start of September, capturing French Emperor Napoleon III. Even so, the French managed a heroic second effort that kept the war going into 1871, but the Prussians still emerged victorious.

This short struggle killed some 200,000 people and involved more combatants on both sides than the recently concluded American Civil War, which had spanned four years. A somewhat larger number of people perished in the outbreaks of epidemic disease and internal political violence that surrounded the war.

At the time, the Franco-Prussian War was a shocking and apocalyptic global event. Today, it is largely forgotten in the English-speaking world, overshadowed by the far vaster struggles of the following century. We should not expect any explosion of commemoration on this 150th anniversary, but such neglect is badly mistaken. Without the war of 1870-71—without the political, military, and diplomatic revolutions that it launched—neither of the World Wars nor any later conflict can be properly understood. That Franco-Prussian War created a whole new European reality, with ramifications that spanned much of the globe. It echoed through the 20th century, and it still has potent lessons today.

Both France and Prussia were aggressive powers with potent military establishments and strong expansionist agendas. Since 1848, France had been ruled by Napoleon III, who took his imperial title in 1852. He enjoyed military glory for its own sake, but also found it a convenient way of diverting his subjects’ attention from internal economic stresses. Over the course of two decades, Napoleon intervened in Italy, defeating the Austrians; he challenged the Russians in the Crimea; and he threatened an invasion of England. Further afield, he built a vast tropical empire, even trying to draw Mexico into his sphere of influence.

above: French soldiers by a cannon during the Franco-Prussian War, July 23, 1870 (Wikimedia/public domain)Prussia, meanwhile, was expanding its control over the German-speaking states under the leadership of Chancellor Otto von Bismarck. Prussia defeated Denmark in 1864, and in 1866 Prussian forces bloodily evicted Habsburg power from the emerging German realm. Any thinking observer knew that Bismarck would soon move to integrate the remaining statelets of southern and western Germany, pushing directly against French interests. Historians still debate whether Bismarck cunningly lured Napoleon into declaring war in 1870, over a disputed succession to the Spanish throne, but sooner or later a conflict of some kind had to happen.

The war’s immediate consequences were far-reaching. Following the Prussian victory, Napoleon fled into exile in England, opening the way for a French Third Republic that persisted until 1940. On Jan. 18, 1871, Bismarck achieved his lifelong goal by proclaiming a new German Empire, a second Reich. Even more deliciously, he did so in the Hall of Mirrors at Versailles, the historic symbol of French political and cultural splendor. In March, triumphant Prussian legions paraded down the Champs-Élysées. German occupiers remained until the humiliated French paid off gargantuan war indemnities. Émile Zola’s classic novel about the French war effort and its outcome is aptly titled La Débâcle.

In broad outline, this story is familiar to anyone with a knowledge of European history, but some aspects of it must surprise. At least for Anglo-Americans, the common assumption is that Germany was the unquestioned aggressor, and that this was an early phase of a ruthless expansion that would resume in 1914, and again in 1939.

However, France at that time was a much stronger candidate for the role of historical bully. Since the mid-17th century, France had always been the strongest state of continental Europe, and French regimes had repeatedly tried to expand their borders to the Rhine, to include areas that we today think of as properly part of Belgium, the Netherlands, or western Germany. With varying degrees of determination, those French efforts involved some measure of cultural assimilation, and the imposition of the French language.

Particularly in the Napoleonic wars, French treatment of some German regions was brutal to the point of near-genocidal, with systematic plunder and starvation, and Prussians long remembered the occupation of 1806 as a singular horror. When victorious, the French stole local cultural treasures just as enthusiastically as the Nazis would during World War II. Adding to the sense of peril, before the Franco-Prussian War, nobody doubted that the French armed forces were by far Europe’s best-organized and most effective.

You may remember the scene in the 1942 film Casablanca, when German officers are singing their patriotic anthem “Die Wacht am Rhein” (“The Watch on the Rhine”) to the horror of the occupied French, who retaliate with a boisterous rendering of “La Marseillaise.” At that point, even non-Francophile Americans fight the temptation to stand and cheer. In the 20th century, “Die Wacht am Rhein” has rightly acquired a sinister reputation as a hymn of aggressive militarism: it is what the young soldiers sing when they march to war in the 1930 film All Quiet on the Western Front. But in its origins it reflects a very different world in which the Germans were the underdog defending their territory.


In 1840, even before the rise of the new Napoleon, French foreign minister Adolphe Thiers demanded that the Rhine be regarded as his country’s natural eastern border, with an implied threat of invasion and occupation. If implemented, that would have left Cologne, Bonn, Düsseldorf, and the then-emerging Ruhr region tenuously placed on the new borderlands, awaiting the next wave of French demands that would inevitably arise. Germans responded with horror and fear, but also with a brand new sense of national identity and patriotism. One manifestation of this was Die Wacht am Rhein, which promises that no foreigner will seize the river, and that patriots would maintain a faithful watch. It’s a brave song of stubborn, and probably futile, resistance against a far stronger aggressor.

The Franco-Prussian War decisively overturned that two-century-old assumption about French power and expansionism, and of German vulnerability. It was a radical transformation of geopolitical reality that took Europeans and Americans a generation to absorb fully. “This war represents the German revolution, a greater political event than the French Revolution of last century,” Benjamin Disraeli warned the British Parliament. “The balance of power has been entirely destroyed.”

Reading backwards from our stereotypes of 1940, we might expect the Prussian victory to have been a one-sided triumph based on overwhelming weaponry and determination, even a kind of proto-blitzkrieg. In a weighty piece of symbolism, the later German invaders in 1940 won a great victory at Sedan, the very scene of their victory over Napoleon III. Yet, actually, the two armies in the field in 1870 were well-matched, and the French scored some victories. The Prussians, on the other hand, took real risks, and the outcome of the war was not inevitable. At Gravelotte that August, the Prussians suffered 20,000 casualties in a single day, although they did secure a crucial strategic victory.

But on many key points, Prussian methods and innovations forged over the previous generation gave them an immense and war-winning advantage. As a result, the conflict launched a revolution in military affairs that dominated warfare until it was further revised by the horrific new insights of 1914.

Potentially, French forces should have outnumbered the Prussians on the battlefield. They forfeited that advantage because the Prussians were able to mobilize their troops more quickly. They had developed a wonderfully effective system of universal conscription and training that allowed them to organize and maintain their army in semipermanent readiness. After war was declared on July 16, Prussian invasion forces were already winning major victories on French soil by Aug. 4.

The Prussians were following carefully detailed plans drawn up by their General Staff, which was the first of its kind in the world. This was an organized unit of professional military leaders, constantly honed by annual war-games and maneuvers. It allowed Prussian armies to plan and execute large-scale encircling movements that swamped French foes. Prussian officers at all levels were trained in Auftragstaktik (mission tactics), emphasizing flexibility, creativity, and independence, allowing them to achieve mission goals without being coached on every stage of the process.

Prussians also excelled in applying new technologies, in which the French conspicuously lagged. The Prussians early learned the virtues of railroads in mobilizing and transporting armies, while telegraph systems allowed rapid communication. In modern jargon, the Prussians always held the advantage of command, control, and communication.

above: Anton von Werner’s 1894 painting Im Etappenquartier vor Paris (A Billet outside Paris) at the Alte Nationalgalerie, Berlin. The painting depicts German troops occupying the Château de Brunoy outside Paris on Oct. 24, 1870 during the Franco-Prussian War (Wikimedia/public domain)It was not that the French rejected technology as such—they even deployed the first machine gun prototypes, the mitrailleuse. But they never integrated new technologies as instinctively as did the Prussians. The gulf between the two sides was evident in artillery, which turned the balance in so many battles. Prussia’s Krupp cannon were better in every respect than anything the French had, more effective and with longer range, and the army deployed them offensively and accurately in direct support of infantry assaults. To their credit, the Prussians used their mighty artillery only sparingly to bombard stubborn Paris, as the high command thought that wholesale massacres of civilians would be unpardonable.

Prussian innovations in organization and technology radically changed the military world. Every other European power suddenly woke to find itself in a scramble to catch up to Prussia’s superiority.

Scarcely less significant than the war proper was its immediate aftermath, which brought outright social revolution in the form of the Paris Commune. Memories of that event shaped the history of the global left for the next century.

From September 1870 through January 1871, Paris suffered under a tight Prussian siege, which resulted in devastating hunger, deprivation, and disease. International media covered the situation breathlessly, with each day’s headlines assessing the city’s defenses and recording the new horrors. Seeing the obsessively detailed city maps that graced American front pages seemingly every day, Mark Twain offered his own absurd and satirical map of the “Fortifications of Paris,” which made about as much sense of the situation as any more sober endeavor. With Napoleon out of power, an emergency provisional government reconstituted itself as the embryonic Third Republic, with its capital at Tours, later Bordeaux, and ultimately Versailles.

That left Paris itself under the control of an increasingly radicalized socialist administration, with its military arm in the populist National Guard. Tensions grew under the new president, Adolphe Thiers, whom radicals denounced as a tool of the propertied classes: Karl Marx called him a “monstrous gnome.” In March 1871, the prospect of a government attack to reclaim Paris provoked a leftist coup.

The Commune held out for two months in increasingly desperate straits, with growing violence against the bourgeois and clergy, who found themselves hostages. Women militants were at the forefront of the movement, including the semi-mythical female arsonists, the Pétroleuses. When the city fell to Versailles government troops in May, the resulting purges and massacres claimed some twenty thousand lives, culminating in the atrocious Bloody Week. Tens of thousands of other Communards —as the Commune’s members were called—were imprisoned or transported.

In leftist memory, the Commune was the first modern example of a true revolutionary socialist administration, and as such, it represented a model for future action. In his very influential 1871 tract The Civil War in France, Marx declared that “Working men’s Paris, with its Commune, will be forever celebrated as the glorious harbinger of a new society.” In an ominous phrase, Friedrich Engels lauded the Commune as an exemplar of “the dictatorship of the proletariat.” Future revolutionary leaders like Lenin and Trotsky analyzed the Commune’s successes, and its reasons for failure. In more than one sense, Vladimir Lenin was a child of the crisis of 1870, the year of his birth: when he died in 1924, his body was wrapped in a Communard flag. Each new movement found its pattern in the Commune experience. Modern activists are as likely to vaunt its feminist heroines, like the legendary Red Virgin, Louise Michel, as its more mainstream figures.

Communists and anarchists alike drew savage lessons from the crisis, which seemingly taught the absolute bloody ruthlessness of the possessing classes when they faced a real threat from below. The Commune became a justification for overwhelming leftist violence in retaliation, for individual acts like assassination, for the formation of armed groups and militias, and—when power was achieved—for a state-imposed Red Terror. Memories of the Commune shaped the conduct of the Bolshevik Revolution and its European imitators after 1918, including the Spanish Republicans of the 1930s. Mao Zedong learned his own lessons, and cited the Paris precedent when launching the Chinese Cultural Revolution of the 1960s.

But the right, too, learned lessons, seeing an orgy of subversive violence made all the worse by the role of women insurgents. In 1871, The New York Times asserted that the Commune waged war “against civilization itself.” For a generation, governments responded to strikes or protests as if they were incipient signs of a new Paris Commune and reacted, or overreacted, accordingly. In the United States, Commune-related rhetoric was powerfully in evidence in the bitter conflicts of 1877, when great strikes in Pittsburgh and St. Louis were the tip of a very sizable iceberg of militant activism. Such French parallels immediately escalated the threat posed by the movement, leading authorities to see it in terms of outright insurgency, and to respond immediately with military force. One lasting consequence of the crisis was the total restructuring of the National Guard, to ensure that it could never become a subversive force on anything like the lines of its Paris namesake.

The Commune provided an object lesson in the class war, but it also reshaped European religion. Echoing the earlier French Revolution of the 1790s, the Communards persecuted and murdered Catholic clergy, most famous of whom was Archbishop of Paris Georges Darboy. Again, that set a precedent for future leftist regimes entranced by the Commune’s example, whether in Mexico, Russia, or Spain.

But the message for many Christians, and above all Catholics, was just as powerful, in suggesting the impossibility of reconciling socialism or secularism with religious faith. Commune memories became the ideological basis of Catholic politics of the most reactionary kind, which in France at least led to decades of frigid national polarization. Catholic grief and fury found material form in the towering Basilica of Sacré-Cœur, which was built to expiate the sins of the Commune, and to commemorate the martyrs.

Reinforcing those lessons were affairs in Italy. Before 1870, the newly formed Italian state dreamed of acquiring the city of Rome, where the Papacy survived under the protection of French arms. When the French garrison withdrew, Italy conquered the city and took it as the national capital, leaving the popes as effective prisoners in the Vatican until a new political accommodation could be worked out in 1929. Surrounded by secular and progressive Italy, the popes wrestled with how they might confront this threatening modernity. As in so much else, 1870 marks a pivot in European history, for conservatives as well as radicals.

The war’s consequences shaped European political life until World War I.

The assertion of German unity and pride was all the more stunning for a continent so long used to French glory, and the new Reich was born in something like a messianic atmosphere. Over the coming decades, Lutheran theologians in particular would combine vigorous nationalism with quite literal assertions that the new state was a portent of God’s kingdom on Earth. Had the empire not been born in the Miracle of 1870? Hyper-nationalist ideology shaped German political ambitions and planning into 1914 and beyond.

Over and above the fact of victory, the new German state exacted a heavy price from defeated France, annexing the provinces of Alsace and Lorraine. The determination to reclaim those lands, and to avenge defeat, became a national obsession, a fundamental ideology, which acquired the name of revanchisme (or revenge-ism).

That concept underlay much of French history over the following decades, occasionally bringing the country to the brink of a new civil war. At a time when the army was the sacred instrument of national revenge, the thought that a Jewish officer might betray its secrets to Germany was an ultimate blasphemy. The resulting affair of Captain Alfred Dreyfus in the 1890s further polarized the nation for a decade. It also taught Europe’s Jews that they would have to seek their fortune in a new land overseas, spurring the Zionist movement.

The central question in European life was when, not if, France would seek an apocalyptic settlement of its grievances, the still-open wounds left by the earlier conflict. World War I is inexplicable, except as the sequel to the Franco-Prussian War. That precedent also shaped expectations of the character and duration of the new struggle. When so many notoriously declared that World War I “will all be over by Christmas,” they were not being Pollyanna: they were just extrapolating from those dreadful months in 1870. Why should Round Two be any different?

One definition of revolution is a transformation so thorough that it becomes impossible even to imagine the world as it had existed before. Politically, that would certainly apply to the Franco-Prussian War. After 1871, all informed people knew that Germany was Europe’s overweening nation, an eternally aggressive bully, just as firmly as they had previously regarded France. In retrospect, it is difficult to recall just how recent that new reality was, although it has shaped political perceptions up to the present day.

That insight actually has political relevance today. When Americans look at their current global adversaries and rivals, we should never forget just how contingent and transient that enemy status might be. However bitter our foes might be in one generation, we have no eternal enemies—not Germany, not Russia, not China. One war, one revolutionary crisis, can overturn generations of assumptions and prejudices.