Part II: This essay is the second in our week-long series on geopolitics by Hal Brands, the Henry A. Kissinger Distinguished Professor of Global Affairs at the Johns Hopkins University and a senior fellow at the American Enterprise Institute. You can read part one here, part three here, part four here, and part five here.

When it was first delivered, in 1904, Mackinder’s pivot thesis was powerful but, mercifully, abstract. There had been consequential wars in living memory: the Crimean War, the wars of German unification, the Sino-Japanese war, and others. Yet it had been nearly a century since Napoleon’s defeat ended the last epic struggle for geopolitical dominance, a period of relative peace so long that many observers had come to see all-out great-power war as an absurdity.

That would change in 1914. The First World War was the first of the global conflicts that defined the Eurasian century. It offered a demonstration of how terrible and totalising such clashes could be.

A war that started in Sarajevo drew in countries on every inhabited continent. It led to carnage on a previously untold scale. The fighting eventually claimed 20 million lives and four empires; it triggered revolutions, anti-colonial revolts, and other political upheavals across the globe. The First World War, as Theodore Roosevelt put it, was a ‘great black tornado,’ which presaged even greater storms to follow.

The war certainly revealed the emerging geography of conflict in the Eurasian century. The First World War had many causes, but it was principally a fight over whether Germany could attain the sort of dual hegemony Mackinder had feared. That fight pitted unrivaled sea power against formidable land power; it had grave implications for the future of democracy, not just in Europe but also far beyond. The anti-German forces prevailed, but only narrowly, and only by summoning unprecedented transatlantic cooperation to preserve Eurasian equilibrium. The central truth the First World War revealed was that struggles for supremacy in Eurasia would inevitably go global — and that it would take the intervention of a distant power to keep the world in balance.

The King’s Gambit

Germany wasn’t the country that most worried Mackinder in 1904, but it should have been. After unification in 1871, Germany became an industrial dynamo and the dominant military power in continental Europe. Its hybrid political structure gave enormous authority in foreign affairs to a globally ambitious ruler — Kaiser Wilhelm II — and an offence-minded military elite. By the early 1900s, Germany was the epitome of a modern, illiberal state with the capacity — and geographic position — to expand deep into Eurasia’s core, toward its oceanic periphery, and far beyond.

It undoubtedly had the motivation. Before and during the First World War, German leaders envisioned controlling a sprawling Mitteleuropa — a sphere of economic and military influence running from the English Channel to Ukraine. Under Wilhelm II, Berlin simultaneously pursued a capacious ‘world policy,’ aimed at claiming a global empire; it began building a powerful battle-fleet meant to dissuade Britain from interfering. Ominously, German leaders suggested that coercion and violence might be the country’s means of geopolitical ascent. ‘The world is already partitioned,’ one foreign minister remarked. Germany’s expansion could only come at the expense of others.

For that reason, Germany’s rise polarised Europe’s politics. The two flanking powers, France and Russia, that were most threatened by German armies joined forces with the offshore power, Great Britain, that feared its growing navy. The Kaiser responded by relying more heavily on Austria-Hungary, while provoking a series of crises to test the resolve and unity of the Triple Entente. The result was mostly to harden alignments and raise the geopolitical stakes. Germany, British officials assessed, was likely aiming for a ‘general political hegemony and maritime ascendancy.’ German officials, for their part, embraced an expand-or-die mentality: ‘If Germany does not rule the world … it will disappear from the map.’

The First World War erupted when German officials began to fear the possibility of expansion was slipping away. By 1914, the strategic vise was tightening, as the Triple Entente ramped up its military efforts, on land and at sea, to outpace and contain Berlin. If Germany did not act quickly to cripple France and Russia, and to build the Continental empire that would allow it to compete globally with Britain, it might lose the chance forever. ‘I believe a war to be unavoidable,’ the chief of Germany’s general staff had declared in 1912: ‘the sooner the better.’

This was why Germany acted so belligerently following the assassination of the Austrian crown prince Franz Ferdinand in 1914 — by urging Austria-Hungary to attack Serbia even though this meant war with Russia, and then by striking France through Belgium despite knowing this could cause Britain to intervene. The First World War was a German preventive war, launched to win a hegemony that was becoming unattainable through peaceful means.

Unsafe for Democracy

Most leaders chose to fight in August 1914 expecting a short war. They got a long one instead. As the First World War unfolded across multiple theatres over multiple years, it illuminated several strategic patterns that students of Mackinder would have found familiar.

The first was that technology was indeed revolutionising geopolitics, by making struggles for primacy longer and more brutal. The emergence of modern states controlling industrialised economies gave leaders on both sides the ability to extract more money and manpower from their societies, and thus allowed the war to outlast all initial expectations. Technological advances such as the machine gun, poison gas, and submarines enabled industrial-scale slaughter and the crossing of new thresholds of terror. It seemed, said one British observer, that ‘all the resources of science had been called upon to perfect weapons of destruction for mankind.’

Second, the conflict pitted a land-based, aspiring hegemon against an amphibious counter-balancing coalition. Germany’s aims in the First World War were to push Russia out of Eastern Europe, claim strategic territory from the low countries and France, and thereby establish Continental dominance as well as a platform for imperial expansion and maritime supremacy. The members of the Triple Entente had widely varying objectives, but what united them was the fear that German ascendancy would destroy their own security. As British diplomat Eyre Crowe had warned in 1907, ‘The union of the greatest military with the greatest naval power in one state would compel the world to combine for the riddance of such an incubus.’

The strategies that both sides adopted reflected their comparative strengths and limitations. The Allies could not, until 1918, defeat German armies in Europe: They repeatedly tried and failed, at exorbitant cost. Yet they could, thanks to British sea power, sweep Germany’s commerce from the oceans, bottle up its surface fleet, and enact a punishing blockade. The Royal Navy could also patrol vital lifelines, from Britain to France and America to Britain, that kept the coalition fighting, while the Allies probed around the periphery in hopes of turning a flank.

Germany, by contrast, held the advantage almost everywhere its peerless armies could reach. Even so, it could not force a decision because two of its key enemies were at least partially beyond that reach—Britain because of its sea channel and its navy, Russia because of its great strategic depth. So the Germans, too, pursued indirect strategies: Using Vladimir Lenin and the Bolsheviks to wage political warfare against the tsarist regime, employing submarine warfare to menace the oceanic links that sustained the Allies. Winning a war for geopolitical primacy, German officials understood, required fracturing the counter-hegemonic coalition.

Third, these strategies ensured that a Eurasian war became a global conflagration. In 1914, a dispute in the Balkans had drawn in most of Europe’s major powers, with the rest to follow. The clash between empires, in turn, inevitably spilled into the Middle East, Africa, and even the Pacific. Soon the United States was the only major power not at war, although it was deeply involved in its role as the Allies’ supplier and banker. And America, too, entered the fighting in 1917, because a German victory would endanger freedom of the seas in the Atlantic and perhaps the security of the Western hemisphere. ‘Here was the proof,’ writes historian John Darwin, ‘that, with a world economy and a single system of world politics, there was no escape from the fallout of the war, wherever it started.’

This was especially so because of a final issue — that the ideological dimensions of the conflict sharpened over time. The Russian revolution allowed Woodrow Wilson to claim that America was fighting for freedom and not for the aggrandisement of an absolute monarchy. Meanwhile, Germany slid more deeply into military dictatorship and racialised ideology. Fundamentally, though, the ideological stakes became clearer because the war highlighted that the flourishing of democracy anywhere required denying aggressive autocracies a dominant position at the heart of the international system.

A German victory, Walter Lippmann later wrote, would have forced even the United States to militarise its economy and society as the price of security: It would ‘have made the world unsafe for the American democracies from Canada to the Argentine.’ What was ultimately at stake in the First World War — and in the Eurasian century — was the fate of freedom around the world.

Why Germany Lost

It is tempting to see the outcome of the war as a foregone conclusion: How could Germany ever have defeated a pack of enemies that effectively had it surrounded? Indeed, Germany’s place at the centre of Europe forced it into a series of desperate wartime gambles, each of which worsened its basic predicament.

The Schlieffen Plan for a lighting offensive through Belgium was meant to solve the problem of a two-front war by defeating France quickly, but guaranteed the enmity of Britain. The effort to starve out Britain through unrestricted submarine warfare triggered conflict with America. The resulting bid to win the war decisively in the West, before America could fully mobilise, bled the German army white. From this perspective, Germany’s geographic position was not an advantage but an inescapable deathtrap.

Yet there is a certain hindsight bias at work here, for a German victory didn’t seem outlandish at the time. After all, Germany almost won the war in the West twice, in 1914 and again in 1918, with offensives that nearly reached Paris. Impending bankruptcy and the submarine offensive nearly broke Britain; by 1917, a mutinous French army verged on collapse. Most important, the Germans did achieve a crushing victory in the East, stripping Russia of most of its coal and production and industry, slicing off huge chunks of its land and population, turning most of Eastern Europe and the Caucasus into a German sphere of influence, and thereby opening the door, if only temporarily, to a fundamental strategic transformation of Eurasia.

Germany fared so well by exploiting the very features Mackinder had anticipated. An autocratic state harnessed German economy and society for something approaching ‘total war’ by 1918. An efficient German military outfought all comers tactically; a sophisticated economy compensated for the blockade through rationing and use of synthetic products.

Germany’s geography also conveyed powerful advantages. Its central position and highly developed railways allowed it to compensate for numerical inferiority by rapidly shuttling forces between theatres — and once, to move a full army from front to front within a week.  Meanwhile, Berlin mostly shrugged off the effect of peripheral operations, and it exploited open space on the Eastern front to wage a devastating war of manoeuvre against Russian forces. In short, Germany’s experience showed how a modern, centrally located autocracy could hold the world at bay and even come perilously close to victory.

The lasting lesson of the First World War, in fact, was that it required a global response to defeat a capable Eurasian challenger. American financial and industrial strength bolstered the Allies throughout the conflict. American entry into a war that the Allies were gradually losing forced Germany to go for broke in the West in 1918 rather than wait to consolidate its gains in the East. The arrival of American forces tipped the balance that summer, when Allied armies were again near breaking. We often think of the First World War as a European war. But what clinched that conflict for the Allies was the formation of a transatlantic coalition dedicated to beating back Eurasian aggressors.

From One War to Another

Mackinder recognized as much after the war, when he revisited his original thesis in a book called Democratic Ideals and Reality. ‘We have conquered,’ he wrote, but had Germany conquered it would have dominated the vast ‘world island’ and perhaps the oceans beyond. Even had Germany simply gained time to exploit the resources of Eastern Europe, it would have dramatically reordered the strategic landscape. ‘Ought we not to recognize that that is the great ultimate threat to the world’s liberty,’ Mackinder asked, ‘and to provide against it in our new political system?’

It was the right question, yet an effective answer proved elusive. The central problem of twentieth-century geopolitics was that the world’s decisive strategic theatre — Eurasia — was no longer capable of keeping itself in balance. That equilibrium could be preserved only with decisive contributions from the country, America, that had become preeminent on its own continent and thereby gained the freedom to influence events around the globe.

Yet herein lay the crippling weakness of the postwar system. Because America was located so far from the front lines, its strategic instinct was to remain aloof from Eurasian geopolitics until pressing threats emerged, and then to wait — as it had in the First World War — until the situation turned critical before throwing its power into the scales. This was precisely what caused the United States to retreat, strategically, from a devastated Europe after the First World War— and then to find itself, and all of humanity, facing an even more vicious challenge a generation later.