etween 1914 and 1918, Europe’s great powers waged a war unprecedented in its scale and horror. “Europe,” Winston Churchill wrote, “became one vast battlefield on which after years of struggle not armies but nations broke and ran.” More than ten million soldiers died. Civilian deaths exceeded five million. Four empires collapsed. George F. Kennan called it the “seminal catastrophe” of the twentieth century.

In 1919, as the peacemakers at Versailles were constructing a new world order in the wake of WWI, a relatively unknown British geographer and Member of Parliament cautioned the democratic statesmen to adjust their ideals to the “lasting realities of our earthly home.”

“Our memories,” began Halford Mackinder in Democratic Ideals and Reality, “are still full of the vivid detail of an all-absorbing warfare…. The last four years…have been the outcome of one century and the prelude to another.” The Versailles peacemakers promised an end to war, with future international disputes settled by a League of Nations. “But,” Mackinder warned, “international tension will accumulate again, though slowly at first.”

Mackinder’s perspective was geo-historical:

The great wars of history…are the outcome…of the unequal growth of nations, and that unequal growth is not wholly due to the greater genius and energy of some nations as compared with others; in large measure it is the result of the uneven distribution of fertility and strategical opportunity upon the face of the globe. In other words, there is in nature no such thing as equality of opportunity for the nations. [T]he grouping of lands and seas, and of fertility and natural pathways, is such as to lend itself to the growth of empires, and in the end of a single world empire.

Born in 1861 in Gainsborough, England, Mackinder studied at Epsom College and Christ Church, Oxford, and helped found Oxford’s school of geography.  Understanding geographical causation in history, he believed, could help statesmen glimpse the future. He praised statesmen who possessed “geographical capacity,” defined as a “mind which flits easily over the globe, which thinks in terms of the map, which quickly clothes the map with meaning, which correctly and intuitively places the commercial, historical, or political drama on its stage.” World history’s greatest events, he wrote, were causally related to “the greatest features of geography.”

In 1904, Mackinder delivered a paper entitled “The Geographical Pivot of History” to the Royal Geographical Society. There, Mackinder presented a breathtaking geopolitical survey of world history.  The great discoveries of the “Columbian epoch” had ended; “the outline of the map of the world has been completed with approximate accuracy.” The world was now a “closed political system” where “[e]very explosion of social forces, instead of being dissipated in a surrounding circuit of unknown space and barbaric chaos, will be sharply re-echoed from the far side of the globe, and weak elements in the political and economic organism of the world will be shattered in consequence.”

Eurasia is the “great continent,” containing most of the world’s people and resources. Eurasia’s northern-central core is the “pivot region,” its geography highly suitable to mobile land power and impenetrable to sea power. Eurasia’s highly populated areas abutting the pivot region, and with access to the sea, occupy the “inner or marginal crescent.” Great Britain, Japan, Australia, coastal southern Africa, and North and South America are located in an “outer or insular crescent.”

Historically, the pivot region hosted a series of nomadic land powers that launched repeated invasions of Western Europe, Southwest Asia, and East Asia. Especially noteworthy were the Mongol incursions into the marginal crescent between the 13^th and 15^th centuries. “[A]ll the settled margins of the Old World,” Mackinder writes, “sooner or later felt the expansive force of mobile power originating in the [Eurasian] steppe. Russia, Persia, India, and China were either made tributary, or received Mongol dynasties.” During that same period and beyond “the great mariners of the Columbian generation” enveloped Eurasia and set the stage for repeated clashes between maritime and land powers for predominance in Eurasia.

Mackinder warned that if a great power, controlling the pivot region, could expand over the “marginal lands” of Eurasia and use the continent’s resources to build a powerful navy, “the empire of the world would then be in sight.” The balance of power depended on “the relative number, virility, equipment, and organization of the competing peoples.”

Peace, Mackinder noted in Democratic Ideals and Reality, requires that statesmen navigate among the competing worldviews of idealists (who look to the rights of man), organizers (who value efficient resource use), and realists (who never forget man’s fallen nature).

The paradigmatic realist was German Chancellor Otto von Bismarck, who Mackinder praised for his ability to adjust war to policy. Mackinder most admired Bismarck’s ability to understand the minds of other nations.

Mackinder criticized idealists for being fierce moralists. They “lay down on paper good principles of conduct,” but refuse “to reckon with the realities of geography and economics.” Democracies are especially prone to rule by moralists—like Woodrow Wilson—who refuse to think strategically until war is imminent. Mackinder chided the democratic statesmen who, at WWI’s end, cheered the fall of Russian autocracy even as the revolution veered toward totalitarianism. During Russia’s Civil War, Mackinder served as Britain’s ambassador to the White forces, who were battling Bolsheviks in southern Russia. He urged Britain’s leaders to crush Bolshevism before it consolidated power and threatened the world’s democracies. No one, except for Winston Churchill, sympathized with Mackinder’s view of Lenin’s regime.

Mackinder has been mischaracterized as an exponent of the primacy of land power over sea power in international competition. In truth, he saw that land power and sea power were in some respects complementary:

What if the Great Continent, the whole World-Island or a large part of it, were at some future time to become a single and untied base of sea-power? Would not the other insular bases be outbuilt as regards ships and outmanned as regards seamen? Their fleets would no doubt fight with all the heroism begotten of their histories, but the end would be fated.

“If we take the long view,” he continued, “must we not still reckon with the possibility that a large part of the Great Continent might some day be united under a single sway, and that an invincible sea-power might be based upon it?” This, he wrote, was “the great ultimate threat to the world’s liberty.”  

The most strategically significant region of the Great Continent was the northern-central core of Eurasia, which he called the “Heartland.” Throughout history mobile hordes (Huns, Magyars, Turks, Avars, and Mongols) originating in the Heartland fell “like a devastating avalanche” upon Europe and China.

The Heartland hosted a sufficient population “to threaten the liberty of the world from within this citadel of the World-Island.” This was the geopolitical reality that trumped the idealistic notions of the democratic statesmen at Versailles. “No mere scraps of paper,” he wrote, “even though they be the written constitution of a League of Nations, are, under the conditions of to-day, a sufficient guarantee that the Heartland will not again become the center of a world war.”

In the First World War Germany defeated Russia, while Britain and France “had to call in the help of America”—without which they “would not have been able to reverse the decision in the East.” Germany’s mistake was attacking France before effectively organizing the resources of Eastern Europe and the Heartland. “Had Germany elected to stand on the defensive on her short frontier towards France,” he wrote, “and had she thrown her main strength against Russia, it is not improbable that the world would …overshadowed by a German East Europe in command of all the Heartland.”

Mackinder suggested that the democracies construct a geopolitical balance of power based on the following dictum: “Who rules East Europe commands the Heartland: Who rules the Heartland commands the World-Island: Who rules the World-Island commands the World.” Unless they erected a sufficient bulwark between Germany and Russia, he predicted, “our descendants will find themselves under the necessity of marshaling their power afresh for the siege of the Heartland.” Mackinder doubted Germany’s defeat would alter its ambitions. “He would be a sanguine man,” he wrote, “who would trust the future peace of the world to a change in the mentality of any nation.” Mackinder’s solution was to erect a “tier of independent states” in Central Europe supported by “the outer nations” of Britain, France and America. The Western democracies must also “protect the Indians and Chinese from Heartland conquest.”

The Treaty of Versailles established a tier of independent states in Eastern Europe, but did not formalize their support by “outer nations.” Democratic Ideals and Reality mostly collected dust on bookshelves until events confirmed its wisdom and prescience.  

One hundred years after Democratic Ideals and Reality was published, the world order is challenged by a rising China and a rejuvenated Russia. Eurasia is still the Great Continent, and its control by a hostile power or alliance of powers would threaten the security of the United States. It would behoove our nation’s political and military leaders to re-read Mackinder’s timeless classic.