In 1904, British geographer Halford J. Mackinder presented a landmark paper, “The Geographical Pivot of History,” to the Royal Geographic Society of London. In this and subsequent writings, Mackinder argued that changes in technology—especially the revolution in land transportation brought about by the railroad, the internal combustion engine, and the construction of a modern highway and road network—had altered the relationship between sea and land power, bringing the Columbian age of dominant sea power to a close. In this new, tightly connected global system, land power would hold the advantage. The center of emerging land power was the Eurasian core area—the geographical pivot, roughly coincident with the tsarist Russian empire—that Mackinder would come to call the Heartland. This core area was inaccessible to sea power and therefore was capable of being exploited by a land power seeking to dominate the Eurasian “World-Island” from its continental fortress. Surrounding the Heartland were two crescents: first, a wholly maritime outer crescent consisting of the Americas, the British Isles, Australia, and sub-Saharan Africa; and second, an inner crescent (partly maritime, partly continental) that extended along the Eurasian littoral, including most of continental Europe west of Russia, the Maghreb, the Middle East, and continental South, Southeast, and East Asia. Most of the world’s population, and its great civilizations, inhabited this crescent.
Because of its location, Mackinder believed that the inner crescent would be a permanent zone of conflict. If a land power expanded over these marginal areas of Europe and Asia, it would obtain vast resources for building a naval fleet capable of overwhelming the outer crescent, the ring of islands and outer continents that surrounded the World Island. World empire would then be in sight. They key to world politics in the early 20th century, as Mackinder saw it, was the struggle between Russia and Germany for control of the Heartland and adjacent areas, especially Eastern Europe. For Mackinder, Eastern Europe was the gateway to and from the Heartland, which later led him to offer his famous formulation.
Who rules Eastern Europe commands the Heartland
Who rules the Heartland commands the World-Island
Who rules the World-Island commands the world
Mackinder revised his geographical definition of the Heartland several times over the next few decades. To reflect on the lessons and consequences of World War I, he published a collection of his major essays on geopolitics (a term he disliked), entitled Democratic Ideals and Reality. He later raised the possibility that the Heartland could be balanced by the powers of what he called the “Midland Basin”—Western Europe and North America—the countries that surrounded the “Midland Ocean.” Mackinder’s conception of security influenced the negotiators at Versailles in 1919, the debate over British strategy in the inter-war years, and the American policy of containing the Soviet Union during the Cold War.