IF the United States stumbles into the “Thucydides trap” this late in the “great game” and drags China along with it, the outcome would be decided a great deal by geography. Sir Halford Mackinder, considered the father of geopolitics, theorized early in the 20th century: “Who rules East Europe commands the Heartland; who rules the Heartland commands the World-Island; who rules the World-Island commands the world.” (Mackinder, Democratic Ideals and Reality, p. 150)

Here, the “heartland” refers to the vast plains in central Eurasia bounded by the Volga River in the west, the Himalayan mountains and the mountain ranges of Afghanistan and Iran in the south, the Gobi and Taklimakan deserts in the east, and the Arctic region in the north. The “world island,” on the other hand, refers to the three continents of Asia, Europe and Africa taken as one contiguous island. These natural barriers serve as fortress walls protecting the expansive plains in the middle, known as the heartland.