http://www.chroniclesmagazine.org/2014/April/38/4/magazine/article/13654
In April 1904, Scottish geographer Halford Mackinder gave a lecture at the Royal Geographical Society. His paper, “The Geographical Pivot of History,” caused a sensation and marked the birth of geopolitics as an autonomous discipline. According to Mackinder, control over the Eurasian “World-Island” is the key to global hegemony. At its core is the “pivot area,” the Heartland, which extends from the Volga to the Yangtze and from the Himalayas to the Arctic. “My concern is with the general physical control, rather than the causes of universal history,” Mackinder declared.
At the end of the Great War, profoundly concerned with what he saw as the need for an effective barrier of nations between Germany and Russia, Mackinder summarized his theory as follows:
Who rules East Europe commands the Heartland;
Who rules the Heartland commands the World-Island;
Who rules the World-Island controls the world.
This dictum helps explain the essence of the Ukrainian crisis, as well as the motivation behind the continuing ambition of some U.S. policymakers to expand NATO eastward.
The model has undergone several modifications since Mackinder. In his 1942 book America’s Strategy in World Politics, Nicholas Spykman sought to “develop a grand strategy for both war and peace based on the implications of its geographic location in the world.” In the 19th century, he wrote, Russian pressure from the “heartland” was countered by British naval power in the “great game,” and it was America’s destiny to take over that role once World War II was over. Six months before the Battle of Stalingrad Spykman wrote that a “Russian state from the Urals to the North Sea can be no great improvement over a German state from the North Sea to the Urals.” For Spykman the key region of world politics was the coastal region bordering the “Heartland,” which he called the “rimland.” He changed Mackinder’s formula accordingly: “Who controls the rimland rules Eurasia; who rules Eurasia controls the destinies of the world.”
Spykman died in 1943, but his ideas were reflected four years later in Harry Truman’s strategy of containment. Holding on to the rimland, from Norway across Central Europe to Greece and Turkey, was the mainstay of America’s Cold War strategy and the rationale behind the creation of NATO in 1949. Containment swiftly turned into a massive rollback, however, when the Soviet Union disintegrated. In 1996 Bill Clinton violated the commitment against NATO expansion made by his predecessor, and the alliance reached Russia’s czarist borders. In 2004 it expanded almost to the suburbs of St. Petersburg with the inclusion of the three Baltic republics. All along Ukraine had remained the glittering prize, however, the key to limiting Russia’s access to the Black Sea, and a potential geostrategic knife in southern Russia’s soft underbelly.