Last March retired U.S. Pacific Fleet commander Patrick Walsh gave an interview with Asahi Shimbun in which he likened the South China Sea to a new “strategic pivot”—nooooo, not the pivot word again!—in the Asia-Pacific region. Admiral Walsh summoned up the ghost of land-power theorist Sir Halford Mackinder to illustrate his analogy. Mackinder was a founding father of geopolitics and a foil for Alfred Thayer Mahan. In an indirect riposte to Mahan’s thesis that command of the sea was a decisive force in history, Mackinder summarized his argument (in 1919) thus: “Who rules East Europe commands the Heartland: Who rules the Heartland commands the World-Island: Who rules the World-Island commands the World.”

Bracing stuff. Eurasia was the World-Island in Mackinder’s lexicon, while the Heartland lay in Central Asia. It was the “geographic pivot of history,” to borrow the title of his famous 1904 essay. The great power that held sway over the region could exploit its “interior lines,” along with rapid advances in land transportation—mainly railroads—to move forces about more nimbly than navies could around the periphery. Their geographic positions situated Russia and Germany for struggle over the Heartland. Mackinder thus foreshadowed the bloodlettings of the world wars.

Walsh’s thesis is intriguing. Some thoughts about the geopolitics of Southeast Asia, though. Is the South China Sea really a watery Heartland (Heartsea?) from which a dominant power can rule the rule the World-Ocean—presumably the combined Pacific and Indian oceans—and thence the world? This seems a bit much. It certainly occupies a central position at the juncture between the two oceans. The power that commanded South China Sea waters and skies, and could exclude rivals, would enjoy the advantage of easy, relatively economical strategic mobility. It could move forces to and fro from southeast to northeast, or into the broad Pacific. Thus far the analogy to the Heartland holds up. Interior lines work.

On the other hand, there exists an exterior line of communication by which mariners and airmen can bypass the South China Sea. Ships and planes could pass between northern Australia and the Indonesian archipelago, avoiding a central power that ruled Southeast Asia. It would have been far harder to circumvent Mackinder’s Heartland, bounded as it was by the Himalayas and Hindu Kush to the south. There’s also the small problem that the power that commanded the Heartland—Russia, then the Soviet Union—ended up ruling neither all of Eurasia nor the world. Central Asia was a central position, but it proved harder than Mackinder foresaw to harness it effectively. In this sense the South China Sea, which is heavily populated, rich in resources and commerce, and home to well-trafficked shipping routes, may actually be a better Heartland than the arid one that captured Mackinder’s imagination.

Admiral Walsh may have conjured up Mackinder to make a point about how the Heartland thesis influenced strategists a century ago. Those who subscribed to the idea of a geographic pivot were apt to attach inordinate value to controlling Central Asia. In that sense the age of Mackinder offers a cautionary tale for today. China is presumably cast in the role of Russia when you transpose the Heartland thesis to Southeast Asia. Beijing certainly places enormous value on its “indisputable” claims to regional islands and waters. But there’s no Germany nearby to act as a counterweight to an aspiring hegemon. Nor does a faraway great power—a Great Britain—occupy an India, adjacent to the Heartland, from which it can contend for mastery of the geographic pivot. The United States’ strategic position in Southeast Asia cannot begin to approximate that held by British India a century ago.

A parting note on the Heartsea thesis. The South China Sea is not the first expanse for which pundits have advanced extravagant claims. Maritime enthusiasts on the subcontinent are fond of quoting an apocryphal passage from Mahan, to the effect that whoever commands the Indian Ocean will rule the world in the 21st century. If not just India but all powers with interests in South Asia embraced that logic, the region could become a crucible for conflict—whether the logic is sound or not. Policymakers, strategists, and ordinary citizens must think carefully before accepting the seductive theories put forward by a Mackinder or Mahan. Caveat emptor.