For some reason American militarists think its important for the U.S. to control the land mass on the opposite side of the world, which just happens to encompass both Russia and China. From Tom Luongo at tomluongo.me:
All of us so-called geopolitical analysts owe a debt to Halford John Mackinder. His 1904 paper, “The Geographical Pivot of History” is the basis for nearly all strategic thinking in today’s policy rooms, think tanks, and military academies of the West.
We’ve all heard the first three rules of Mackinder:
Who rules Eastern Europe commands the Heartland
Who rules the Heartland commands the World Island
Who rules the World Island commands the world
Because of the dominance of Mackinder’s ideas and the policies erected to support it, the world has been subjected to endless conflict over his conception of the “World Island,” which is basically Eurasia.
And that’s why there can be no losing for the West in Ukraine. To the Mackinderists at the top of the power structures in London, Washington D.C. and Brussels, losing Ukraine means losing the entire world, because they have this very-outdated view of world geography.
Mackinder-ism in today’s world is a tautology, reducing to: We have to control the Heartland because we can’t lose the Heartland.