THE late Nicholas Spykman, a pioneer in the study of international relations, once said that “he who controls the Rimland controls Eurasia, who controls Eurasia controls the destinies of the world.” This classic statement of geopolitics has guided American foreign policy for more than 60 years. Since June 1940, when the French army collapsed and Hitler seemed poised to dominate Europe, twelve U.S. presidents have followed a grand strategy congruent with the premises and conclusions of Spykman’s dictum.