Every one-hundred years, since the Colonial era, America has changed its foreign policy. There is reason to suspect that these transformations represent not only changes in external ideas, or in intellectual fashion, but also changes in the interior condition of the American soul. From the “Spirit of ’76” and the Monroe Doctrine, to the nineteenth-century’s forays into nascent imperialism, to twentieth-century Wilsonian idealism, America’s presence on the world stage has been progressively bolder and increasingly untethered to any fixed conception of America’s character and interests. . . .