Gage identifies Hoover as a central figure within the “American Century.” The term itself was coined in 1941 by Henry Luce, the publisher of Time and Life magazines, in an editorial where he called for the United States to end its neutrality in the Second World War and embrace its mission to spread freedom throughout the globe. Afterward, the term retroactively referred to the emergence of the United States as a major world power over the course of the 20th century. Since the term denotes a new era in American history, it tends to exaggerate the differences with what came before. World War II–era champions of intervention called for an end to American “isolationism,” but the United States had never been removed from world affairs. As early as 1823, President James Monroe declared the entire Western Hemisphere to be under US protection against further European colonization. The expansion across the western frontier entailed the virtual annihilation of Indigenous peoples, recognized by the US government as sovereign nations, along with the periodic risk of war with European powers still claiming territory in the Americas.

But by comparison with what it would become, the United States at the time of Hoover’s birth in 1895 was a regional rather than world power, with a small military and mostly commercial interests in Europe and Asia.