When the United States entered World War I, the nation abandoned its historic aloofness from European affairs and plunged into the unfamiliar morass of global power politics. On the home front, economic mobilization for World War I rapidly accelerated the prewar progressive trend toward more government control over the economy. Both of these changes were wrenching transformations for Americans because they seemed to contradict the nation’s cherished traditions of diplomatic isolation and unregulated markets. And yet, both tossed-off traditions came back with a vengeance in the postwar years as the nation returned to isolation abroad and minimal government at home.

Americans in the 1914-1929 period oscillated back and forth between opposite poles of foreign and domestic policy, seemingly unable to agree on what should be the nation’s role in the world or the government’s role in the economy. These were years when the United States accepted, but then rejected the mantle of world leadership. Similarly, government regulation of business was drastically increased, but then almost completely abandoned. The failure of Americans to solve key problems of security and governance in World War I and the 1920s would lead directly to a major depression in the 1930s and another world war in the 1940s. Hence for Americans these years tell a cautionary tale about the consequences of too little government at home and too much isolation abroad.