Although involvement in World War I strengthened the United States economically and diplomatically, it left the nation profoundly unsettled. Racial tensions exploded after the war as African Americans pursued new opportunities and asserted their rights. Meanwhile, labor unrest grew as employers cut wages and sought to break unions. Labor’s power declined sharply in the war’s aftermath, while anxieties over radicalism and immigration prompted a nationwide Red Scare.

The politics of the 1920s brought a backlash against prewar progressivism. The agenda of women reformers met very limited success. Republican administrations pursued probusiness “normalcy” at home and “dollar diplomacy” abroad. Prohibition and the Scopes trial demonstrated the influence religion could exert on public policy, while rising nativism fueled a resurgent Ku Klux Klan and led to sweeping new restrictions on immigration.

Postwar alienation found artistic expression in new forms of modernism, which denounced the dehumanizing effects of war and criticized American materialism and hypocrisy. Spreading throughout the nation from New Orleans, jazz appealed to elite and popular audiences alike. Black artists and intellectuals of the Harlem Renaissance, including many inspired by pan-African ideas, explored the complexities of African American life.

Business thrived and a booming consumer culture, exemplified by the radio, the automobile, and Hollywood films, created new forms of leisure, influencing daily life and challenging older sexual norms. However, the risky speculation and easy credit of the 1920s undermined the foundations of the economy. After the 1929 crash, these factors, along with a range of interconnected global conditions, plunged the United States into the Great Depression.