Between 1929 and 1941, America suffered the deepest and longest economic slump of the twentieth century. By 1932, industrial output had dropped to the same level as twenty years earlier. Unemployment reached 25 percent. There was widespread homelessness, migration, and even starvation. The causes of the Depression included overproduction, too much private debt, and speculative investments. The glamorous decade of the Roaring Twenties had led to inequalities of many kinds.

Through the need for increased federal aid, the Depression triggered a radical change in the relationship between Americans and their government. After a decade of conservative, isolationist politics, President Franklin D. Roosevelt (1882–1945) introduced New Deal legislation to help get people back to work. It funded building projects, regulated wages, and encouraged cultural programs of a distinctly American flavor. The Depression ended with America's entry into World War II (1939–45). The country rallied to support its troops and soon regained a vigorous...