Contextualizing Period 7, 1890-1945

By the end of this lesson, students will be able to:

• Explain why Period 7 is conventionally bounded by 1890 (the census-declared closing of the western frontier) and 1945 (the end of the Second World War).
• Identify the three braided developments that organize Unit 7: economic and demographic transformation, the long argument over reform, and the U.S. shift from continental power to global hegemon.
• Describe how the closing frontier, industrialization, and overseas ambition reshaped American debate about the country's proper role in the world.
• Use Skill 4 (Contextualization) to situate at least one Period 7 development inside its broader national and global setting.
• Account for the continuities that connect Gilded Age America to the postwar superpower of 1945, and the shifts that distinguish Period 7 from Period 8 (the Cold War era).

Period 7 is the half century in which the United States grew from a continental republic with a thin overseas reach into the most powerful country on earth. In 1890, three out of every five Americans still lived on a farm or in a town of fewer than twenty-five hundred people, the West was an open object of imperial fantasy, and the nation's overseas presence amounted to a few coaling stations. By 1945, more than half the population lived in cities, the country had fought two world wars, the federal government had built a permanent regulatory and welfare apparatus during the New Deal, and the United States was the only nation on earth with a functioning industrial economy and an atomic arsenal. Three braided developments produced that transformation: an economic and demographic remaking of the country (KC-7.1, KC-7.2), a sustained political argument over reform that ran from the Progressive Era through the New Deal (KC-7.1.II, KC-7.1.III), and a steady move from continental to global power (KC-7.3).

The economic and demographic transformation began with the closing frontier. The 1890 Census reported that population had spread so thinly across the West that the line between settled and unsettled territory was no longer meaningful, and three years later the historian Frederick Jackson Turner argued before the American Historical Association that the frontier had been the engine of American democracy itself and that its closing demanded a new outlet for the national impulse. Whatever historians have since done with Turner's thesis, contemporaries seized on it as warrant for empire. At the same time, the Second Industrial Revolution remade daily life: assembly-line factories, steel mills, electric grids, and the automobile produced higher standards of living, longer commutes, and a consumer economy organized around mass-market goods (KC-7.1.I.A). The country urbanized so quickly that the 1920 Census recorded for the first time that more than half the population lived in cities (KC-7.1.I.B). Two great migrations supplied the labor: more than fifteen million southern and eastern Europeans entered through Ellis Island between 1890 and 1924 (KC-7.2.II.A), and beginning during the First World War some six million African Americans left the rural South for the industrial cities of the North in the Great Migration (KC-7.2.II.C). Both flows reshaped the country's demographic geography and produced the nativist backlash, restrictive 1924 immigration law, and Harlem Renaissance that Topic 7.8 will examine in detail.

Out of that transformation came a half century of argument about reform. The first wave was Progressivism, a loose coalition of muckraking journalists, middle-class women's clubs, settlement-house workers, and university-trained policy professionals who pressed for federal regulation of corporate power, the abolition of child labor, banking reform, food and drug inspection, and women's suffrage (KC-7.1.II.A, KC-7.1.II.B). Progressives were never a single party; they backed Theodore Roosevelt in 1912, Woodrow Wilson in 1916, and several rejected the label entirely (KC-7.1.II.C). The second wave came after the 1929 stock-market crash and the bank panics of 1932 toppled the Republican order Progressives had partly built. Franklin Roosevelt's New Deal, beginning in 1933, used federal power on a scale no peacetime American government had attempted: relief programs for the unemployed, recovery measures for industry and agriculture, and structural reforms such as Social Security, the Wagner Act, and the Securities and Exchange Commission (KC-7.1.III.A). Radicals, populist demagogues such as Huey Long, and the labor movement pushed Roosevelt leftward; the conservative wing of the Supreme Court and southern Democrats in Congress pushed back (KC-7.1.III.B). The New Deal did not end the Depression on its own, but it left a regulatory architecture and a long-running political coalition of urban ethnics, African Americans, organized labor, and the white South that would define national politics into the 1960s (KC-7.1.III.C; Theme PCE).

The third development was the rise of the United States as a world power. The 1898 Spanish-American War ran for ten weeks and ended with American forces in possession of Puerto Rico, Guam, the Philippines, and a protectorate over Cuba (KC-7.3.I.C). Imperialists led by Theodore Roosevelt, Henry Cabot Lodge, and the naval theorist Alfred Thayer Mahan pointed to overseas markets, naval strategy, and racial theories of Anglo-Saxon destiny in arguing that empire was the country's natural next step (KC-7.3.I.A). Anti-imperialists led by William Jennings Bryan, Mark Twain, and Andrew Carnegie countered with appeals to the country's republican tradition of self-government and, in some cases, with their own racial theories arguing against absorbing non-white populations into the body politic (KC-7.3.I.B). The United States then stayed officially neutral when the European powers went to war in 1914, entered the conflict in April 1917 under Wilson's promise of a war for democracy and freedom of the seas (KC-7.3.II.A), helped tip the balance toward the Allies (KC-7.3.II.B), and watched its own Senate refuse to ratify Wilson's Treaty of Versailles or to join the League of Nations he had built into it (KC-7.3.II.C). The interwar years produced a paradoxical foreign policy of unilateral economic and diplomatic engagement combined with formal disengagement from collective security (KC-7.3.II.D), a pattern broken only when Japan attacked Pearl Harbor on December 7, 1941, and the United States entered a second global war (Theme WOR).

The Second World War transformed the country a final time. Mass mobilization for the war effort ended the Great Depression where the New Deal had not, putting sixteen million Americans into uniform and millions more into shipyards, aircraft plants, and tank factories (KC-7.3.III.B). The home front raised difficult questions about American values: the federal government interned roughly 120,000 people of Japanese ancestry, two-thirds of them U.S. citizens, in remote camps; African American soldiers fought a segregated war while civil-rights organizations launched the Double V campaign for victory abroad and at home; and physicists at Los Alamos built the atomic weapons that ended the war over Hiroshima and Nagasaki and that opened the moral debate that has continued ever since (KC-7.3.III.C, KC-7.3.III.D). Allied victory was won through cooperation among the United States, the Soviet Union, and Britain, technological and scientific advances, the contributions of servicemen and women, the island-hopping campaign in the Pacific, and the D-Day invasion of Normandy in June 1944 (KC-7.3.III.D). When the fighting ended in August 1945, Asia and Europe lay in ruins, and the United States, almost alone among the major belligerents, came out of the war richer than it had entered. Out of that asymmetry came the postwar order: the United Nations, the Bretton Woods financial system, occupation governments in Germany and Japan, and a few short years later the Cold War contest with the Soviet Union that defines Period 8 (KC-7.3.III.E).

Six themes will recur across the next fourteen lessons. The WOR theme follows imperialism, the world wars, interwar foreign policy, and postwar diplomacy. The PCE theme tracks the Progressive and New Deal reform arcs and the conservative reactions that limited each. The MIG theme covers the new immigration, immigration restriction, and the Great Migration. The ARC theme handles the cultural conflicts of the 1920s, including Prohibition, the Scopes trial, the Klan revival, and the Harlem Renaissance. The WXT theme traces consumer capitalism, the 1929 crash, and the New Deal's regulatory response. The SOC theme frames wartime mobilization. Topics 7.1 and 7.15 are unit-synthesis lessons rather than thematic lessons; the CED page assigns them no single Thematic Focus, and the canonical map preserves that distinction. Topics 7.4 and 7.8 carry two thematic focuses each, a feature of Period 7 that no other unit in the course displays.

A contextualizing lesson works best when it samples sources that span the period. The four excerpts below mark the political, the demographic, and the rhetorical bookends of Period 7.

1. (Continuity and Change) Compare the United States in 1890 with the United States in 1945. Identify two continuities and two significant shifts. Which set is more historically consequential, and on what grounds?
2. (Causation) Trace the causal chain from the closing of the western frontier to the acquisition of an overseas empire in 1898. At which step in the chain do you think a different decision could have produced a different outcome, and why?
3. (Comparison) Compare the Progressive Era reform agenda with the New Deal reform agenda. What does the comparison reveal about the changing relationship between the federal government and the American economy?
4. (Continuity and Change) The 1920 Census recorded an urban-majority America. Identify one cultural conflict of the 1920s in which the urban-rural divide is visible, and explain how that divide reshaped national politics.
5. (Causation) Account for the global setting that shaped American entry into the Second World War. How did developments in Europe, Asia, and the Pacific between 1931 and 1941 narrow the country's range of foreign-policy choices?

Draft alignment — pending educator review. AP USH codes correspond to the official College Board Course and Exam Description (Effective Fall 2023, Version 1). Statements below are paraphrased in the CountryReports voice; refer to the College Board's published CED for verbatim wording.