APUSH Unit 7 Notes: The Great War’s Aftermath and the Transforming 1920s

Neutrality (WWI)

The U.S. policy at the start of World War I of not formally taking sides militarily in the European conflict, though economic ties and events made neutrality difficult to sustain.

Unrestricted submarine warfare

Germany’s strategy of using U-boats to sink ships headed to Allied ports without warning, including neutral vessels, which helped push the U.S. toward war in 1917.

Zimmermann Telegram (1917)

A secret German message proposing an alliance with Mexico if the U.S. entered WWI, suggesting Mexico might regain lost territory; it inflamed U.S. public opinion against Germany.

Lusitania (1915)

A British passenger liner sunk by a German submarine; the deaths of over 100 Americans shifted U.S. opinion and increased pressure on President Wilson, though it did not immediately bring U.S. entry into WWI.

Sussex Pledge (1916)

Germany’s temporary promise to limit submarine attacks on passenger ships after a submarine incident, reflecting concern about provoking U.S. entry into WWI.

Selective Service Act (1917)

Law that created a draft (conscription) to build a large U.S. army for World War I rather than relying only on volunteers.

Armistice (November 11, 1918)

The agreement that ended the fighting in World War I, accepted by Germany amid military exhaustion and domestic unrest.

Committee on Public Information (CPI)

A U.S. government propaganda agency led by George Creel that promoted support for World War I through posters, films, speeches, and “Four Minute Men.”

Espionage Act (1917)

Wartime law targeting interference with the war effort and the draft; used to prosecute antiwar activities and limit dissent.

Sedition Act (1918)

Law that expanded wartime restrictions by penalizing “disloyal” or critical speech about the U.S. government and the war effort.

Schenck v. United States (1919)

Supreme Court case upholding restrictions on anti-draft speech; introduced the idea that speech creating a “clear and present danger” could be limited in wartime.

Great Migration

The movement of many African Americans from the rural South to northern cities during and after WWI for industrial jobs and to escape Jim Crow violence, reshaping urban culture and politics while intensifying racial tensions.

Nineteenth Amendment (1920)

Constitutional amendment granting women the right to vote; momentum was strengthened by women’s expanded wartime roles and arguments about citizenship.

Fourteen Points

Woodrow Wilson’s post–World War I goals for peace, promoting ideas such as open diplomacy, freer trade, and national self-determination (though difficult to apply consistently).

Treaty of Versailles (1919)

The main peace treaty ending WWI; it included territorial changes and imposed blame and heavy burdens on Germany, falling short of Wilson’s idealistic vision.

League of Nations

International organization proposed after WWI to deter aggression through collective security; central to Wilson’s peace plan but never joined by the United States.

Article X (League Covenant)

A League of Nations provision associated with collective security obligations; critics feared it could commit the U.S. to future wars without a congressional declaration of war.

Irreconcilables

Senators who opposed the Treaty of Versailles and U.S. membership in the League of Nations under any circumstances.

Reservationists

Senators (including Henry Cabot Lodge) willing to approve the Treaty of Versailles only with amendments/reservations limiting U.S. obligations, especially regarding the League.

Mass production

The large-scale manufacturing of standardized goods (notably automobiles and appliances) that expanded in the 1920s, reshaping labor, business organization, and consumer expectations.

Prohibition

The national ban on the manufacture, sale, and transport of alcohol established by the Eighteenth Amendment (1919) and enforced by the Volstead Act; led to uneven enforcement, bootlegging, speakeasies, and organized crime.

Scopes Trial (1925)

A highly publicized Tennessee case over teaching evolution; it symbolized the broader 1920s conflict between modern scientific ideas and religious fundamentalism.

First Red Scare (1919–1920)

A period of fear of communism and anarchism after WWI and the Russian Revolution, intensified by strikes and prompting government actions that often violated civil liberties.

Nativism

The belief that native-born Americans deserve priority and that immigrants are threatening; in the post-WWI era it was fueled by national security fears, economic anxiety, Red Scare ideology, and racial/religious prejudice.

Immigration Act of 1924 (Johnson-Reed Act)

Law that tightened national-origins quotas to favor northern and western Europe, sharply limited southern and eastern Europe, and effectively barred immigration from Asia—aiming to shape America’s future ethnic composition.