AP World History: Modern — World War I and the Interwar Order (Unit 7.1–7.4)

Shifting power after 1900

The process by which industrial capacity, imperial rivalries, nationalism, and new military technology changed which states had leverage and made regional crises more likely to escalate into global war.

Great Powers

Europe’s major states (especially Britain, France, Germany, Austria-Hungary, Russia, and increasingly Italy) whose competition and diplomacy shaped international security before WWI.

Industrialization and military capacity

The link between industrial output and the ability to produce weapons, railroads, and mobilize mass armies; Germany’s rapid growth after 1871 forced rivals to rethink strategy.

Imperial competition

Rivalry among empires for prestige and strategic advantage (bases, chokepoints, raw materials), which increased distrust and tension among European powers.

Nationalism

Loyalty to a shared identity (language, culture, history) that could unify states (Germany, Italy) but also destabilize multiethnic empires (Austria-Hungary, Ottoman Empire), especially in the Balkans.

Militarism

The belief that military strength is essential to national power and that war is an acceptable tool of policy, encouraging heavy investment in armaments and war planning.

Security dilemma

A cycle where one state’s defensive military buildup is perceived as threatening by rivals, prompting them to arm as well—making everyone less secure.

Triple Alliance

Pre-WWI alliance system linking Germany, Austria-Hungary, and Italy.

Triple Entente

Pre-WWI alignment connecting France, Russia, and Britain.

Entangling commitments

Alliance obligations that can pull additional states into a conflict when one member is threatened, spreading a crisis and raising the stakes.

Balkans as a pressure point

A volatile region where declining imperial control, rising nationalism (including Pan-Slavism), and Great Power rivalry combined to make conflicts more explosive.

Assassination of Archduke Franz Ferdinand

The June 28, 1914 killing of Austria-Hungary’s heir in Sarajevo; it served as the immediate trigger that set off escalation in an already tense system.

July Crisis

The rapid chain reaction of decisions in summer 1914 (ultimatums, declarations of war, mobilizations, invasion of Belgium) that narrowed options for peace and expanded conflict.

Trench warfare

A defensive, fortified style of fighting—especially on the Western Front—produced by machine guns, artillery, barbed wire, and failed breakthroughs, leading to stalemate and heavy casualties.

Total war

Warfare requiring full mobilization of society: governments direct production, ration resources, use censorship/propaganda, and expand conscription and labor organization, blurring home front and battlefield.

Treaty of Versailles (1919)

The major post-WWI settlement with Germany that imposed penalties (including reparations), redrew borders, created mandates, and contributed to interwar instability; it also helped establish the League of Nations (which the U.S. did not join).

War debts

Money governments borrowed during WWI to finance total war, leaving many states with heavy postwar financial burdens.

Reparations

Payments demanded from Germany after WWI (especially under Versailles), contributing to a tense international financial chain and economic instability.

Reconstruction costs

The expense of rebuilding damaged regions and restarting production after WWI, adding to economic strain in Europe.

Hyperinflation

Extremely rapid inflation (notably in Germany in the early 1920s) that destroyed savings, destabilized wages, and undermined confidence in governments.

Great Depression

A global economic crisis beginning after the 1929 U.S. stock market crash that spread through interconnected trade and finance, causing bank failures, collapsing demand, mass unemployment, and declining world trade.

Keynesian economics

The idea that during downturns the government can stimulate demand through increased spending and intervention to stabilize the economy.

New Deal

U.S. interwar program that expanded federal intervention through relief measures and public works, reflecting Keynesian-style responses to the Great Depression.

Protectionism

Economic policy of raising tariffs and restricting imports to protect domestic jobs and industry; often provoked retaliation and reduced global trade.

Smoot-Hawley Tariff (1930)

A major U.S. tariff that exemplified interwar protectionism and helped worsen the contraction of international trade through retaliatory measures.