Introduction: Why World Wars Matter in APUSH
Two of the most heavily tested topics in AP U.S. History are World War I and World War II. These conflicts reshaped America’s role in global affairs, shifted domestic policies, and redefined U.S. identity on the world stage.
On the APUSH exam, expect questions on:
- The causes of U.S. involvement
- Major events during the wars
- The effects on society, politics, and economy
- The global legacy of U.S. actions
This guide gives you a clear, exam-focused overview — with help from RevisionDojo, where you’ll find detailed timelines, practice DBQs, and multiple-choice drills.
World War I (1914–1918)
Causes of U.S. Entry
- Unrestricted Submarine Warfare: German U-boats sank ships like the Lusitania (1915).
- Zimmermann Telegram (1917): Germany encouraged Mexico to attack the U.S. if America joined the war.
- Economic Ties: Strong trade with Britain and France.
- “Make the World Safe for Democracy”: Wilson’s idealistic justification.
Major Events
- U.S. Declares War (1917): After years of neutrality.
- Selective Service Act: Draft to build an army quickly.
- American Expeditionary Force (AEF): Led by General Pershing in Europe.
- Home Front Mobilization: War Industries Board, Committee on Public Information (propaganda), Espionage and Sedition Acts.
