World War I (1914–18) CausesCauses of U.S. EntryMilitary and Diplomatic CourseDomestic CoursePostwar ImpactChanging Interpretations
World War I (1914–18): Causes Although the United States did not enter World War I until 1917, the outbreak of that war in 1914, and its underlying causes and consequences, deeply and immediately affected America's position both at home and abroad.