What overt actions cause various nations to make a commitment to the war?

World War I (1914-1918) Causes Causes of U. S. Entry Military and Diplomatic Course Domestic Course Postwar Impact Changing 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.