- After the sinking of the RMS Lusitania in 1915, the U.S. initially adopted a policy of neutrality.
- However, the resumption of unrestricted submarine warfare by Germany and the Zimmerman Telegram, which revealed Germany's intention to ally with Mexico against the U.S., led to growing public support for intervention.
- On April 6, 1917, the United States declared war on Germany, entering World War I on the side of the Allied Powers.
Mobilization of Troops and Resources:
- The U.S. military faced the challenge of mobilizing and training a large army quickly.
- Through conscription, known as the Selective Service Act of 1917, over 4 million American men were drafted into military service.
- The U.S. also mobilized its industrial capacity, expanding production of war materiel, such as weapons, ammunition, and supplies.
American Expeditionary Force (AEF):
- General John J. Pershing led the American Expeditionary Force (AEF), which operated independently from the British and French armies.
- The AEF engaged in major battles, including the Second Battle of the Marne and the Meuse-Argonne Offensive, contributing significantly to the Allied victory in 1918.
Cultural and Economic Impact:
- World War I had profound cultural and economic effects on the United States.
- It marked the beginning of the U.S. rise as a global power and led to the expansion of the American economy, particularly in the manufacturing sector.
- Socially, the war brought increased opportunities for women in the workforce and spurred the development of new technologies and medical advances.
Isolationism and the League of Nations:
- After the war, there was a strong public sentiment in the U.S. for isolationism and a desire to avoid future foreign conflicts.
- The U.S. rejected the Treaty of Versailles and declined to join the League of Nations, an international organization formed to promote peace and prevent future wars.
In summary, the U.S. response to World War I included declaring war on Germany in 1917, mobilizing troops and resources, forming the AEF, and contributing to the Allied victory. However, the war also led to a prevailing isolationist sentiment, which shaped American foreign policy for several years to come.