10.2 American Expeditionary Forces and Military Contribution

The American Expeditionary Forces (AEF) marked the U.S.'s decisive entry into World War I. Under General Pershing's leadership, the AEF grew from 14,000 to 2 million troops, maintaining independence from Allied forces and overcoming logistical challenges to deploy in Europe.

The AEF's arrival in 1917-1918 boosted Allied morale and tipped the balance against exhausted Central Powers. American forces played crucial roles in key battles like Belleau Wood and the Meuse-Argonne Offensive, demonstrating their combat effectiveness and contributing to Germany's eventual defeat.

Formation of the AEF

Establishment and Leadership

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• American Expeditionary Forces (AEF) established in 1917 after United States entered World War I
• General John J. Pershing appointed commander-in-chief by President Woodrow Wilson
• Pershing maintained AEF as independent fighting force resisted pressure to integrate into British and French units
• AEF expanded rapidly from 14,000 men in June 1917 to over 2 million troops by November 1918
• Organizational structure modeled after European armies adapted to American military traditions
  • Larger divisions compared to European counterparts (approximately 28,000 men each)

Composition and Recruitment

• AEF primarily composed of conscripted and volunteer soldiers from diverse backgrounds
  • Included recent immigrants reflected demographic makeup of early 20th century America (Irish, Italian, Eastern European)
• Implemented Selective Service Act of 1917 required all men aged 21-30 to register for potential military service
• Recruitment efforts utilized patriotic propaganda posters (Uncle Sam "I Want You")
• African American soldiers served in segregated units faced discrimination despite their contributions

Logistical Challenges

• Overcame significant hurdles in transporting and supplying large force across Atlantic Ocean
• Implemented convoy system protected troop and supply ships from German U-boat attacks
• Constructed new port facilities in France improved efficiency of troop and supply movement
  • Expanded existing ports (Brest, Saint-Nazaire)
• Faced equipment shortages often relied on Allied-supplied weapons and equipment
  • Particularly in areas of artillery and aircraft (French 75mm field guns, British Sopwith Camel fighters)
• Established Services of Supply (SOS) managed logistics for AEF operations in Europe
  • Built extensive network of supply depots, repair facilities, and transportation infrastructure

AEF Contributions on the Western Front

Strategic Impact

• Provided fresh manpower and resources to Allied cause tipped balance against exhausted Central Powers
• Forced Germany to attempt decisive victory before full U.S. deployment led to overextension and collapse of German military capabilities
• Allowed Allies to maintain pressure on German forces during Spring Offensive of 1918
• Contributed to failure of Germany's final push ultimately led to armistice of November 11, 1918

Tactical Innovations

• Emphasized open warfare and maneuver contrasted with dominant trench warfare tactics
• Influenced Allied operational planning in 1918 shifted focus towards more mobile operations
• Integrated new technologies into operations advanced Allied combined arms tactics
  • Incorporated tank warfare (used French Renault FT tanks)
  • Utilized air support for reconnaissance and ground attack missions (employed Spad XIII fighters)
• AEF's emphasis on rifle marksmanship and individual initiative improved small-unit tactics
  • Particularly effective in wooded and urban combat scenarios (Belleau Wood, Meuse-Argonne)

Logistical Contributions

• Developed extensive Services of Supply system supported large-scale operations far from home soil
• Established model for future American expeditionary warfare influenced military logistics in World War II
• Constructed and operated port facilities, railways, and supply depots in France
  • Built 82 new ship berths, nearly 1,000 miles of standard-gauge railway track
• Implemented motorized transport system improved efficiency of supply distribution to front lines
  • Utilized over 50,000 trucks by war's end

Key Battles of the AEF

Battle of Belleau Wood

• Fought June 1-26, 1918 in Belleau Wood, northwest of Paris
• Defining engagement for U.S. Marine Corps demonstrated American resolve and combat effectiveness
• Marines earned nickname "Devil Dogs" (Teufelshunde) from German opponents
• Resulted in 9,777 American casualties including 1,811 killed
• Tactical significance cleared German forces from strategically important woodland area
• Halted German advance towards Paris during Spring Offensive

Meuse-Argonne Offensive

• Largest and costliest operation in U.S. military history to that point (September 26 - November 11, 1918)
• Involved 1.2 million American soldiers part of final Allied offensive of World War I
• Broke through Hindenburg Line forced German high command to seek armistice
• Resulted in over 350,000 American casualties including 26,277 killed
• Demonstrated AEF's ability to conduct large-scale, sustained offensive operations
• Captured strategic railway hub at Sedan cut off German supply lines

Battle of Saint-Mihiel

• First independent American operation of the war (September 12-16, 1918)
• Reduced Saint-Mihiel salient bulge in German lines that had existed since 1914
• Showcased AEF's ability to plan and execute large-scale offensives
• Involved over 500,000 American troops supported by French colonial forces
• Utilized combined arms approach incorporated tanks, aircraft, and artillery
• Resulted in capture of 16,000 German prisoners and 450 artillery pieces

American Intervention in WWI

Morale and Psychological Impact

• Arrival of American forces in 1917-1918 provided crucial morale boost to Allies
• Countered war-weariness and mutinies among French and British troops
• American enthusiasm and fresh resources reinvigorated Allied war effort
• Presence of U.S. troops demoralized German forces facing seemingly endless stream of reinforcements

Economic and Industrial Support

• American industrial output overwhelmed Germany's ability to continue the war
• Provided massive amounts of war materiel to Allies (ammunition, vehicles, food supplies)
• Implemented Liberty Loan program raised over $17 billion for war effort
• Mobilized American industry for wartime production (Ford Motor Company produced military vehicles)

Geopolitical Consequences

• AEF's combat performance demonstrated America's emergence as major military power
• Shifted global geopolitical dynamics elevated United States to world power status
• Contributed to President Woodrow Wilson's influential role in peace negotiations
  • Proposed Fourteen Points as basis for post-war settlement
• American military success strengthened U.S. position in negotiating Treaty of Versailles
• Experience gained by AEF influenced U.S. military doctrine and preparedness in interwar period
  • Shaped America's approach to World War II (emphasis on combined arms, large-scale operations)