4.4 The Entry of the United States and the War's Conclusion

The United States' entry into World War I in 1917 marked a turning point. Shifting public opinion, diplomatic tensions, and economic ties to the Allies pushed America to join the fight against Germany and the Central Powers.

American troops and resources provided a crucial boost to the Allied war effort. The influx of fresh soldiers, industrial might, and economic power helped turn the tide, leading to Germany's defeat and the war's conclusion in 1918.

US Entry into World War I

Shifting Public Opinion and Diplomatic Tensions

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• Sinking of the Lusitania in 1915 by German U-boats killed 128 Americans shifted U.S. public opinion against Germany
• Zimmermann Telegram intercepted in 1917 revealed Germany's attempt to ally with Mexico against the United States (further inflamed anti-German sentiment)
• Germany resumed unrestricted submarine warfare in 1917 threatened U.S. commercial interests and freedom of the seas
• Russian Revolution of 1917 and Russia's exit from the war increased pressure on the U.S. to join the Allies (prevent a German victory)

Economic and Ideological Factors

• Economic ties between the United States and Allied powers created vested interest in Allied victory (loans, trade agreements)
• President Woodrow Wilson's ideological shift from neutrality to interventionism influenced by belief in making the world "safe for democracy"
  • Wilson's evolving foreign policy stance
  • Emphasis on moral responsibility in international affairs
• Growing sentiment among American political and business leaders favoring intervention
  • Concerns about post-war economic influence
  • Desire to shape the new world order

American Impact on the War

Military Contributions

• Influx of fresh American troops provided significant numerical advantage to Allied forces on Western Front
  • Over 2 million American soldiers deployed by war's end
  • American Expeditionary Forces maintained operational independence under General John J. Pershing
• Meuse-Argonne Offensive played crucial role in breaking German defenses
  • Largest and bloodiest operation in American military history
  • Involved over 1 million American soldiers
• Implementation of convoy systems by U.S. Navy effectively countered German U-boat threat
  • Secured vital supply lines across the Atlantic
  • Reduced shipping losses by up to 90%

Economic and Morale Boost

• American industrial and economic power enhanced Allies' war effort
  • Supplied crucial resources (steel, oil)
  • Provided weapons and ammunition (rifles, artillery)
  • Offered financial support (war bonds, loans to Allied nations)
• American involvement boosted Allied morale and resolve
  • Psychological impact of fresh troops and resources
  • Demoralized German forces and Central Powers
• President Wilson's Fourteen Points shaped ideological framework for post-war peace negotiations
  • Influenced creation of League of Nations
  • Emphasized principles of self-determination and open diplomacy

Conclusion of World War I

Major Offensives and Battles

• Second Battle of the Marne (July-August 1918) marked last major German offensive and turning point of war
  • Allied forces, including Americans, successfully halted German advance
  • Demonstrated growing strength of Allied coordination
• Hundred Days Offensive (August-November 1918) steadily pushed back German forces
  • Series of Allied attacks along Western Front
  • Led to collapse of Hindenburg Line (Germany's last major defensive position)
• Battle of Amiens (August 1918) demonstrated effectiveness of combined arms warfare
  • Marked beginning of Germany's military decline
  • Utilized tanks, aircraft, and infantry in coordinated assault

Political and Military Collapse of Central Powers

• German Revolution (November 1918) overthrew monarchy
  • Led to internal political instability
  • Further weakened Germany's ability to continue the war
• Signing of separate armistices isolated Germany
  • Bulgaria (September 29, 1918)
  • Ottoman Empire (October 30, 1918)
  • Austria-Hungary (November 3, 1918)
• Battle of Vittorio Veneto (October-November 1918) on Italian Front resulted in complete defeat of Austro-Hungarian forces
  • Led to dissolution of Austro-Hungarian Empire
  • Created power vacuum in Central Europe

Armistice and Treaty of Versailles

Armistice and Immediate Aftermath

• Armistice signed on November 11, 1918 ended hostilities
  • Set stage for peace negotiations
  • Marked pivotal moment in world history
• Ceasefire terms included German withdrawal from occupied territories
  • Evacuation of Rhineland
  • Surrender of naval fleet and submarines

Key Provisions of the Treaty of Versailles

• Treaty signed on June 28, 1919 officially ended state of war between Germany and Allied Powers
• "War Guilt Clause" (Article 231) placed sole responsibility for war on Germany
  • Led to resentment and future political instability in Germany
  • Justified reparations and punitive measures
• Territorial changes mandated by treaty significantly altered European borders
  • Loss of Alsace-Lorraine to France
  • Creation of Polish Corridor
  • Reduction of German colonial possessions
• Severe military restrictions imposed on Germany
  • Limitations on army size (100,000 men)
  • Prohibition of certain weapons (tanks, submarines)
• Establishment of League of Nations represented groundbreaking attempt at international cooperation
  • Aimed to prevent future conflicts through collective security
  • United States ultimately did not join due to domestic political opposition

Long-term Consequences

• Harsh reparations imposed on Germany totaling 132 billion gold marks
  • Crippled German economy
  • Contributed to rise of extremist political movements in interwar period (Nazi Party)
• Redrawing of national boundaries based on principle of self-determination
  • Created new nation-states (Czechoslovakia, Yugoslavia)
  • Led to ethnic tensions and future conflicts
• Treaty's perceived harshness fueled German resentment
  • Provided propaganda material for nationalist movements
  • Undermined stability of Weimar Republic