1. Section 1 America Enters World War I
World War I and the 1920s ( )
Section 1 America Enters World War I

2. Lesson 1 America Enters World War I
World War I and the 1920s ( )
Lesson 1 America Enters World War I
Learning Objectives
Identify the causes of World War I.
Analyze the impact of technological innovations in weaponry that resulted in stalemate on the Western Front.
Analyze reasons behind isolationism and neutrality in the United States before 1917.
Explain why the United States entered the conflict on the side of the Allies.
Key Terms
Alsace-Lorraine
militarism
Francis Ferdinand
William II
Western Front
Casualties
contraband
U-boats
Lusitania
Zimmermann note

3. The Causes of World War I
M.A.I.N
Historians have traditionally cited four long-term causes of the First World War
MILITARISM – The growth of nationalism and imperialism led to increased military spending
ALLIANCE SYSTEM – By 1907 Europe was divided into two armed camps (allies and central powers)
IMPERIALISM – Economic and political control over weaker nations
NATIONALISM – a devotion to the interests and culture of one’s nation

4. Causes of World War I: Militarism: Alliance System: Imperialism:
European nations built large armies (especially Germany) – prepare for war
Other nations tried to keep up (naval power)
New Weapons
Machine Guns, artillery, tanks, submarines, airplanes
Alliance System:
Allies, consisted of France, Britain, and Russia (US would join later)
Triple Alliance / Central Powers, consisted of Germany, Austria-Hungary, and Italy
Imperialism:
Nations around the world were overtaking weaker ones
Provided the resources to build a larger empire
Nationalism
National pride led to rivalries and conflicts between nations
Leads to industrial output, trade and completion for foreign land

5. The Causes of World War I
Analyze Maps Based on the map, what can you predict about where the major battles of World War I would be fought?

6. 1. The Alliance System
Triple Entente:
Triple Alliance:

7. Two Armed Camps!
Allied Powers:
Central Powers:

9. The Causes of World War I
Analyze Charts Which nation had the largest navy at the beginning of World War I? Which had the most troops?

10. Assassination of Archduke Franz Ferdinand Video
“THE SPARK”
The Great War Begins
Assassination of Archduke Franz Ferdinand Video
Gavrilo Princip
Archduke Ferdinand

11. The Great War Begins
Austria-Hungry demands that Serbia help in the investigation
Serbia refuses
Austria-Hungry Declares war on Serbia (July 28th 1914)
Alliance System
Russia pledged to protect Serbia
Russia declares war on Austria… Germany declares war on Russia…France declares war on Germany…Great Britain declares war on Germany…

12. “I’ll be home by Christmas”
THE FIGHTING BEGINS
Alliance system pulled one nation after another into the conflict – The Great War had begun
On August 3, 1914, Germany invaded Belgium, following a strategy known as the Schliefflen Plan
This plan called for a quick strike through Belgium to Paris, France
Great Britain declared war on Germany
Next, Germany would attack Russia
The plan was designed to prevent a two-front war for Germany
Many countries believed that a strong military force would prevent war. 30 Countries fought in the “Great War”
“I’ll be home by Christmas”
The Schliefflen Plan

13. The Great War Begins
Analyze Maps What challenge did Germany’s location present to its pursuit of victory in the war?

14. The War Becomes A Stalemate:
Battle of the Marne
Germany invades France
British and French counter
Both allies and central powers forces dug in for a long fight
Trench warfare – hand dug channels that were created all across Europe
There were 3 types of trenches:
front line
Support
reserve
Between enemy trenches was “no man’s land” – an area pockmarked with shell craters and filled with barbed wire
Movie: War Horse
Trench warfare

15. Should America Join the Fight?
In 1914, most Americans saw no reason to join a struggle 3,000 miles away – they wanted neutrality
European conflict
Many Americans felt close to the British because of a shared ancestry and language
France aid during the Rev. War.
Many immigrants saw their countries being ripped apart.
Immigrants felt an allegiance to their home country

16. The United States Remains Neutral
Views on WWI
Isolationists – not America’s business
Interventionists – protect American interests in Europe (Allies)
Internationalists – should be active in world affairs… not enter the war
Analyze Political Cartoons Based on the cartoon, what can you infer about President Wilson’s attitude toward the war?

17. Reasons for U.S. Entry into the War
President Wilson – vowed to remain neutral
Blockades – preventing another nation from transporting goods
Britain blocked German boats
Germany used U-Boats
During the first two years of the war, America was selling the allied forces war materials and weapons
They used the sea to transport the goods
Germany warned that any ship found in the waters around Britain would be sunk

18. Reasons for U.S. Entry into the War
German U-boats destroyed more than 11 million tons of Allied shipping and killed nearly 14,000 people.Analyze Maps Why were U-boat attacks clustered in particular areas?

19. The Lusitania Disaster:
The Lusitania was a British passenger liner
A German U-boat sank the Lusitania, killing all aboard (1200 people) including 128 American tourists
The Germans claimed the ship was carrying Allied ammunition
Germans promise to not to sink any more ships
Violated promise
USS Sussex – Germany sinks another passenger ship
Sussex Pledge
Americans were outraged and public opinion turned against Germany and the Central Powers

20. Preparations for War Wilson prepares for War Neutral No Longer
“preparedness”
National Defense Act – expanded size of army
Naval Construction Act – built more warships
Neutral No Longer
Zimmerman note
German foreign minister Arthur Zimmerman
Telegram to Mexico
Alliance with Mexico
Help Mexico regain territory lost in the Mexican American War
(Texas, new Mexico, Arizona)
Telegram intercepted by British
America Enters WWI
April 2, 1917
“Make the world safe for democracy”