USII.6a  Causes and Events that Led to American Involvement in WWII

The student will demonstrate knowledge of the major causes and effects of American involvement in World War II by
a) identifying the causes and events that led to American involvement in the war, including the attack on Pearl Harbor.

How did post-World War I Europe set the stage for World War II?

How did the rise of fascism affect world events following World War I?

Political and economic conditions in Europe following World War I led to the rise of fascism and to World War II

Benito Mussolini and Adolf Hitler  

The rise of fascism threatened peace in Europe and Asia.

Causes of World War II
Political instability and economic devastation in Europe resulting from World War I
Worldwide depression
High war debt owed by Germany
High inflation
Massive unemployment
Rise of Fascism
Fascism is a political philosophy in which total power is given to a dictator and individual freedoms are denied.
Fascist dictators included Adolf Hitler (Germany), Benito Mussolini (Italy), and Hideki Tojo (Japan).
  These dictators led the countries that became known as the Axis Powers.

How did American policy toward events in Europe and Asia change over time?

As conflict grew in Europe and Asia, American foreign policy evolved from neutrality to direct involvement.

The Allies
Democratic nations (the United States, Great Britain, Canada) were known as the Allies. The Soviet Union joined the Allies after being invaded by Germany.

Allied leaders included Franklin D. Roosevelt and later Harry S. Truman (United States), Winston Churchill (Great Britain), Joseph Stalin (Soviet Union)

Gradual change in American policy from neutrality to involvement

Isolationism (Great Depression, legacy of World War I)

Economic aid to Allies

Direct involvement in the war


The Big Three - The Allied Leaders at the Yalta Conference

War in the Pacific

Rising tension developed between the United States and Japan because of Japanese aggression in East Asia.

On December 7, 1941, Japan attacked the United States at Pearl Harbor without warning.

The United States declared war on Japan.

Germany declared war on the United States.


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  Pearl Harbor -
USS Arizona burned for two days after being hit by a Japanese shell. Parts of the ship were salvaged, but the wreck remains at Pearl Harbor to this day.