• September 1, 1939 - Germany invades Poland.
• September 27, 1940 - Germany, Japan, and the Soviet
Union sign a pact stating they will not attack each other
and will provide military assistance if attacked by a
nation not already involved in the war.
• December 7, 1941 - Japanese bombers destroy large
portions of the U. S. Navy fleet at Pearl Harbor.
• December 8, 1941 – The United States declares war on
Japan.
• December 11, 1941 - Germany declares war on the
United States.
• December 11, 1941 - The United States declares war
on Germany
Based on the information in the timeline, which causal explanation for U. S.
involvement in World War II is most likely accurate?