do you mean what caused us entry into world war one? if so then the sinking of the USS Lusitania by German u-boats was what caused American entry into the war
isolationism
They believed they needed to crush the Allies before American troops arrived.
Japan bombed the US Naval Fleet in Pearl Harbor, Hawaii on December 7th, 1941. This caused the US to declare war on Japan the next day. This officially put the US into World War 2. The day after that, the United States declared war on Germany.
They were confident they could outlast the AlliEd forces
The attack on Pearl Harbor
One of the cause of America entry into World War One was the announcement by Germany that there was unrestricted submarine warfare. The effect of America's entry is that it sped the end of the war.
The Japanese attacked Pearl Harbor December 7, 1941.
the Zimmermann note
Not Sure
Economic gain.
Japanese attack at Pearl Harbour. That's World War 2. The United States entered World War I after the Zimmermann note, which offered German aid for a Mexican invasion of the US, was intercepted, translated and sent to Woodrow Wilson by the British.
German submarine warfare
do you mean what caused us entry into world war one? if so then the sinking of the USS Lusitania by German u-boats was what caused American entry into the war
isolationism
They believed they needed to crush the Allies before American troops arrived.
they believed they needed to crush the allies before american troops arrived.