Pearl Harbor was the main reason the US joined the war. They declared war on Germany and Japan because Japan bombed Pearl Harbor, and Germany was Japan's ally.
The US was forced to declare war on Japan in DECEMBER 9, 1941
the us didn't declare war on china in world war 2 us declared war on japan on 1941 when japan bombed pearl harbor hawii
Because of Pearl Harbour.
Japan
pearl harbour attack
Pearl Harbor.
December 8, 1941
On Japan.
Declare war on Japan
Reason 1-To help the other countries that were not as techlogical as the us. Reason 2-So that it would end the war all together. Reason 3-to make japan surrender and get peace in the countries.
declare our independence from Britain