Originally Posted by Si

If it were not for Russia and America? You Americans joined about 3 years into the battle! Only because the Germans were up and down your water ways blowing up your ships did you decide to join in fully.

Originally Posted by wiki

The attack came as a profound shock to the American people and led directly to the American entry into World War II in both the Pacific and European theaters. The following day (December 8), the United States declared war on Japan. Domestic support for isolationism, which had been strong,[14] disappeared. Clandestine support of Britain (for example the Neutrality Patrol) was replaced by active alliance. Subsequent operations by the U.S. prompted Germany and Italy to declare war on the U.S. on December 11, which was reciprocated by the U.S. the same day.