Answer:
Following the Japanese attack on Pearl Harbor, Congress declared war against Japan; Germany then declared war on the United States.
Step-by-step explanation:
The attack on Pearl Harbor deeply shocked the American people and led directly to the entry of the United States into World War II, both in the theaters of war in Europe and the Pacific. The day after this offensive, December 8, the United States declared war on the Empire of Japan. Internal support in America for non-intervention in the global conflict, which had been strong, disappeared, while clandestine assistance to the United Kingdom was replaced by a full alliance. Nazi Germany and fascist Italy declared war on the United States on December 11, in response to the operations launched against the Asian Axis power.