What was the significance of the attack on Pearl Harbor during world war 2

It brought the USA into a war that up till now they were trying to stay out of. It also caused the creation and use of the first nuclear bomb

The attack deeply shocked the American people and led directly to the entry of the United States in 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. The internal support in North America for the non-intervention in the world conflict, which had been strong, disappeared, while the 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 operations launched against the Asian power of the Axis.