Answer:
"Yesterday, December 7, 1941—a date which will live in infamy—the United States of America was suddenly and deliberately attacked by naval and air forces of the Empire of Japan."
Step-by-step explanation:
On December 8, 1941, President Franklin D. Roosevelt addressed the nation in a speech that would become one of the most pivotal and iconic in American history. Mere hours earlier, the United States had suffered a devastating surprise attack by the Imperial Japanese Navy on the naval base at Pearl Harbor in Hawaii.
Though America had up until that point maintained neutrality in the brewing global conflict of World War II, the unprovoked assault on Pearl Harbor would prove to be the catalyst that pulled the slumbering giant into the fray.
In his historic speech, Roosevelt condemned the "date which will live in infamy" - December 7, 1941 - when the Japanese carrier fleet unleashed their assault on the unsuspecting base, killing over 2,400 Americans and severely crippling the US Navy's Pacific fleet.
The visceral reaction of the American public to the heinous and unprompted attack unified the nation and led Roosevelt to make his immortal declaration that the United States could not sit idly by.
The very next day, December 8th, Congress declared war upon the Empire of Japan, officiating America's entry into the deadliest military conflict in human history.
Hope this helps! :)