When did the United States formally declare war on Japan, entering World War II?

The United States formally declared war on Japan, entering World War II, on December 8, 1941. This declaration came just a day after the infamous attack on the naval base at Pearl Harbor in Hawaii, which was carried out by Japanese forces on December 7, 1941. The attack resulted in significant loss of life and destruction of American military assets, prompting the United States to respond swiftly and decisively by officially declaring war on Japan.