Following the Declaration of War on Japan on December 8, 1941, the other Axis nations of Germany and Italy declared war on the United States. Congress responded, formally declaring a state of war with Germany in this Joint Resolution on December 11, 1941.
More about the outbreak of war at Our Documents…

From Prologue: "FDR’s ‘Day of Infamy’ Speech: Crafting a Call to Arms"

Today’s Document from the National Archives