Who declared war against the British and the Germans?

The United States declared war against Germany on April 6, 1917, during World War I, following a series of provocations, including unrestricted submarine warfare and the Zimmermann Telegram. In World War II, the U.S. declared war on Japan on December 8, 1941, after the attack on Pearl Harbor, and subsequently declared war on Germany on December 11, 1941, following Germany's declaration of war against the U.S.