German Declaration of War against the U.S. - 12/11/1941. Anonymous on Jun 13, 2007WTF is a declaration of war. Anonymous on Jun 13, 2007Hmmmm, Yes. Anonymous on Jun 13, 2007Another Dumbass know it all. When did germany attack us? on Jun 13, 2007On Dec 7th 1941 by default.. you guys obviously flunked history on Jun 13, 2007