The bombing of Pearl Harbor surprised even Germany. Although Hitler had made an oral agreement with his Axis partner Japan that Germany would join a war against the United States, he was uncertain as to how the war would be engaged. Japan's attack on Pearl Harbor answered that question. On December 8, Japanese Ambassador Oshima went to German Foreign Minister von Ribbentrop to nail the Germans down on a formal declaration of war against America. Von Ribbentrop stalled for time; he knew that Germany was under no obligation to do this under the terms of the Tripartite Pact, which promised help if Japan was attacked, but not if Japan was the aggressor. Von Ribbentrop feared that the addition of another antagonist, the United States, would overwhelm the German war effort.
But Hitler thought otherwise. He was convinced that the United States would soon beat him to the punch and declare war on Germany. The U.S. Navy was already attacking German U-boats, and Hitler despised Roosevelt for his repeated verbal attacks against his Nazi ideology. He also believed that Japan was much stronger than it was, that once it had defeated the United States, it would turn and help Germany defeat Russia. So at 3:30 p.m. (Berlin time) on December 11, the German charge d'affaires in Washington handed American Secretary of State Cordell Hull a copy of the declaration of war.
That very same day, Hitler addressed the Reichstag to defend the declaration. The failure of the New Deal, argued Hitler, was the real cause of the war, as President Roosevelt, supported by plutocrats and Jews, attempted to cover up for the collapse of his economic agenda. "First he incites war, then falsifies the causes, then odiously wraps himself in a cloak of Christian hypocrisy and slowly but surely leads mankind to war," declared Hitler-and the Reichstag leaped to their feet in thunderous applause.