Declaration of War

On Sunday, December 7, 1941, naval forces of the Empire of Japan attacked U.S. military installations on the Island of Oahu, the U.S. Territory of Hawaii, killing 2,403 American servicemen and wounding 1,178 others.  In addition, eighteen U.S. naval vessels were sunk or damaged.  As a result, the following day, Monday, December 8, 1941, U.S. President Franklin Delano Roosevelt (FDR) asked for and received a near unanimous Congressional Declaration of War against the Empire of Japan.

Three days later, Thursday, December 11, 1941 (76 years ago tomorrow), Nazi Germany declared war on the United States without any similar provocation. Hours later that same day, the United States reciprocated and declared war on Nazi Germany. (The last U.S. Declaration of War was on June 5, 1942 against Nazi German allies Bulgaria, Hungary and Romania.)  So why did Germany declare war on the U.S.?

In its declaration of war, the Nazi government accused the U.S. of violating the rules of neutrality in favor of Germany's enemies, of attacking German military vessels and of seizing its merchant ships.  Such incidents started occurring at the beginning of the war in Europe in September of 1939. So why the delay of more than two years until December 11, 1941?

In Berlin, on September 27, 1940, Japan, Germany, and Italy signed an agreement known as the Tripartite Pact.  In Article 3, the three countries agreed to "assist one another with all political, economic and military means if one of the contracting parties is attacked by a power at present not involved in the European War or in the Japanese-Chinese conflict."  The power they were referring to was the United States.  

At the beginning of December of 1941, the Japanese ambassador to Germany, Baron Hiroshi Oshima, informed German Foreign Minister Joachim von Ribbentrop that war was imminent between Japan and the United States.  He asked for German assurances that it would declare war on the U.S. under the terms of the Tripartite Pact.  However, Japan attacked the U.S., not the other way around which would have fallen under the terms of the above Pact.  

In spite of Nazi Germany's involvement militarily on multiple fronts against the USSR and the UK, Hitler unilaterally decided to declare war on the U.S.  One reason was "Hitler's deeply held racial prejudices made him see the U.S. as a...people of mixed race, a population heavily under the influence of Jews and Negroes, with no history of authoritarian discipline to control and direct them. Such a country could never be a serious threat to a country like Germany."

Perhaps Hitler felt personal animus towards FDR.  He said, "Roosevelt comes from a rich family and belongs to the class whose path is smoothed in the democracies.  I was the only child of a small, poor family and had to fight my way by work and industry."  

Perhaps Hitler felt FDR to be his political rival.  They both came to power at almost the exact same time, in March of 1933.  According to the author, Doris Kearns Goodwin, Hitler contended that the American president had provoked the war to cover up the failures of his New Deal. Hitler claimed, "This man (FDR) alone was responsible for the Second World War."
  
According to the economist John Kenneth Galbraith, who worked in the Roosevelt Administration during WWII, "It was truly astounding when Hitler declared war on us three days later.  It was a totally irrational thing for him to do."  Whatever the reasons, the U.S. was now involved in a two-theater world war that would last for three years and eight months before victory was won.