A few days after the Japanese Attack on Pearl Harbor, Hitler declared war on the United States. The question is: why did he do it? So let’s take a look at what we know. First, his decision to declare war is rather obscure due to the lack of official documents surrounding his decision. So, unless something turns up, we can never know for certain. Yet there’s plenty of information available that gives some insights into his decision. Let’s start with the elephant in the room. No, Hitler didn’t underestimate the United States. He was aware of it’s power and he mentioned it in his unpublished “Second Book”. Where he noted that the power of the United States could only be countered by another country that had the resources of a complete continent available. Although he noted the United States was mostly focused inward. If Hitler was aware of the capabilities of the United States, why did he declare war in 1941? Let’s start at the beginning. Hitler’s rise to power wasn’t well perceived in the United States, and Franklin Delano Roosevelt’s “Quarantine Speech” in 1937 was, according to one of Hitler’s aides, not well received by him. Although there are no specific countries mentioned in the speech, it is directed against Germany, Japan, and Italy. To quote from the speech, “The peace, the freedom, and the security of ninety percent of the population of the world is being jeopardized by the remaining ten percent, who are threatening a breakdown of all international order and law.” What made Hitler so furious, was, that the ten percent meant for him that Roosevelt didn’t portray the Soviet Union as a threat. Nevertheless, since Hitler knew that the United States was powerful and also was backing the British Empire, his approach was to avoid any provocation with the United States for as long as possible. Since he assumed that it was necessary to possess the resources of a complete continent to face off against the United States, his intention was to first defeat the Soviet Union in 1941, and then be ready to engage the United States in 1942 or later. Yet around November 1941 his approach changed. This had a lot to do with the overall situation at that time, which can be broken down into several areas: The Battle of the Atlantic and the shored-off wall policy of Franklin D. Roosevelt, the situation in the Eastern Front, and the uncertainty regarding the intentions of the Japanese. The situation in the Atlantic in 1940 and 1941 was tense. As outlined in my video on the US and German strategy in the Atlantic in 1941, the US escalated the situation several times by expanding operation zones of the US ships, the “Lend Lease Act”, the Destroyer for Bases Agreement, and the announcement that the US fleet would also protect non-US ships in the Atlantic in September 1941. The German Navy at that time wanted to escalate the situation, while Hitler still wanted to keep the United States out of the war for as long as possible, since the invasion of the Soviet Union wasn’t completed. Yet in November 1941, it became apparent that the Soviet Union couldn’t be defeated in 1941 anymore. This situation, furthermore, escalated when in December 1941, just prior to the Japanese attack on Pearl Harbor, the Soviets started a counter-offensive. Basically, the situation in the Atlantic was seen by Hitler and his staff as an undeclared war that limited the operational capabilities of the German Navy. Additionally, Hitler assumed already in December 1940 that the United States would be able to intervene in the war in 1942, and as 1941 showed, there were no indications that Roosevelt would limit his actions in the Atlantic. Which brings us to the final point: the relationship between Germany and Japan. Already, in 1940, the Tripartite Pact between Germany, Italy, and Japan was intended to deter the United States from participating in the war. Yet as 1941 showed, it didn’t work. Hitler assumed that the Japanese were cautious due to fears of a war with the United States or the Soviet Union, thus Hitler gave the guarantee to Japan that it would enter the war on its side if it would be attacked. Although soon after, the Japanese entered negotiations with the United States, which was badly received by Germany, and some even assumed that the Japanese might switch sides. Thus the German intention was to get Japan into the war on the side of the axis as soon as possible. Once the Japanese realized that the negotiations with the United States failed, they tried to get a deal with Germany. Since the Japanese military acted rather quickly, there was no agreement with Germany to enter the war against the United States. Yet when the news of the Japanese attack against Pearl Harbor was received, Hitler was both surprised and quite euphoric. He deemed it crucial to enter the war on the side of the Japanese. Although he didn’t declare war immediately, all restrictions for the German Navy to prevent a confrontation with the US Navy were lifted. The delay of the declaration of war itself was due to the surprise of the German side and thus, the lack of military preparations to conduct operations against the US. To sum it up: First off, Hitler was aware of the power of the United States. Now assuming that his decision was based on the various accounts we have from his aides and officials, it seems that the declaration of war was motivated by the following aspects: First, the perception that the US and Germany were basically at war in the Atlantic. Second, the rather unpredictable stance of the Japanese towards the axis and the allies in the German perception. Third, the assumption that the United States would enter the war in 1942. Thus, the declaration would at least provide some initiative for Germany to engage the United States in a two-front war while the German army would defeat the Soviet Union. Of course, another way to see this situation is that there was not much else Hitler could do at that moment anyway, especially since he assumed that Roosevelt would declare war on Germany in 1942. So in this case, the options for Hitler were so [limited] that the dangerous gamble and the rational decision were quite close to each other. As always, all sources are in the description, as are the links to the Facebook and Twitter accounts. If you liked this video, you might want to take a look at the video on Pearl Harbor, or about the US and German Atlantic strategies. Anyway, thank you for watching, and see you next time.