Intereting hypothetical question. One amusing aspect is the idea of Hitler, with his long track record of breaking treaties and of attacking other countries without warning, expressing shock over Japanese treachery – though I guess it’s not unimaginable, since the same track record basically shows that he was quite capable of changing his foreign policies in any way that he felt served his interests at any given time. And relations between Germany and Japan were not always cordial. For instance, Germany supposedly expressed shock over the Rape of Nanking and offered itself as a mediator between China (with whom I think it had a degree of military advisory relations) and Japan. And Japan was highly annoyed when Germany signed the August 1939 nonaggression pact with Japan’s old enemy, Russia.
Even taking Hitler’s impulsive and erratic nature into account, however, it’s pretty hard to fathom why he’d declare war on Japan in December 1941. The two countries were partners under the Tripartite Pact, whose bottom line was, frankly, that Germany and Japan agreed to stay out of each other’s way as each nation pursued its expansionist policies on opposite sides of the globe. A war between the two countries, even if it had been declared, would have been virtually impossible to wage since German and Japan were separated from each other by vast stretches of land (notably the USSR, which was unfriendly to both countries) and ocean.
It’s even harder to fathom why Hitler would offer support to the US in December 1941, since the Americans were actively supporting its enemy Great Britain. I can understand Britain’s wartime partnership with the USSR against Germany, on the principle that “the enemy of my enemy is my friend”, but Hitler’s support of the US would have been a case of “the friend of my enemy is my friend”, which makes no sense.
Just for argument’s sake, however, I’d guess that if Hitler had inexplicably offered to the US a wartime alliance against Japan, the Americans wouldn’t have accepted it. Nazi Germany was, to put it mildly, neither liked nor trusted by the Roosevelt administration, and its reaction would probably have been to treat a partnership proposal from Hitler like the offer of a bottle of poison.
it’s pretty hard to fathom why he’d declare war on Japan in December 1941.
I don’t want to speak for Gargantua. But it’s possible that the goal of this declaration of war would be for Germany to distance itself as much as possible from Japan’s Pearl Harbor attack. The underlying objective would be to make the political climate in America less favorable for going to war against Germany.
Nazi Germany was, to put it mildly, neither liked nor trusted by the Roosevelt administration, and
its reaction would probably have been to treat a partnership proposal from Hitler like the offer of a bottle of poison.
The goal of Stalin’s foreign policy was to foster war between Germany and the Western democracies. Stalin hoped to achieve this goal by promoting “anti-fascism.” The Soviet Union would stay neutral in this hoped-for war. This war would weaken both Germany and the Western democracies. Ideally it would be like WWI, and bleed both sides white. That war would set the stage for Soviet expansion westward into Europe. The first stage would be at the expense of Germany and Eastern Europe. The second state would be at the expense of France and possibly other Western democracies.
FDR was extremely eager to embrace the pro-Soviet, anti-fascist foreign policy Stalin envisioned for Western democracies. I don’t see anything Hitler could have done to change that. He didn’t begin to have the kind of penetration into the FDR administration Stalin had. Nor was there any readily available way for him to achieve that penetration. FDR hated Nazis and other Germans, but was very intrigued by communism and by Stalin. It was this mindset which allowed a number of outright communists to achieve positions of great influence in his administration, while anyone with right wing views was either excluded entirely or eased out of any real policy-setting role.
But FDR did not work in a vacuum. Had it been up to him, the United States would have declared war on Germany back in the '30s. The fact it did not do so was because due to strong isolationist forces. While FDR and his allies in the media were working diligently to weaken those forces, even by December 1941 they were still strong. Had Germany declared war on Japan in December '41, it would have been a clear, simple statement. Even FDR and his allies would have found it difficult to distort that statement into something which made war with Germany seem necessary.
By the time of the Pearl Harbor attack, the American pro-war faction had built up too much political momentum for a German declaration of war against Japan to stop them. Sooner or later, the pro-war faction would succeed at getting America into the war; much like it had succeeded in WWI. Even over the short-term, the pro-war faction would still have been able to send large quantities of weapons to Stalin and the Soviet Union, as well as to Britain.
Let’s say that declaring war against Japan would have bought Germany two years of nominal peace with America. While Germany would still have had to deal with large numbers of American made weapons during that two year period, at least it wouldn’t have had to face American soldiers. That two year grace period would have allowed Germany to concentrate more of its military force on its eastern front, instead of having to use as much strength defending against potential or actual Anglo-American invasions elsewhere. (Though they would still have had to defend against the Anglo half of that threat.)
That concentration of force against the Soviet Union would undoubtedly led to a more favorable situation on Germany’s eastern front. More victories, more Soviet soldiers captured, more conquered Soviet land. But I do not think that this alone would have been sufficient for Germany to win the war in the east. In the absence of other factors helping Germany, the German objective on the eastern front should (in this scenario) have been to grab what land it could in the western U.S.S.R., including at least some of the Caucasus oilfields, and then negotiate peace with Stalin. The more successful Germany was on its eastern front, the more presumptively likely Stalin would have been to negotiate an end to hostilities.
This peace treaty would by no means have represented the end of the war. It would merely indicate Germany had survived the first phase of the challenges ahead of it.