Here we can find an interesting issue arising:
All politicians and statemen, of all times, from the most ancient eras to the present-day world, sign pacts which are binding for as long as their interests switch. (i.e. Sadam Hussein was at a specific moment a dear ally of the US until conditions changed, becoming thus an enemy of the USA)
Hitler can not be the exception to such rule. He indeed had a pact with Japan, not very clear as to its scope, but the clearest intention, if you will, implied a probable Japanese involvement in the military campaign against the USSR, so the bolsheviks would find themselves forced to wage a two front war.
Unlike history has depicted the facts, Hitler had no interest placed at all across the Atlantic ocean. His fundamental goal was to destroy the soviet communist system and to expand the Reich eastwards.
When december 7th, 1941 came, any possibility for Japan to attack the soviet union in the far east simply dissapeared.
Why did Hitler "honor" his pact with Japan in view of the circumstances?
Isn´t it very odd, Hitler immediately declared a state of war against the USA, in order to remain loyal to an ally (Japan) from who Hitler himself could now obtain virtually NOTHING?
What kind of advantages and military profit could Germany obtain from Japan once Pearl Harbor was attacked? The answer is ZERO.
So why did such a clever stateman such as Hitler proceed in such a foolish manner?
He was no perfect man, for after all, he was human too, but, that kind of mistake?
Didn´t it sound like it was the right moment for the Führer to declare the German-Japanese alliance terminated?
Hitler feared not the US armed forces as such, after all in many engagements the armed forces of the USA suffered tremendous local defeats against the Germans.
It was the geography, size and industrial power of the USA which in the end he accounted. But do not forget, Hitler had no interest at all in the USA.
This, in my opinion, will remain a very dark issue of World War Two.
If Hitler had made it clear to his top officers Germany would never ever wage a war against the USA, why did he declare the war right after Pearl Harbor?
The "Hitler was a very complex mind" argument is not sufficient here.
Since I am not a history researcher, I will certainy continue to have all those questions unanswered.