I wasn't justifying Hitlers decision to declare war, I was simply providing the context in which he made that decision. Its not as if he just woke up one morning and decided to declare war on the U.S., just for the hell of it. There was already lots of tension between Germany and the U.S., and Pearl Harbor gave Hitler the justification he needed to turn it into open war. In retrospect, of course, we can see that this wasn't such a good decision.