December 11 is certainly an interesting turning point. I've got a book in my 'read' stack you might find of interest: "Hitler's American Gamble: Pearl Harbor and Germany's March to Global War" by Simms and Laderman. From the back page and flap, it goes into the factors that went into what Hitler considered to be a calculated risk. My progress through that stack has slowed (long story). But the book was news to me when I spotted it, scooped it up.