Thankfully I had a history professor, Herbert Hamm, in college that loved diving into the less taught perspectives of American history. His thoughts on the driving force behind Pearl Harbor included similar details not taught in the run of the mill American history classroom. His views on the Civil War and Emancipation Proclamation would have him lose his tenure these days.I know it's a really unpopular view, but if you look at Japan pre-1930 and see what they were doing (trying to emulate the United States) - it's easier to understand why they felt justified in invading China, and claiming so much territory for their own.
United States hegemony in the Philippines and the general area had been a shining example for what could be achieved by a superior force. Turns out the United States doesn't like competition, and things escalated from there.
I state none of this to justify Nanking or the treatment of prisoners by the Japs. I do state it to remind folks that Pearl Harbor wasn't just dreamed up overnight, it wasn't a surprise to FDR, and the Japanese aren't the only nation that decided to violently take control of the Pacific.