If Germany attacked and great Britain Russia and France were to fall which would of happened if hitler wasn't stupid America most likely would not have won Japan would have the navy which Would be a crazy navel battle but Germany had more advanced weapons more advanced tanks the Sherman is no were near able to kill a panzer and the Luftwaffe were very experienced fighters while I love America during world war 2 if hitler wasn't so stupid our future wouldn't be to bright
The better question is why didn't Japan continue Eastward after Pearl Harbor? They would have been unopposed to the California coast and we didn't have our 'war machine' even thought of! That was far more plausible than Germany making it.
Hitler had no such intentions. He knew he couldn't fight a transoceanic war. Germany lacked the shipping and port capability to support such a conflict. The Reich feared rousting America from neutrality, and their defeat became inevitable once the US entered the war.
That makes me wonder why FDR got us involved in that war. Japan I can see they invaded us. He was just possibly another George W. We should have waited until they invaded us. Peeking at us from U-boats was just voyerism.