Replies

That was a deciding factor for sure. However it gets more complicated than that. Remember Hitler helped out by declaring war on the U.S. after Pearl Harbor. That helped out greatly. I am not really sure Roosevelt could have gotten a war decree passed that soon after the Japanese attack. Hitler may have gotten away with it (two front war) if not for the declaration of war blunder. Imagine the U.S. not involved until maybe 1943 or even later. Japan would have been knocked out sooner but no aid to Russia or at least not the amounts we did send. The American public was demanding we knock out Japan. Midway was a great victory but the push to Guadalcanal was due in part to pressure to get on with the war against Japan.
Prior to us coming in we had already agreed that once we got into the war Germany would receive top priority as it was clearly the most dangerous opponent. If we don't get in Russia is probably knocked out and Britain soon after.
Just my opinion and some alternate history which is one of the joys of history. All the tiny what ifs. BTW at Midway the Japanese search plane that located a carrier had a malfunctioning radio and if I recollect correctly launched late due to problems. Little things that turn battles. Of course Japan never had a realistic change to win. There only hope was to wear us down which was never going to happen with the sneak attack screw up. Yamamoto knew that.