I don't think America COULD have stayed out of it completely. If we had not involved ourselves, Germany and Japan would have eventually put the squeeze on us as they would have controlled both oceans and the majority of the world's resources. It would only have been a matter of time before they forced our hand.
Speaking of forcing hands, we need to remember in a sense, that's what we did to Japan. Our sanctions on resources to them pushed them to the brink.
Some really fun reads on alternative history are by Harry Turtledove. He has written two about the "what if's" of Japan following up the bombing of Hawaii with an invasion force.
He has several about Europe in WWII and has some really good books on the Civil War. His alternatives to the Civil War is not a North South, but an East West where Canada and Mexico are putting an international agressiveness to it as well.
Very good reads.
\"HABU\" FFR 3817 Redfire w/ Silver Stripes Stock build w/ 3:73\'s/Mass=Flo/Dual Roll Bars/Street Performers(finished 28 Feb 2004)