good ideas people, but, consider this. Britain didn't want a World War, neither did France or any of the other allied countries that had participated in the First WW, and the United States wanted no part of it. So, could it have been possible for the allies to turn a deaf ear/eye to the Germans? Maybe they thought that if they attacked first, they would make world war I happen. maybe they thought that if they let things start by others hands, they would not feel that they started it.
the same can be said about WWII. Britain, France and the other Allies didn't want to start another WW, even though, they could have easily squashed Hitler when he started to break the Versailles treaty. Maybe they figured that if they let Hitler take back his precious small pieces of Germany he would stop. Britain and France and America certainly didn't want another WW, less than 20 years after the first.