I think this could be one of the "what ifs" in history, but probably one that is unanswerable. A lot would depend on how any coup was handled. It's possible that Hitler could be killed, and the coup still fail. If that happened it might possibly be "business as usual." I'm not sure who would have taken over from Hitler, probably Goering, but Himler or Goebles, (sp?) might have tried to grab power also. If the coup had succeded and all of the top officials were arrested or killed, then there may have at least been offers made to the western powers for a negotiated peace. At that point I'm not sure how well the Allied promise of no seperate peace between the powers would have held up. I can personally see Churhill being all in favor of settling with the Germans, and allowing them to continue the fight agaist the Russians. I can't see Roosevelt doing that though.