Keep in mind, The Soviet Union had a "non aggression pact" with Nazi Germany right up untill the moment "Operation Barbarosa" started.
The fact that Hitler ignored his Generals and insisted on a two front war was what really brought the Nazis to their knees.
Has any body ever thought what the real policy of The United States was during 1944. While not official, it can be said that the policy (as proven by our actions), was: "We are willing to kill every last citizen of the Axis Power Countrys if that is what it takes to achieve victory".