You're a funny fellow. Germany was the more immediate threat, deal with Russia later. Germany would have crushed Russia without our help and then they would have taken us out also..Maybe that outcome sits well with you, but not me.
Why do you believe that?...the German Army was, for all intents and purposes, destroyed after its defeat by the Russians at Stalingrad...and there is no evidence that Hitler or Germany ever had any interest in conquering England or France until September 1939...much less conquering the US...Hitler's desire for Lebensraum was always focused east...Russia and Poland were always his targets
The Nazis had a narrow window during which they could have pushed their advantage of surprise and blitzkrieg to beat the Soviets, but their timetable was thrown off -- by Italy's disaster in the Balkans against the Yugoslav, mostly Serbian partisans.
Having to send in the Wehrmacht to rescue Mussolini's delayed their invasion by several precious weeks (and used up reserves that could have pushed towards Iran's oil fields). These weeks ended up crucial as the German advance bogged down when the Russian winter set in, giving the Soviets the breathing space they needed to call in their reinforcements and Zhukov to lead them...