Why can't people accept that the US is not part of this discussion, yeah we know what happened but for this discussion the US is not available. Maybe for the same top secret reason the US is not available for Syria.
Yes the Soviets and everybody were tired but without the US (or maybe even with?) they'd just have to walk to the coast of France. Island hopping from there might have been too much trouble initially. However, the Soviets could pick up with bombing where the Germans left off.