> The Normandy landings were an irrelevant sideshow. Only important in determining who would rule in europe after the war.

While the Soviets have often been unfairly undermined for their role in the ending of WW2, what you just said is a huge stretch and, frankly, fairly offensive to the other Allied nations that gave their lives in that effort.

Could the Soviets keep running over Europe without the western front? maybe, is the answer; certainly not in a reasonable time frame. As the history of the war showed, the farther armies got away from their supply lines the more vulnerable they were. Just as in Stalingrad, there is nothing to say that Germany couldn't have regrouped and held out in their own position somewhere to amass an army for a major counter attack. And let's not forget Germany was by far technologically superior to the Soviets.

Because the German army had to defend on two fronts there is no possible way they could concentrate their forces in one position and overwhelm either front; especially after the affect that the west air power had against the Luftwaffe.