Most historians agree that the turning point in World War Two was the battle of Stalingrad. But Germany would not have been defeated if the US had not given the Brits and Russians substantial aid. As the Soviets pushed the Nazis back on the eastern front, they did so while driving Dodge trucks made in Detroit while they ate American made Spam.

It's ironic- Roosevelt gave Stalin thousands of tons of war material, only to have the equipment turned agianst the US after the war ended, as the Cold War began. It would have been very shrewd if the Americans had cut Russia off before the fall of 1944- this would have slowed the Soviet advance into central and eastern Europe, allowing the Western allies a chance to capture Berlin. The "Iron Curtain" would have had different boundaries, the West would have been in a stronger position...I think the fear was that the Germans might unleash a new and terrible secret weapon just as they were collapsing, and thus halt the allied advance. So Roosevelt felt compelled to aid the Russians all the way to the end of the war.

When "what if''s" are contemplated in history (after the fact), this is called a "counter-factual." Do you like the counter factual I just conjured up?