I just have five words as a bit of foreshadowing and difference from canon. The Coalition of Democratic States.
The Soviets would get grumpy if they weren't included (and they and the States were pretty much as close as you could come to BFF by Aftershocks, even if just through self interest) and if they were then it would be easy for the Race and the Nazis to make a mockery out of it. I really don't see the need to go against the books anyways, we could make an interesting scenario without having to change any established canon.