The Cold War is a time period lacking in almost all real-time strategy games - hell, I can't think of any in actual fact, in any genre. The closest you ever get is Soviet based WW2 games. Company of Heroes is great, albeit not quite what you're looking for.
There is one I remember, world in conflict, that was fun.
Another that I've heard of but not played is the wargame series, which I think is set a bit further back in the cold war than world in conflict.
Both alt-history obviously.
