No one wins a nuclear war, not when everyone has them. That is why 'the Great Powers' have not fought each other since the 1950's, at least not directly.
Naturally there will be a few bombing campaigns, supported of questionable right-wing 'benevolent dictators', some mild economic pressure. Maybe even arm a few terrorist groups just to spice things up.
Ahhhhh, those evil Russians. How can they be so evil and do all these things?