Heavily disagree, but I think someone else already said it better than I:1. Each Power should Stand Alone, regardless of what Superpower they support*, as they are not the same power, or they wouldn't exist.
As for common sense? Let's take the Federation.
Hudson is President. Winters is Shadow President. Winters may be representing the Opposition to Hudson on a political level, but that wouldn't mean she would actively undermine the interests of the Federation as a whole by sabotaging and attacking Hudson in favour of their common enemy - the Empire.