@ The Doctor: I think you sound a bit like Kreia. Though they called her a Sith but I think she was neither. She helped yes to provide the Republic with some stability and yes she used the dark side. I think she may have been a perverted version of Jolee Bindo. The last explaination you gave sounds a bit too Sithy like. Maybe it would work like saying that Truth is a Lie after all what is truth, nothing but a certain point of view. What purpose does truth serve if we see everything from our point of view? Truth is nothing more than illusion to create stability and security.
What do you think?