Third Nacelle wrote:
^Yes, but an Empire isn't really a union of species.
Not necessarily, being joined together doesn't automatically imply that it was voluntary on the part of all parties involved.
The Republic in Star Wars is perfect example of both things happening. It started off as a democratic union of planets.
The senators then gave their chancelor so much power he later used it to simply "reorganize" the republic and make it into an empire.
It was supported by tyranny and violence, yet technically it was supposed to be a republic.