I know it's highly unlikely because it's such a small thing, but I find often times I win the game early just by having the most spread out empire and get the most votes in the galactic council. Don't get me wrong it's a good idea but I'd like to be able to turn it off every now and again so I can just demolish the enemy empires and wipe them from the face of the galaxy.

You can, though, as the game doesn't really end, regardless of what happened. You'll just get a victory message on every turn.

You can also choose to defy the council, even if you're the one who won.