The obvious way to win the game is by eliminating all other civilizations. The more interesting victory condition is by winning a two-thirds majority in the Orion Senate, meaning that two-thirds of the galactic population favors your civilization to rule the galaxy. The Orion Senate appears once two-thirds of the star systems have been colonized, and convenes every 25 years after that until a civilization is chosen or only one remains. Having a large empire and many allies help. However, if the High Council selects a different civilization, it is possible to reject their choice, starting a war of your empire against all.