If you like The Political Machine, you may want to check out Galactic Civilizations, Stardock's award-winning space based strategy game. In it, players take on the role of leader of a United Earth and must expand into a galaxy that is filled with hostile alien civilizations. Players must balance diplomacy, manufacturing might, economic power, and military skill in order to survive and eventually win. The game won editor's choice awards from most of the major PC game publications.
There is also an expansion pack for it - Galactic Civilizations: Altarian Prophecy, which adds additional alien races, custom map support, a campaign, and custom scenarios. It also includes editors to tweak the game in countless ways. Learn more at https://www.galciv.com.