Following The Great Human War in 2267, in which life on Earth nearly ended, there stood one governmental organization and two corporations:
The United Solaris Nations governs around two thirds of the human population, and has since the end of the war. Its military, Solar Space Command, has spread and grown so far since The Great Expansion that its current structure includes a diplomatic branch, treasury, judicial and the main military branch, which takes the role of executive, and the SSC has become adept at all of the missions it has assigned been assigned.
Rexcorp is a megacorporation whose main exports are Bioware and Synthetics (semi sentient computers used by most human intergalactic ships)
Tembibia, the other State-like megacorporation, deals in energy mainly, and is heavily invested in agriculture, terraforming and food export/import. (they are also rumored to have less public branches dealing in the slave trade, though all Sentience has outlawed the practice)