Once you have obtained commlink frequencies for all factions, you can convene the Planetary Council to vote on planetary policies, including election of a Planetary Governor.
In elections for Planetary Governor (and Supreme Leader), each faction casts votes equal to the total size of all its bases. This total may be modified by faction powers and
Secret Projects. Only the leader of one of the two factions with the highest vote totals may stand for election as Governor or Supreme Leader.
On votes to set planetary policies, each faction receives one vote. In these votes, the current Planetary Governor has veto power, which can be overridden only by unanimous vote of all remaining factions.