Each Subsector beginning late in the history of the Star Imperium saw the appointment of a subsector assembly selected by local governments or populations of individual worlds, at least in theory. The subsector assemblies selected the Sector assembly of each Stellar sector.

However, the large number of populated worlds in several Subsectors (in the tens of thousands) saw the use of computerized random lotteries to select seated assemblypeople. The remainder became unseated assemblypeople, who had the right to petition the local Subsector assembly, but could not vote on local legislative proposals and resolutions nor could they vote to select members of the sector assembly. 95 to 98 percent of candidates for Subsector assemblies became unseated assemblypeople.