Politics of the Regime

Each city of the Regime had its own General Forum and Senate. The former was an assembly of all citizen residents which gathered to direct civic policy across all issues. That policy was then enacted by the City Senate, which was constituted according to protocols set down by the forum at the city's founding. All cities granted senatorial positions to the leaders of the Five Pillars: the high priests, academicians, heads of the noble families, general officers and guild masters. Some then included landowners of a certain scale, others the heads of families of sufficient antiquity regardless of wealth. Whatever the criteria, only citizens could take a seat in the senate.
In addition to civic governance, the Senate formed the city's electoral body. In this capacity, they were responsible for electing three of their number to represent the city in the High Senate of the Regime, and three citizens of any status but good standing to act as civic electors during the election of a new Prime Magistrate of the Regime. Finally, the Senate was responsible for choosing civic magistrates, officials given almost limitless authority to oversee the practical inplementation of specific policies.
Magisterium was the Regime's free-floating executive. Policy was generated by the Forum and enacted by the Senate, but specific practical action was entrusted to magistrates empowered to do whatever was necessary to see the will of the citizenry done. The power of magisterium was a trust, with limited scope and duration to prevent the accumulation of power by any one individual or faction. Of course, these limits were only partially effective. Some dynastic houses or guilds always managed to translate wealth and influence into status and a stranglehold on key magisteria for its members.
Similarly, they High Senate and the Prime Magistrate were intended to check the power of any individual city, although being based in Aeternis, the High Senate was in itself a civic centralisation, especially when the Prime Magistrate - a position intended and empowered to prevent abuses of the other seats of authority - gained a permanent office in the Threefold City, instead of being quartered in the incumbent's home. In addition to oversight, the High Senate and Prime Magistrate were in control of foreign policy and the regiments, the Regime's regular military. They assigned Magistrates Martial to organise and lead the regiments, as well as ambassadors to contact their neighbouring states.