The Confederation is ruled by a peculiar form of oligarchy.
The Grand Masters are the supreme oligarchs, and can overrule all other governance, each ruling one prinicipality. One might think that this would offer stability and direction to the state, but the Grand Masters seem primarily to be concerned with more transcendent matters (the exception being Valdemar and his holy war on Clemencia). The Grand Masters function more as a constant source of disruption, showing up and making demands on the state coffers, or promoting and demoting people arbitrarily.
The continuous supremacy of the Grand Masters keeps the Confederate politics non-dynastic.
The Senate has 216 seats and 174 elected members. 5 of the seats are reserved for Grand Masters, 36 were left empty after Nicana's destruction. Only sorcerers of magister rank or greater may be elected to the Senate. Senators serve for a decade.