The Culture is explicitly a direct democracy, it's just that the books are mostly about what is effectively a somewhat-rogue intelligence agency's activities in other civilizations.
> Politics in the Culture consists of referenda on issues whenever they are raised; generally, anyone may propose a ballot on any issue at any time; all citizens have one vote. Where issues concern some sub-division or part of a total habitat, all those - human and machine - who may reasonably claim to be affected by the outcome of a poll may cast a vote. Opinions are expressed and positions on issues outlined mostly via the information network (freely available, naturally), and it is here that an individual may exercise the most personal influence, given that the decisions reached as a result of those votes are usually implemented and monitored through a Hub or other supervisory machine, with humans acting (usually on a rota basis) more as liaison officers than in any sort of decision-making executive capacity; one of the few rules the Culture adheres to with any exactitude at all is that a person's access to power should be in inverse proportion to their desire for it. The sad fact for the aspiring politico in the Culture is that the levers of power are extremely widely distributed, and very short (see entry on megalomaniacs, above). The intellectual-structural cohesion of a starship of course limits the sort of viable votes possible on such vessels, though as a rule even the most arrogant craft at least pretend to listen when their guests suggest - say - making a detour to watch a supernova, or increasing the area of parkland on-board.