It seems to me that often political structures are thought to 'work' if they provide legitimacy and hence closure, regardless of whether they optimize decision-making. Examples:
- courts: after paying close attention to a particular court, people sometime opine that the process doesn't seem to be very good at getting the right answer. Yet in American society at large, people don't seem to be particularly bothered by the courts. So the procedure suffices for legitimacy even if people aren't impressed with its decision-making.
- a more extreme case is arbitration, which focuses even more on closure at the expense of getting all of the information
- democratic voting: it seems like having 'the masses' simply vote on things, without any other structure (such as deliberative polling) often does not get 'the right' answer. However it seems to be a stable system; I think because it seems legitimate.