Comment by dragonwriter

> But in better circumstances, there is enormous social pressure (at least on mainstream parties) to be much higher functioning, and willing and able to lead the nation toward a positive future.

No, there isn't, and comparative study of democracies has shown that there is a pretty direct relationship between effective degree of proportionality and a wide range of positive democratic outcome measures, as well as producing a richer national dialogue.

A two-party system doesn't just break down into an us-v-them negative dialogue in bad conditions (it pretty much gets permanently stuck there because it works in a two-party system, and it is consistently easier than deepe discussion of issues), it also narrows the space of of potential solution sets that are even available for discussion to an approximation of a one-dimensional space. Multiparty proportional systems leader to a search space with greater dimensionality, as well as making “well, they are worse” politicking generally ineffective.