Political science seems to be going through a phase of questioning the rationality of voters. The two major theories of public choice -- Median Voter theory[1] (political parties take positions that appeal to the median voter) and Investment theory of Party Competition[2] (parties take positions most beneficial to their donors), both assume emotions (irrationality) of voters to be small. In the current political clim…
> Median Voter theory [...] political parties take positions that appeal to the median voter
That only seems to work in voting systems with proportional representation (as opposed to first past the post systems).
The latter seem to promote polarization, and this alone seems to explain a lot of the differences between the US/UK and countries with proportional-representative systems.