Trebbi et al. (2008) have observed that (in the US):
Majorities tend to disenfranchise minorities through strategic manipulation of electoral rules. With the aim of explaining changes in electoral rules adopted by U.S. cities, particularly in the South, we show why majorities tend to adopt “winner-take-all” city-wide rules (at-large elections) in response to an increase in the size of the minority when the minority they are facing is relatively small. In this case, for the majority it is more effective to leverage on its sheer size instead of risking conceding representation to voters from minority-elected districts. However, as the minority becomes larger (closer to a fifty-fifty split), the possibility of losing the whole city induces the majority to prefer minority votes to be confined in minority-packed districts. Single-member district rules serve this purpose. We show empirical results consistent with these implications of the model in a novel data set covering U.S. cities and towns from 1930 to 2000.
Is this idea (well, it doesn't seem to have a name, let's call it "Trebbi's law") true in other parts of the world? Or are there substantial counter-examples outside of the US?
I looked at the full text of the paper, but they don't mention any other countries. My own hypothesis is that the level of covert racism (or even just ethnocentrism) in a country/region would be a significant predictor/covariate for where this electorally exclusionary strategy is employed...