Cleavages, Institutions and the Number of Parties: A Study of Third Wave Democracies

This article evaluates how social cleavages and institutions shape the number of parties in the world’s newest democracies. It supplements existing propositions about the interaction of institutions and ethnic heterogeneity with an argument about the geographic concentration/dispersion of relevant groups. And it reflects on the interaction between institutions such as the electoral system, the form of government, and the relative decentralization of governmental authority. A quantitative analysis leveraging returns collected for 255 elections held in 61 “third wave” democracies reveals that the interaction of ethnic cleavages and institutions is more complex than the existing work suggests. The territorial configuration of ethnic cleavages appears to be decisive to the effect of institutions, while the proportionality of the electoral system seems to work in interaction with decentralization. The findings have important implications for both the science and practice of constitutional engineering.