Citizens’ ideology drives ideological polarization and partisanship in U.S state legislatures

The increasing partisanship and polarization present Congress has been subject to a great deal of study and many explanations as to its causes have been put forward. Justin H. Kirkland takes a different line in investigating polarization, by looking at how it varies between state legislatures. Using survey and roll call vote data from across the country, he argues that in those states with more ideologically disparate populations, legislative districts will become more extreme as people sort into them. This in turn will lead to their legislators expressing a higher degree of partisanship in the state legislature.