Is rising partisan geographic segregation driven by voters moving apart?
Core argument: Using residential location and migration data for 212 million voters in U.S. states recording partisan registration between 2008 and 2020, the authors find residential segregation between Democrats and Republicans rose year over year at every geographic level, from neighborhoods to Congressional Districts.
Using data on the residential location and migration for every voter in U.S. states recording partisan registration between 2008–2020, we find that residential segregation between Democrats and Republicans has increased year over year at all geographic levels, from neighborhoods to Congressional Districts. We decompose the change in segregation into different sources. In Democratic trending places, the most impactful factors are the transformations of the American electorate: influxes of new Democratic-leaning young voters and older first-time registrants replacing voters who are dying or de-registering. In Republican areas, forces of partisan realignment are the most prominent factor driving partisan segregation: voters leaving the Democratic party and registering as Republicans or unaffiliated. Thus, rising geographic polarization is less about Democrats and Republicans fleeing from each other and more about macro-level forces shaping the types of people each party represents and the demographic composition of the U.S. electorate.






