Political implications of residential mobility and stasis on the partisan balance of locales

Drawing on movement patterns of several million voters within a six state region across four biennial intervals, we evaluate whether migration patterns are consistent with the thesis that migrants are sensitive to the political balance of destination neighborhoods once we control for the important economic and demographic covariates of relocation. Substantial minorities of the movers we track appear drawn to neighborhoods that are more politically compatible with their party of registration than the ones they left behind. Notably, those who change their party registration upon relocating appear highly sensitive to differences in the political climate between origin and destination. But selective in-migration is not the only, or even the primary, force behind the development of politically one-sided opinion environments. We find evidence based on models for millions of non-movers that out-migration or abandonment is consistent with the entrenchment of single-party politics, just as economically robust areas attract a mix of partisans in search of employment and better housing. Evaluating who remains behind is as important as studying those who leave when we want to learn about the consequences of residential relocation.