Summary of "Voter Migration and the Geographic Sorting of the American Electorate"

This study analyzes the migration pattern of the American electorate. Counties in America tend to be either overwhelmingly Democratic or Republican, and increase in this division as partisan individuals move to places populated with other people of the same political mindset. As evident by the red/blue divide in most electoral maps, Republican counties tend to sprawl across most of the country’s land, while majority Democratic areas often occupy the most densely populated areas, and these authors argue that the pattern of electorate occupation is not random. In fact, partisan migration is often tied to the racial, class, and urban/rural characteristics of the location.

This study examines the data of the internal (within the US) migration patterns of individuals. Migration of individuals to geographic locations that are often homogeneous in terms of ideology tend to reflect national party polarization, creating extremely conservative Republican areas and extremely liberal Democratic areas, often overshadowing the socially liberal Republicans or fiscally conservative Democrats. This study concludes noting that this trend of polarization, or “party sorting” and partisan migration are occurring simultaneously, even if individuals follow this trend subconsciously.

Ultimately, the authors warn that if this migratory trend of polarization based upon individuals' partisan ideology, the country could potentially be torn apart by intolerance toward opposing viewpoints.

 Fig 1. Migration in and out of Portland, Oregon, by political party registration. (Color figure available online.)

Tam Cho, W. K., Gimpel, J. G., & Hui, I. S. (2013). Voter migration and the geographic sorting of the American electorate. Annals of the Association of American Geographers, 103(4), 856-870.