Who is My Neighbor? The Spatial Efficiency of Partisanship
46 Pages Posted: 25 Aug 2017
Date Written: August 23, 2017
Relative to its overall statewide support, the Republican Party has been over-represented in Congressional delegations and state legislatures over the last decade in a number of U.S. states. A challenge for courts is to determine the extent to which this can be explained by intentional gerrymandering vis-a-vis an underlying inefficient distribution of Democrats in cities. We explain the problem of spatial inefficiency in partisan support, and measure it by borrowing from the field of plant ecology, assessing the partisanship of the nearest neighbors of each voter in each U.S. state at the spatial scales relevant for Congressional delegations and both chambers of state legislatures. We demonstrate that as a result of urban-rural partisan polarization, much of the cross-state and cross-chamber variation in Republican advantage can be explained by the relative spatial inefficiency of Democrats. Moreover, our pure political geography approach to votes and seats provides a useful baseline against which to evaluate claims of partisan gerrymandering. We demonstrate that Republicans are often able to improve significantly on their underlying geographic advantage when they control the redistricting process, while Democrats are sometimes able to ameliorate it when they draw the lines.
Keywords: gerrymandering, redistricting, representation
JEL Classification: R50
Suggested Citation: Suggested Citation