Dilutive Drift: The Racial Impact of Low-Change Maps

As America’s racial composition shifts, states that minimize changes to existing districts in successive redistricting cycles can entrench racial disparities in representation, a process I term ‘dilutive drift’. Using novel spatial measures of U.S. House district change between successive congresses, I show that packing and cracking can occur passively, not only through deliberate gerrymandering. States with long histories of racial exclusion, such as Alabama and Louisiana, make persistently fewer changes to their districts than other states. Minimal-change redistricting, I argue, can entrench unequal representation just as effectively as overt gerrymandering.