The Intentional Use of Incumbent Residences as a Form of Gerrymandering

• In Event: Redistricting and Representation

Abstract

State legislators in the United States are required to reside in the district they represent. This has major implications for redistricting, since the boundaries of their districts can be altered to move the residences of incumbent legislators into districts occupied by other incumbent legislators. As a result, a redistricting party can effectively eliminate incumbent legislators of the opposing party by intentionally pairing them in the same districts. But to what extent does this actually happen? Do parties design districts to strategically pair incumbent legislators? Using legislator addresses derived from voter registration files, I assess incumbent pairings in senate districts enacted during the 2021 redistricting cycle in 27 states with unified partisan control. I find that these redistricting plans paired only about 14% of incumbent senators, which is remarkably small compared to 46% of incumbent senators paired in the average alternative plan drawn by an incumbent-blind computer. The relatively small number of pairings is evidence that mapmakers are intentionally protecting incumbents from incumbent challengers. This protection appears to exist across all states, with the exception of Iowa, where redistricting law prohibits the use of incumbent addresses. Moreover, this protection seems to advantage the mapmakers' party when districts are competitive.

Author

• David Cottrell, University of Georgia