Do Redistricting Principles and Practices Affect U.S. State Legislative Electoral Competition?

Abstract

Critics of U.S. congressional and state legislative redistricting have argued that gerrymandering severely undermines electoral competitiveness to the point of violating constitutional equal protection standards. In this article, we evaluate whether redistricting principles and processes have any measurable consequence on state legislative electoral competition. In addition to their substantive importance, state legislative general election contests provide greater variance than congressional data for empirically assessing theoretical propositions regarding redistricting principles and processes. We find that electoral competitiveness in state legislative races declined throughout the 1990s, even after term limit reforms were implemented. The proportion of uncontested state legislative seats has doubled since the 1970s, and there has also been a slight increase in average margin of election district victory. Our results show that political principles and some traditional, “politically-neutral” redistricting principles significantly decrease the probability of uncontested state legislative elections. In contrast, independent redistricting commissions did not appear to affect state legislative competition. We conclude with a discussion of how our findings relate to the redistricting reform debate.