In April 2026, the U.S. Supreme Court issued the Louisiana v. Callais decision, weakening the Voting Rights Act (VRA). We estimate the effects of Callais on minority representation and electoral competition in the U.S. House under two scenarios: (1) congressional districts are drawn in a race-blind, nonpartisan manner without complying with the pre-Callais VRA, and (2) both parties pursue aggressive partisan gerrymandering without former VRA protections. Using state-of-the-art redistricting simulations that satisfy traditional redistricting principles and state-specific criteria, we evaluate the effects of Callais. We find that, in aggregate, the pre-Callais VRA produced aggregate levels of minority representation similar to race-blind nonpartisan redistricting, suggesting it conferred little partisan advantage. Under aggressive gerrymandering, however, Callais is likely to benefit Republicans while reducing minority representation, particularly in Southern states with large, geographically concentrated Black populations. It also further reduces electoral competition by 24 House seats, on average.

redist: redist: Simulation Methods for Legislative Redistricting — CRAN / GitHub