Score contribution per author:
α: calibrated so average coauthorship-adjusted count equals average raw count
A party’s influence over redistricting increases discontinuously when its seat share in the state legislature exceeds 50%. We apply bunching tests to show that, in the election before redistricting, parties systematically win narrow majorities in legislatures of states where they have lost recent U.S. House races. This trend of losses is reversed after redistricting despite no change in overall House vote shares in states near the cutoff. The pre-to-post-redistricting change in regression discontinuity estimates implies that the party that controls redistricting engineers an 11 percentage point increase in its probability of winning a House race.