New paper from Jonathan Cervas (Carnegie Mellon), Bernard Grofman (UC-Irvine), Scott Matsuda (NYLS), and Justine Kawa (NYLS), Partisan Gerrymandering Cases in State Supreme Courts in the 2020s Redistricting Round. The abstract:

After the U.S. Supreme Court opted out of any federal court role in policing partisan gerrymandering in its 2019 decision, Rucho v. Common Cause, if a redistricting plan was alleged to be a partisan gerrymander, that challenge needed to be brought in state courts. There are three possibilities: (a) a state supreme court could hold partisan gerrymandering claims nonjusticiable under state as well as federal law; (b) it could review a proposed map and find it unconstitutional; (c) it could review a map and reject the gerrymandering claim. Here, we focus on state court decisions that took place before the November 2022 elections in partisan gerrymandering claims regarding maps drawn for elections to the U.S. House of Representatives in the 2020s redistricting round. We are primarily interested in three issues: (1) How did state courts faced with a redistricting challenge based on a claim of partisan gerrymandering decide whether state law allowed them to address the factual aspects of the claim rather than treating the claim as non-justiciable? (2) If the court decided the claim was justiciable, what definition of partisan gerrymandering was used and, in particular, what kind of empirical evidence was cited by the justices – e.g., measuring the extent of gerrymandering via metrics based on election data, and/or evaluating maps in terms of the degree to which traditional good government criteria were satisfied, and/or considering the process of map drawing and what it implied about partisan intent? (3) Is there indirect evidence that the partisan predilections of the justices affected their decision about the constitutionality of a challenged congressional map?