On July 5, 2023, the New Mexico Supreme Court ruled in Republican Party of New Mexico v. Oliver that partisan gerrymandering violates the Equal Protection Clause of the New Mexico Constitution. This case challenges the state’s congressional map, which legislators approved in 2021. The New Mexico Supreme Court adopted U.S. Supreme Court Justice Elena Kagan’s three-part test from her Rucho v. Common Cause dissent as its new partisan gerrymander standard. The state Supreme Court remanded the case to the trial court to determine whether the congressional map passes constitutional muster.
Common Cause New Mexico, the League of Women Voters of New Mexico, and the Election Reformers Network joined social science experts to file an amicus brief on August 14, 2023 in the trial court. The brief does not support either party but provides guidance to the trial court about the various tools it can use to determine whether a voting map is unlawful.