California Republicans filed a federal lawsuit on Wednesday seeking to block a newly approved U.S. House district map that voters in the state supported through Proposition 50. The measure, backed by Democratic Governor Gavin Newsom, is expected to help Democrats flip up to five congressional seats in the 2026 midterm elections.

The lawsuit, submitted to the U.S. District Court for the Central District of California, alleges that race was improperly used in drawing the congressional boundaries, giving an electoral advantage to Hispanic voters. The plaintiffs argue this violates both the 14th and 15th Amendments of the U.S. Constitution.

The legal challenge comes from The Dhillon Law Group, founded by Harmeet Dhillon, now a senior civil rights official in the U.S. Department of Justice. Mike Columbo, the attorney representing 19 plaintiffs—including a Republican state lawmaker—argued the redistricting plan unfairly prioritizes one racial group over others.

Governor Newsom’s office, responding via social media, dismissed the lawsuit, suggesting it would not succeed.

The timeline for resolving the lawsuit is critical, as potential candidates for the 2026 elections can begin collecting signatures on December 19 to reduce filing fees. Columbo expressed hope for a ruling within weeks, although previous GOP challenges to California’s redistricting efforts have seen limited success.