In a groundbreaking victory for Arnold & Porter's clients, a panel of three judges in the Wake County Superior Court unanimously struck down North Carolina's state legislative maps as unconstitutional partisan gerrymanders. The court further ordered that the North Carolina General Assembly has until September 18, 2019 redraw the maps, applying strict nonpartisan criteria and in full public view.

In November 2018, Common Cause, the North Carolina Democratic Party, and 37 individual North Carolina voters sued North Carolina's legislative leaders over the partisan gerrymandering of legislative maps for both chambers of the North Carolina General Assembly. The lawsuit, which was filed in the Wake County Superior Court, challenged the 2017 redistricting plans as violating the North Carolina Constitution and sought to establish new, fair state House and state Senate maps for the 2020 elections. 

On September 3, 2019, the court concluded in a 357-page decision that the maps violate the North Carolina Constitution's clauses guaranteeing free elections, equal protection under the law, and freedom of speech and assembly. 

In a separate victory for Arnold & Porter clients in the high-profile gerrymandering lawsuit, League of Women Voters of Pennsylvania v. Commonwealth, the Pennsylvania Supreme Court similarly cited provisions of its state constitution in striking down its state congressional map in January 2018.