A gerrymander foiled in Ohio? Reform advocates see a new model.

In recent years, citizen-led efforts to change how states set boundaries for legislative districts have largely focused on the creation of nonpartisan commissions. The idea was to take politics, and politicians, out of the decennial process so that mapmakers could focus on fairness and curb gerrymandering – the delineation of districts for partisan gain. 

Ohio took another path. 

A redistricting commission made up of politicians from both parties draws the lines for Ohio’s state legislative seats, while lawmakers in the Statehouse decide on congressional maps. But there’s a catch: The...