A challenge to how Republican lawmakers drew legislative districts in 2011 is heading to trial in May.

A panel of three federal judges unanimously ruled Thursday they should decide whether the maps were drawn correctly after holding a trial, rather than based on legal briefs that have already been filed.

The ruling is a victory for the 12 Democrats who brought the case on the theory Republicans had violated their voting rights by drawing legislative districts that are so favorable to the GOP. Those bringing the case hope to set a standard that could be used around the country to determine when politicians — whether Republicans or Democrats — go too far in drawing maps to help them.

Read more at Milwaukee-Wisconsin Journal Sentinel