Los Angeles County is suing over a new law it says discriminates against more than 1 million voters.
The lawsuit aims to block a 2016 California law that creates a 14-member commission to draw boundaries for county supervisors' districts after the 2020 census.
The suit says commission members would be chosen from political parties, unfairly excluding about a quarter of county voters who register with no party preference.
Aides to Democratic state Sen. Ricardo Lara of Los Angeles, who wrote the law, counter that the intent of SB958 is to include independent voters.
The suit filed Monday also says SB958 illegally takes away local control.
The suit says that based on current registration, 70 percent of commissioners would be Democrats, 25 percent Republicans and 5 percent from smaller political parties.