A lawsuit backed by Eric Holder’s National Democratic Redistricting Committee was filed in Mississippi Thursday challenging the state’s system of electing governors and other statewide office-holders. The system requires that the winner receive a majority of statewide votes but also a majority of votes in a majority of house districts — with the Mississippi House deciding the election if no candidate clears both of those bars. The lawsuit, filed in federal court, alleges that the segregation-era system — under which no African American has been elected to statewide office despite Mississippi having the highest percentage of African Americans in the country — amounts to racial discrimination.