Mississippi is violating the federal law that enabled the state to rejoin the union after the Civil War, a civil rights group has alleged in a lawsuit over school funding.

The Southern Poverty Law Center has filed a lawsuit on behalf of four African-American mothers with children in public elementary schools asking a federal judge to force the state’s leaders to comply with the 1870 law, which says Mississippi must never deprive any citizen of the “school rights and privileges” described in its 1868 constitution.

As the report notes, the law requires Mississippi to provide a “uniform system of free public schools,” for all children. The Southern Policy Law Center is accusing Mississippi, however, of repeatedly diluting the education protections of that law ever since, in what they call a “white supremacist effort to prevent the education of blacks,” the Associated Press reports.

“From 1890 until the present day, Mississippi repeatedly has amended its education clause and has used those amendments to systematically and deliberately deprive African Americans of the education rights guaranteed to all Mississippi schoolchildren by the 1868 Constitution,” the lawsuit claims.

The suit names as defendants Gov. Phil Bryant, Lt. Gov. Tate Reeves, House Speaker Philip Gunn and Secretary of State Delbert Hosemann, all Republican elected officials. It also names state school Superintendent Carey Wright and the nine appointed members of the state Board of Education.

The plaintiffs say their children are deprived because they are black and attend overwhelmingly black schools, in districts that have been given an “F” rating by the Mississippi Department of Education.