The U.S. Supreme Court is set on Monday to hear a bid by Louisiana officials and civil rights groups to preserve an electoral map that raised the number of Black-majority congressional districts in the state and prompted a challenge by non-Black voters.

A redistricting battle over Louisiana's congressional map has spanned years and been before the Supreme Court twice already.

The case, which centers on whether Louisiana’s congressional districts are an illegal racial gerrymander, tests the leeway that states have in drawing voting maps.