Supreme Court establishes three-part Gingles test for Section 2 redistricting claims

The Supreme Court issues its landmark ruling in Thornburg v. Gingles on June 30, 1986, establishing the three-part test that governs all Section 2 vote-dilution redistricting challenges for the next 40 years. Justice William Brennan writes that a minority group can prove vote dilution under Section 2 if it shows: (1) the group is large enough and geographically compact to form a majority in a single district; (2) the group is politically cohesive; and (3) the white majority typically votes as a bloc to defeat the minority's preferred candidate. The ruling strikes down North Carolina's multimember legislative districts for diluting Black voting power and creates the legal framework that will require dozens of states to draw majority-minority districts in the 1990 redistricting cycle.