Gerrymandering is drawing electoral district lines to favor one party or group. The name comes from Massachusetts Governor Elbridge Gerry, who signed off on a district in 1812 that critics said looked like a salamander. Mapmakers use two main tactics: "packing" a group's voters into a few districts and "cracking" them across many so they cannot form a majority.
Racial gerrymandering has a long history. In Gomillion v. Lightfoot in 1960, the Supreme Court struck down Alabama's redrawing of Tuskegee's boundaries into a 28-sided shape that removed nearly all Black voters. The Voting Rights Act of 1965, as applied in Thornburg v. Gingles in 1986, requires states in some circumstances to draw districts where minority voters can elect their preferred candidates. In Allen v. Milligan in 2023, the Court upheld that rule and ordered Alabama to draw a second Black-opportunity district.
Partisan gerrymandering is harder to challenge. In Rucho v. Common Cause in 2019, the Supreme Court ruled that federal courts cannot hear partisan gerrymandering claims. Because race and party are closely linked in many states, partisan maps can dilute the power of voters of color. Some states have shifted line-drawing to independent redistricting commissions.