Gerrymandering takes two main forms. Partisan gerrymandering rigs district lines to benefit one political party, using packing and cracking to engineer electoral outcomes. Packing concentrates opposition voters into a few districts where they win by huge margins, wasting their votes. Cracking splits those same voters across multiple districts so they never have enough support to win any of them. Together, these tactics allow a party to win far more seats than its actual share of voters would justify. Since the Supreme Court ruled in Rucho v. Common Cause (2019) that federal courts cannot intervene in partisan gerrymandering cases, it falls largely to states to address the problem on their own.
Racial gerrymandering intentionally draws district lines based on race, which is unconstitutional under the 14th Amendment. The Supreme Court first recognized this claim in Shaw v. Reno (1993), establishing that districts drawn predominantly along racial lines are subject to the highest level of legal scrutiny. In practice, though, race and party affiliation often overlap, and map-drawers increasingly defend racially discriminatory maps by claiming partisan motivation instead, a loophole the Court has left open.
Understanding Gerrymandering