Gerrymandering

Redistricting is the process of changing electoral district boundaries, often after population counts require seats to be redistributed or districts to be adjusted. Gerrymandering refers to manipulating those boundaries to advantage a party or weaken the electoral influence of a group. The term is most closely associated with partisan districting in the United States, though debates about how constituencies are drawn arise in other political systems as well.

District maps must also account for population, geography, legal requirements and decisions about which communities should be represented together. Consequently, uneven or irregular-looking boundaries are not, by themselves, proof of gerrymandering. Conversely, a map can favor a party even if its districts look compact and orderly. Evaluating a particular map requires evidence about its design, the applicable rules and its likely effects—not just its appearance.

Two commonly discussed methods are packing and cracking. Packing concentrates a group of voters in a small number of districts, where its candidates may win by large margins, while leaving fewer districts in which that group can influence the outcome. Cracking divides the group's voters among several districts so they are too small a share of the electorate to elect their preferred candidates in any of them. A map may use both techniques.

These terms describe how boundaries can alter the distribution of political influence; they do not establish that every concentrated or dispersed community was deliberately targeted. Population patterns, geography and ordinary districting criteria can produce similar effects. Analysts therefore compare maps and evidence about the map-drawing process, and the standards used to assess a map depend on the law and jurisdiction involved.

The word “gerrymander” dates to Massachusetts politics in 1812. After the state legislature redrew state senate districts, a Boston Gazette cartoon published on 26 March depicted one contorted district as a salamander-like creature and labeled it the “Gerry-mander.” The name referred to Governor Elbridge Gerry, who signed the redistricting bill. The Library of Congress notes that the person who coined the term is unknown; Gerry was associated with the law, but the label does not mean he personally drew the map.

The episode gave the practice a memorable name, but strategic district drawing was not limited to Massachusetts or to the nineteenth century. The word is now used more broadly for efforts to shape representation by drawing electoral boundaries.

The legal treatment of district maps depends on what is alleged. In the United States, partisan and racial gerrymandering are distinct questions: racial discrimination in districting can be challenged under applicable constitutional and voting-rights rules, while claims about partisan advantage have followed a different legal path. In Rucho v. Common Cause (2019), the U.S. Supreme Court held that claims of excessive partisan gerrymandering present political questions beyond the reach of federal courts. The opinion did not say that every map is immune from scrutiny: it discussed roles for Congress and state-level law, and distinguished other kinds of districting claims.

States use varying rules and processes, including criteria for district boundaries, public procedures and—in some places—independent commissions. No single visual test settles whether a map is unlawful or unfair. The meaning of fairness, the permissible role of politics, and the applicable remedy remain contested questions shaped by each jurisdiction's laws and institutions.