Redistricting

Redistricting is the process of drawing electoral district boundaries for the purpose of electing members to a legislative body. Redistricting is conducted periodically for legislative bodies in countries that elect candidates to office from discrete geographic districts (e.g., Canada, United Kingdom, United States). In the United States, since the 1840s (with rare exceptions), members of the U.S. House of Representatives have been elected from discrete single-member districts. In addition, many members of U.S. legislative bodies at other scales (state, county, and local legislatures) are elected from geographically based districts (whether they be single- or multimember). In the United States, electoral districts generally are redrawn once a decade following the release of the decennial census population data so as to reflect population changes uncovered by the census. In most cases, state legislatures are responsible for redistricting U.S. House and state legislative seats. In some states, however, nonpartisan agencies (e.g., Iowa) or bipartisan commissions (e.g., New Jersey) are given the power to redistrict. Such efforts aim to reduce the scope of partisanship and gerrymandering (the intentional drawing of election district boundaries to the advantage of one group at the expense of another) in the redistricting process.

Since the 1960s, redistricters in the United States have been constrained by federal court decisions in how districts are to be drawn. Starting in the 1960s and continuing to the 1980s, a series of U.S. Supreme Court decisions mandated that U.S. House districts within a state be equal in population and that state legislative districts be nearly equal. The court rulings were aimed at dealing with issues of malapportionment (large differences in the populations of election districts within the same political jurisdiction) that had kept rural interests in control of many state legislatures and had given them disproportionate power in the U.S. House during the early and mid-20th century as the population shifted from rural to urban areas.

During the early 1990s, redistricters greatly increased the number of African American and Latino population–majority congressional and state legislative districts under guidance from the U.S. Department of Justice in its interpretation of amendments to the Voting Rights Act of 1965. Such affirmative districting measures led to large increases in the number of African American and Latino legislators elected. However, in so doing, some of these new minority–majority districts were geographically extensive and cut across well-recognized regional boundaries. During the mid- and late 1990s, federal courts called into question such minority–majority districts with[Page 405] lesser levels of geographic compactness if they were drawn based primarily on racial factors.

During the 2000s, with partisan control of the U.S. House closely contested and determined by a small margin of seats, the incidence of partisan gerrymandering increased as majority party leaders in state legislatures created plans that helped to increase (or at least maintain) their party's share of seats in the U.S. House (e.g., Texas). Although partisan redistricting has occurred since the beginning of political parties in the United States (and has not been declared unconstitutional by the U.S. Supreme Court), such gerrymandering has become easier during recent decades due to advancements in geographic information systems (GIS) technologies that allow district mapmakers to create and analyze a greater multitude of redistricting plans on their computers at much greater speeds than they could previously. At the same time, public interest groups have also invested in GIS technologies to highlight and call into question the partisan nature of such district plans.

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