Gerrymander, apportionment of electoral districts in such a way as to give the political party in power an advantage in electing its representatives. Gerrymandering can be accomplished by dispersing an opponent’s supporters across so many electoral districts that they will be in the minority everywhere or, alternatively, concentrating them into a small number of districts to minimize their electoral impact. Gerrymandering sometimes results in electoral districts of curious shapes.

The term gerrymander originated in 1812, when Governor Elbridge Gerry of Massachusetts signed a bill giving his own Democratic-Republican Party, which had temporarily come into power, an advantage over the Federalists. One electoral district was shaped so fantastically that it was compared by one Federalist to a salamander. “No,” said another, “better call it a Gerrymander.”

The first known instance of gerrymandering in the United States took place in 1709, when various counties in Pennsylvania tried to deprive Philadelphia of due representation. Later examples were a “shoestring” district in Mississippi, about 480 km (about 300 mi) long and 32 km (20 mi) wide, and a district in Pennsylvania shaped like a dumbbell. In 1842 Congress passed the Reapportionment Act, requiring that electoral districts for members of the House of Representatives be compact and contiguous.

Even when observing the letter of the law, however, gerrymandering is still possible. Among the remedies that have been proposed for gerrymandering are the election of all representatives at large and election by the system of proportional representation. In the 1962 case Baker v. Carr, the Supreme Court of the United States, in the first of a series of decisions about election practices, ruled that election districts in all states be apportioned according to the principle of “one man, one vote.” These decisions placed some limits on opportunities for the most blatant forms of gerrymandering.

Beginning in the 1980s, the Court ruled that legislative district boundaries could not be drawn in ways designed to deprive minority voters of political influence. Congress sought to take this point one step further when, in 1982, it amended the Voting Rights Act of 1965 to encourage the creation of legislative districts likely to be represented by African American or Hispanic legislators. This enactment, however, led to lawsuits by white voters, who claimed that they were now the victims of racial gerrymandering. Beginning with the 1993 case of Shaw v. Reno, the Supreme Court has ruled that race may be taken into account but may not become the predominant factor influencing the drawing of district boundaries.

The Supreme Court has also examined the issue of partisan gerrymanders undertaken entirely to give one political party an advantage in elections. In 1986 the Court ruled that such manipulation could be unconstitutional in some cases, but could not agree on a standard for determining excessively partisan redistricting. In the 2004 case of Veith v. Jubelirer, the Court, by a 5 to 4 vote, upheld a Pennsylvania districting plan designed expressly to increase the number of legislative districts likely to be won by Republicans. So long as district boundaries were not discriminatory on the basis of race or in violation of the “one person, one vote” norm, the Court ruled, the fact that they gave an advantage to Republicans did not warrant judicial intervention. However, the Court left open the possibility of ruling on future political gerrymandering claims under a precisely defined standard.