Why does it matter?
The location of district lines decide which voters vote for which representative. Changing the lines will change the relevant voters, and can change the identity, allegiance, and political priorities of a district's representative, and of the legislative delegation as a whole.
Click on the wheel to the right to see how.
American attempts to tailor district lines for political gain stretch back to the country's very origin. Patrick Henry, who opposed the new Constitution, tried to draw district lines to deny a seat in the first Congress to James Madison, the Constitution's primary author. Henry ensured that Madison's district was drawn to include counties politically opposed to Madison. The attempt failed, and Madison was elected -- but the American gerrymander had begun.
Ironically, the man who inspired the term "gerrymander" served under Madison, the practice's first American target. Just a few months before Elbridge Gerry became Madison's vice president, as the Democratic-Republican governor of Massachusetts, Gerry signed a redistricting plan that was thought to ensure his party's domination of the Massachusetts state senate. An editorial artist added wings, claws, and the head of a particularly fierce-looking salamander creature to the outline of one particularly notable district grouping towns in the northeast of the state; the beast was dubbed the "Gerry-mander" in the press, and the practice of changing the district lines to affect political power has kept the name ever since.
In most states, the gerrymander is alive and well. Politicians still carve territory into districts for political gain, usually along partisan lines. This can lead to some serious consequences for the health of the democracy:
Cherry-picking voters. Until Proposition 11 was passed in 2008, California's redistricting system was controlled by the state legislature. Under this system, after the 2000 census, the major political parties effectively decided to call a truce, and to keep the congressional incumbents of both parties safe from effective challenges. Many incumbents each paid a consultant at least $20,000 to have their districts custom-designed for safety. As one member of Congress explained: "Twenty thousand is nothing to keep your seat. I spend $2 million (campaigning) every year. If my colleagues are smart, they'll pay their $20,000, and [our consultant] will draw the district they can win in. Those who have refused to pay? God help them." In the next election, every single incumbent, Republican and Democrat, won by more than 20% . . . except for the one whose margin of victory was 19%.
Eliminating incumbents. After the 2000 elections in Virginia, the Republicans who controlled the redistricting process targeted Richard Cranwell, the Democratic leader in the state House of Delegates, who had represented his constituents for 29 years. They surgically carved his house out of the district he had represented, and placed it in the district of his 22-year colleague, Democrat Chip Woodrum. Woodrum's district looked like it had a tiny grasping hand reaching out to grab Cranwell's home. Rather than run against the hometown favorite in an unfamiliar district, Cranwell decided not to run for reelection.
Eliminating challengers. In the 2000 primary for an Illinois congressional seat, then-state Senator Barack Obama threw together a hasty campaign against a sympathetic incumbent, and won more than 30% of the vote. Though Obama lost, his campaign set the stage for a stronger showing in a potential rematch.
When Illinois redrew its districts, the state legislators deferred to incumbent members of Congress, including the incumbent whom Obama challenged. When the redistricting was done, the block around Obama's home was carved out of the district (click here for the 2000 map, and here for the 2002 map, or click on the images above). Obama would have been forced to sell his home and move in order to live in the district where he had run 2 years before.
Skewing statewide representation. In 1991, Democrats in charge of the redistricting process in Texas crammed loyal Republican voters into a district that spanned hundreds of miles, taking small slivers of land from five counties. By packing pockets of Republican voters as thoroughly as possible into just a few districts, Democrats could give themselves a better chance in the districts next door. In 1992, Republicans and Democrats each won about 49% of Texas' statewide vote . . . but under the Democratic redistricting plan, Democrats won 70% of the state's Congressional races.
Diluting minority votes. After Democrats controlled Texas redistricting in the 1990s, Republicans took charge in 2003. The redistricting battles were so fierce that Democratic legislators actually fled to Oklahoma and New Mexico in an attempt to prevent the legislature from meeting to draw lines. When the lines were ultimately drawn, they moved about 100,000 Latino voters out of one district in order to protect an incumbent who was beginning to lose the support of the Latino population. Latinos had recently become the majority of the eligible population in the district, when they were replaced by voters more likely to support the incumbent. As the Supreme Court put it, "the State took away the Latinos' opportunity because Latinos were about to exercise it."
Splitting communities. In 1992, race riots in Los Angeles took a heavy financial toll on businesses in many neighborhoods, including the area known as Koreatown. When residents of Koreatown appealed to their elected representatives for assistance with the cleanup and recovery effort, however, each of their purported representatives claimed that the area was really a part of some other official's district. The redistricting map, it appeared, had fractured Koreatown -- an area barely over one square mile -- into four City Council districts and five state Assembly districts. As a result, no legislator felt responsible to the Asian-American community.
Destroying political goodwill. In many ways, because redistricting can have such a direct impact on incumbents' electoral fortunes, it is among the most personal of issues for legislators, with every change in the lines a great favor or a piercing slight. Goodwill poisoned by the redistricting process can spill over into the entire rest of the legislative term. So it is disturbing, for example, when a federal judge quotes a Madison County, Illinois, committee chairman explaining to a colleague that "We are going to shove [the map] up your f------ a-- and you are going to like it, and I'll f--- any Republican I can."
Indeed, in Illinois, this sort of behavior seems well within the norm. In 1981, in a dispute over the handling of a redistricting plan, a legislator on the floor of the Statehouse charged the Senate President -- whereupon a legislative colleague (and former Golden Gloves boxer) punched him in the face.