Why do politicians gerrymander?

By J.F. | ATLANTA

IN 1812, the governor of Massachusetts enacted a measure redrawing district lines to give his party, the Democratic-Republicans (then one of America's two major political parties) an electoral advantage. One particularly oddly-shaped district resembled, to a cartoonist's eye, a salamander, pictured above. The Boston Gazette's editor combined that word with the surname of the governor, Elbridge Gerry, to produce gerrymander. Then it was a noun; today it exists mostly as a verb, though its meaning is largely the same: it refers, in an American context, to drawing legislative districts in order to maximise partisan advantage. How do politicians do it, and why?

State legislatures draw new districts every ten years (after every census). In Maryland, this year Democrats controlled the legislature, and they created a monstrosity of a district that our sister publication aptly calls the "Pinwheel of Death". Sprawling, formless and incoherent, it takes in suburbs of Baltimore, Washington and Annapolis, and much else besides. In the rugged western part of the state, Maryland's Democrats ejected a Republican by extending his district into the liberal Washington suburbs (the ousted incumbent, Roscoe Bartlett, seems to be doing okay). Republicans are at it, too: in at least seven large states, Republican representation in Congress far exceeds the party's share of the popular vote. Across the country, Democratic House candidates won 50.6% of the votes and took just 46.2% of the seats, thanks largely to cleverly drawn districts. If more anti-gerrymandering bile seems directed these days at Republicans rather than Democrats, that is because they control more legislatures. They are just doing what the other side did when it had the chance: gerrymandering, and complaining about gerrymandering, are equal-opportunity pursuits.

Some states have grown tired of the gerrymander. In Iowa, the independent Legislative Services Agency uses computer software to draw districts. The software is designed to avoid splitting counties, and to ignore all factors except population (ie, no backroom horsetrading). Here are the four beautifully clean, right-angled districts it created. In California, voters took redistricting power out of legislators' hands by ballot initiative, and created the California Citizens Redistricting Commission. The CCRC comprises 14 members: five Democrats, five Republicans and four unaffiliated or Third Party members, most of whom are drawn by lottery (any citizen can apply). ProPublica, an investigative-journalism outfit, reported afterwards that the CCRC was not as nonpartisan as many had hoped. Still, here are its districts: less clean than Iowa's but, except along the raggedy Southern California coast, no obvious Pinwheels of Death, flattened earmuffs or hyperextended crabs either.

Why do politicians do this? Because it makes their seats safer—or so they think. But gerrymandering is done to benefit parties, not individual politicians. Thus, seats grow safer only for the party: gerrymandering makes general-election challenges less likely. But as those seats become more insulated from a cross-party challenger, through gerrymandering and political self-sorting, their legislators grow increasingly beholden to just one set of increasingly strident opinions. They never have to fight for the centre, as candidates in national elections do. Those seats also grow more vulnerable to intra-party primary challengers, who will claim that the incumbent is too liberal/conservative to represent such a conservative/liberal district. During the recent federal-government shutdown, for instance, moderate House Republicans did not all toe the hawkish party line because they agreed with it. They toed it because they feared hawkish primary challengers—with good reason.