Gerrymandering

Tuesday we went to see the movie Gerrymandering, a documentary about the practice of redrawing legislative districts for political advantage. Admittedly the factor that got us to the showing was that Pica’s cousin Susan did the sound production on the movie, but the topic is a good problem in geography. The film focused on the passage of Proposition 11 two years ago in California, an voter initiative to transfer the power of redrawing districts from the legislators themselves to an independent commission. This proposition narrowly passed, and in the finest manner of the carnival that is California initiative politics, there are dueling propositions on the upcoming November ballot to repeal it (Proposition 27) or expand its powers (Proposition 20). The movie was tautly edited, with many animated sketches of the cartographic absurd districts all over the country produced by gerrymandering.

That legislative districts should be at least somewhat cartographically compact is a principle acknowledged by the courts, though rarely seen in practice. I wonder though if there are any sort of “natural” boundaries that can be used to constrain how one draws legislative districts, the problem being that there are an infinite number of ways one can draw lines on a map. After pondering this for a bit I came up with counties, the one set of political boundaries below the scale of individual states that is fairly stable over the years. Of course county boundaries rarely align with population density, and to ensure equal representation some counties would have to be lumped into multicounty districts. By contrast, highly populated counties (for instance Los Angeles County in California) would not be geographically split into separate districts; rather voters would elect several representatives at once from this “superdistrict”. The film interviewed legal scholar Lani Gunier, who it turns out has had ideas along these lines, but the film didn’t go into such alternative ideas. Maybe they fell in interview bits that were left on the cutting room floor.