Redistricting: A Geek Proposal

One of the peculiarities of the U.S. political system is that it is possible in principle for one party to win a majority of both houses of Congress and the presidential election with slightly over 25% of the votes—properly distributed. 50% +1 of the votes in 50%+1 of the congressional districts elect a majority of the house, 50%+1 in the twenty-six smallest population states elect a majority of the senate, although it may take multiple elections, and similarly, with more states, for winning the electoral college.

That uneven a distribution is unlikely to happen by chance—but it is not always necessary to leave it to chance. Back in 1812 Elbridge Gerry, governor of Massachusetts, signed a bill redrawing state senatorial districts in a way that favored his (Democratic-Republican) party. One of the districts looked rather like a dragon, leading critics to dub it a "gerrymander." The term survives, mostly as a verb describing the practice of redrawing electoral districts to favor those who redraw them. It can be used by one party to try to increase the number of its candidates who are elected by concentrating as many as possible of the opposition voters in as few districts as possible and (a somewhat riskier strategy) creating as many districts as possible where their voters are a majority, but not a large majority. It can be done on a bipartisan basis to guarantee incumbents of both parties safe seats by concentrating voters of one party in some districts, of the other in others. California recently redrew districts, using an at least nominally non-partisan group to do it; when I voted this morning, there was a proposition on the ballot to cancel the result. Which reminded me of an old idea of mine for solving the problem.

A state gives some body—the legislature, the Supreme Court, a non-partisan group—the authority to decide among redistricting proposals. There is, however, one restriction. Every proposal must take the form not of a map but of a computer program. Inputs include potentially relevant criteria such as town and county boundaries, but may not include any information on past voting or proxies for voting such racial, educational, or professional characteristics of the population. There is an upper limit to how big the program may be.

That restriction will not prevent people from trying to create programs whose output favors their side, or the body choosing from favoring ones that they think favor theirs. It will, however, sharply restrict their ability to do so, since the information needed to do it well will not be available to the program. They can try various versions, look at the results, and choose the one they like best, but that is all they can do.