Thursday, January 11, 2018

A Solution to Gerrymandering

 

Ask virtually anyone their opinion of 'gerrymandering' and you are virtually certain to get a negative response.  Gerrymandering, the practice of drawing political districts in order to make them predictably safe for one party or the other (only Republicans and Democrats get to draw district boundaries because no other parties ever have sufficient clout to draw district boundaries because they have been gerrymandered into obscurity) has been practiced since the early 19th century when political parties began to form, and has always been looked down upon — officially — by the general populace.  The result of gerrymandering is often a district whose boundaries appear to be more random than regular, sometimes including stretches that contain no actual voters.  It has always been seen as something of a political dirty trick, herding your opponent's voters into the corner while spreading your own voters strategically so as to win more districts, win more positions in the government, and win more power to install your policies.  I say 'officially' because few people complain that gerrymandering has given them more power than they deserve.

Nevertheless, principled people have long sought a way to prevent any party drawing district boundaries for nefarious purposes.  In 200 years, their efforts have been largely fruitless because any law that would effectively prevent gerymandering would, it was thought, be large, complicated, and difficult to administer if it could actually be passed by a legislature, something not at all certain.

That, at any rate, is the conventional wisdom.

I think I may have stumbled upon a solution, a rule that is simple, straight-forward, easy to understand, and (most importantly) easy to police.  It is a two-part rule:

  1. it must be legally possible for any person to walk from any place within a district to any other place within the same district without leaving the district;

  2. the distance from any point within the district to its center may not be more than 2.5 times the distance to the nearest district center not within the district.

Provision (a) prevents connecting two or more sections by routing it (e.g.) along an interstate highway or private rights-of-way because it's illegal to walk on them.  Provision (b) tends to make each voting district more circular than extended, 'extended' being the sign of a manufactured district.

'2.5' is arbitrary.  The closer you move it toward 1, the more circular the district would become.  Total circularity is obviously impossible; 2.5 seems a reasonable compromise, but if you think it should be 3.64, I can completely understand that; you couldn't convince me that 17 is equally reasonable.

What's left is a district that has no long, spindly alleys connecting two pieces of the same district, and that is compact enough such that, from wherever I am in that district, if the district center is five miles away, there isn't another district center closer than two miles.  I think that no one would complain (aloud, in public) were every district constructed to these specifications.

What am I missing?

 

1 comment:

  1. I've thought about a simpler approach along these lines: set a maximum ratio of district perimeter to the square root of its area. The flaw in both solutions is the same: it's possible to use computer optimization to create districts that are geometrically regular but nevertheless give one party a big advantage. Setting a limit on efficiency gap, or the difference between the parties' ratios of seats won to total votes on the new map (based on local results in the prior election), is a better approach in that it is directed at the core issue.

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