I’ve got a new piece at the Institute for Humane Studies' Learn Liberty explaining the basics of how politicians rig district lines to reward friends and punish foes, the entrenchment of an established political class that results, and how it might be combated. Snippet:
In a classic single-party gerrymander, the party in power packs opposition voters densely into as few districts as possible, thus enabling its own voters to lead by a comfortable margin in a maximum of districts. When a legislature is under split party control, the theme is often bipartisan connivance: you protect your incumbents and we’ll protect ours. Third-party and independent voters, as is so common in our system, have no one looking out for their interests....
Geographic information systems (GIS) methods now allow members of the public using inexpensive software to analyze the full data set behind a map. In several states, that has meant members of the public could offer maps of their own or make well-informed critiques of legislators’ proposed maps. In one triumph for citizen data use, the Pennsylvania Supreme Court invalidated a map drawn by lawmakers as clearly inferior to a map that had been submitted independently by an Allentown piano teacher.
Separately, I generally agree with what Aaron Blake writes in a new Washington Post piece: with so many other solid reasons to end gerrymandering, there’s no need to over-sell two arguments frequently invoked against it, the polarization thesis and the “GOP-fixed House” thesis.
On the much-noted trend in national politics toward ideological polarization, it seems clear that gerrymandering is but one contributing factor among many. The U.S. Senate, for which districting is not an issue, has followed a path not too far from that of the House, with virtually all Senate Democrats now to the left of virtually all Senate Republicans and stepped-up party-line cohesion on voting. And states with relatively fair districting maps have experienced polarization with the rest. So, yes, reform will probably make a difference at the margins for those who would like there to be more swing or contestable seats, but don’t expect miracles.
And while gerrymandering today on net benefits Republicans (which has not always been the case), it is probable for reasons Blake explains that fair/neutral districting would still have produced a GOP-run House in 2016. An important reason is that Democratic voters are so concentrated in cities.
For some of the many other reasons the cause is worth pursuing no matter which party (if any) you identify with, check out my IHS piece or, for somewhat more detail, my chapter on the subject in the new Eighth Edition of the Cato Handbook for Policymakers. I've previously written several pieces about my experience dealing with the problem in my own state of Maryland.