For the true hardcore…A version of the MATLAB code I used is now available. I used gerry.m for Part 1, and delegations.m for Part 2. Voting dat...
Gerrymandering makes for interesting mail! Here are some excerpts from activists, a journalist, political scientist, and a few redistricters.
Journalist Paul H.Rosenberg writes:
I still don’t grasp how your methodology is supposed to identify non-geographic partisan gerrymandering as a distinct phenomenon. If it did, that would be super. But I just don’t follow…..it doesn’t bother me — at this stage, anyway — to ignore other concerns, such as minority representation. I just want to understand the logic dividing geographic impacts on redisctricting from all the rest. Lumping all the rest under “potentially partisan” makes perfect sense to me.
Here’s my take. The general idea is that the US is diverse in many ways: population density, partisan preference, and ethnicity/interest groups. Given that diversity, we can get a sense for what these factors could do to the partisan makeup of a Congressional delegation, by sampling districts around the country to see how they would add up to State X’s vote totals.
My approach is built on the idea that one can account for the general relationship between all this diversity and seat counts. It includes all the factors above. What is left is factors that are peculiar to a state. Since all large states have cities within them, that is not a factor that can account for a particular state’s outcome being different.
Probably the right way to resolve this is to do the same calculation using 2002-2010 House election results. I will do that in the near future using the same approach. If there’s a big jump in the index I have designed from 2010 to 2012, that would indicate that something happened in 2011. Which brings us back to redistricting.
Paul also suggested separating states into three tiers of urbanization. That would certainly address the urbanization-traps-Democrats idea. I have found a certain lack of clarity as to the relative size of these effects. My current guess is that gerrymandering’s overall effect is about 2-3 times as large as that of urbanization. But that’s strictly a gut feeling.
Several people described some close-up views of redistricting. Brent Benson, who writes the blog Mass. Numbers, reports:
I had a first-hand look at the redistricting process in Massachusetts as my wife participated in the process as a State Representative. In my opinion, the Democratic supermajority in the Massachusetts state legislature bent over backwards to not gerrymander, going along with your proposition that U.S. gerrymandering is not symmetrical. I actually didn’t see much emphasis on incumbent protection in MA at the Congressional level, to the point that Barney Frank retired rather than face running in a district in which he didn’t feel comfortable and John Tierney came within a a few votes of losing his seat. That being said, all of the Congressional Dems won in MA.
Before anyone makes light of that last sentence…in six races where Massachusetts candidates had opponents, the vote share was 66% D, 34% R (and across all districts, it was 75% D, 25% R). Based on these numbers, a 9-0 split is well within expectations.
S.A. gave a view from Ohio:
Here in Ohio, they tried to institute an “anti-gerrymandering” issue using a citizen’s commission to replace the legislature-drawn districts. It failed miserably because it was unfunded and it was confusing.
As a numbers guy, I thought, “why not solve the gerrymandering problem numerically?” In other words, make some simple, numerical rules, easy-to-measure, easy enough to program, and let the legislature do its gerrymander thing with tight handcuffs on? No “split-line” confusion or anything, use existing precincts, etc.
Illinois State Representative Mike Fortner writes:
As a member of the minority in Illinois, I didn’t have much impact on the map here, but I am an avid supporter of redistricting reform and competed in and won the 2011 Ohio Redistricting Competition. Even though I am a Republican, the Democrats in Ohio used one of my entries as their proposal for Ohio congressional districts.
Since then, I have been developing a neutral redistricting model based on graph theory. It is based on geographic criteria, but some have claimed that any purely geographic model would be inherently biased in favor of Republicans. This is where your article peaked my interest, since it implies that any geographic bias is small compared to the effects of partisan gerrymandering. Your statistical model would seem to be one way to more thoroughly test that hypothesis.
I have started to apply my model to some of the states, but would like to confirm that it is sufficiently neutral. If you (or a colleague) are interested in testing the contention that there are sufficiently neutral criteria for creating districts, then I would offer a collaborative effort by supplying plans to test.
I heard from political scientists as well. Eric McGhee from PPIC and The Monkey Cage had useful comments, focusing in part on incumbency. An excerpt:
First, I think your analysis is more similar to Nicholas Goedert’s Monkey Cage post than you might think…both you and Nick get a total redistricting effect of about 12 seats for Republicans under a counterfactual where every state uses an independent commission. Second, I don’t think you can add this first effect to the 6 or 7 seats that you and I found for the 2011 redistricting. The 2011 effect is (presumably) due to increased Republican control….
[Finally], I hate to climb on my old hobbyhorse, but none of this analysis incorporates incumbency. It’s easy to discount the incumbency advantage because party is so important these days (indeed, the district presidential vote is a much, much better predictor than it used to be). Nonetheless, independent of district partisanship, there’s about a 10 point difference between a seat with a Democratic incumbent and one with a Republican incumbent….
One final thought: I’ve never argued that partisan gerrymanders don’t exist. Certainly, parties often *try* to gerrymander. Instead, I’ve argued (based on a lot of good poli sci evidence) that the intended results often don’t materialize, that there are many constraints that frustrate a party’s attempts at rigging the lines in the first place, that incumbency is often a big part of the story and further complicates efforts at lasting effects, and that any sort of national impact is usually difficult to find.
The first two points are good. Incumbency…this is connected to the question of building competitive districts, which is a priority for many redistricters.
But “Many constraints that frustrate a party’s attempts” to gerrymander? The evidence I’ve been laying out plainly contradicts this. Looking at Pennsylvania, North Carolina, Ohio, and Michigan, where a 50.6D-49.4R %vote split led to a 43R-18D seat split, clever people can find a way around those constraints.
Rob Richie from FairVote wants to find a way to toss the whole system nationally.
[Regarding nonpartisan redistricting commissions], progress has been slow and erratic – with the latest example being a massive rejection of reform in a statewide ballot measure in Ohio last year and a landslide vote to uphold Maryland’s gerrymandered congressional map. It’s hard to build a reform movement around independent redistricting…the message really is that one set of elites can do a better job structuring your representation than another group of elites….
So then the question becomes what might happen that could get us to a point where a national law could be imposed? What has a better chance of mobilizing people to fight for it — to have a coalition of key constituency groups that get something directly out of it? Although obviously a heavy lift, I think a statute to do fair voting has a much better chance of doing that, as it really empowers both individual voters and constituency groups in a way that is quite different than any single member district process. And it sure gets you to a whole different place if you win it.
Finally, I thank Corey Kane (soon to be Washington correspondent for the Houston Chronicle) for conversations on this subject some time back. He has a recent piece on gerrymandering here.