Zombie Politics: Redistricting and Party Polarization

Aaron Blake:

The once-in-a-decade redistricting process has taken the nation’s already-polarized congressional map and — you guessed it! — made it even more polarized, says a new study from the nonpartisan election reform group Fair Vote

…The result is that the blue districts will, almost without fail, elect liberal Democrats, while the red districts will, almost without fail, elect conservative Republicans. And because these members basically need to please only one side of the aisle to win reelection, their incentive is to toe the party line just about 100 percent of the time.

Does redistricting makes the parties in Congress more polarized?   No.  If you want the simplest evidence, consider that polarization in the never-redistricted Senate mirrors that in the House.  If you want more sophisticated evidence, here, via Josh’s earlier post, are political scientists Nolan McCarty, Keith Poole and Howard Rosenthal (gated, earlier ungated version):


Both pundits and scholars have blamed increasing levels of partisan conflict and polarization in Congress on the effects of partisan gerrymandering. We assess whether there is a strong causal relationship between congressional districting and polarization. We find very little evidence for such a link. First, we show that congressional polarization is primarily a function of the differences in how Democrats and Republicans represent the same districts rather than a function of which districts each party represents or the distribution of constituency preferences. Second, we conduct simulations to gauge the level of polarization under various “neutral” districting procedures. We find that the actual levels of polarization are not much higher than those produced by the simulations. We do find that gerrymandering has increased the Republican seat share in the House; however, this increase is not an important source of polarization.

Die, zombie, die!

(Earlier posts in this series are here.)

15 Responses to Zombie Politics: Redistricting and Party Polarization

  1. Michael October 21, 2012 at 4:22 pm #

    What? No Drezner citation?

  2. Phillip October 21, 2012 at 6:04 pm #

    Didn’t Theriault also address this question to the same finding in “Party Polarization”?

    • John Sides October 21, 2012 at 7:44 pm #

      Phillip: He did and, if my memory is correct, arrived at a similar finding.

  3. dlw October 21, 2012 at 6:22 pm #

    It’s the exclusive use of winner-take-all elections that makes gerrymandering “work” that is the true villain, but more people understand why gerrymandering is “bad” than why first-past-the-post is bad.

    As such, I attribute FairVote’s approach to be more marketing driven than analysis-driven….

    Let’s kill the bigger bad and the smaller bad in one blow by giving state’s the right to use American forms of Proportional Representation, chosen by state-level refendum, and then pushing for its implementation in nat’l and state congressional elections!

  4. dlw October 21, 2012 at 8:00 pm #

    My hypothesis is that when an electoral system nearly exclusively uses single-winner first-past-the-post, or multi-winner at-large elections, that the system tends to tilt to effective single-party domination as used to be the case in Egypt and Mexico.

    These same rules also make gerrymandering “work” to stifle democracy. It’s a lot harder to gerry-mander a legislative system that consists of Irish-style 3-5 seat Proportional Representation elections.

    So ideally, they’d be focused on that, but folks don’t geet that and they do get gerrymandering and since the two tend to be correlated the smart marketing pitch is to focus on gerrymandering.


    • Ali October 22, 2012 at 11:13 am #

      What about in the UK or France?

  5. dlw October 22, 2012 at 2:56 pm #

    What about them?


  6. likmai bawlsplz October 23, 2012 at 9:38 am #

    From the paper:

    “We do find that gerrymandering has increased the Republican seat share in the House;
    this increase is not an important source of polarization.”

    “Nothing we say should be interpreted as contentment with congressional
    districting as it is currently practiced. The protracted political and legal battles over the
    boundaries cannot help but diminish the legitimacy of American democracy. And
    redistricting does appear to have a negative impact on electoral competition. There are
    many reasons to do something about gerrymandering. But reducing polarization is not
    one of them.”

    Your blog misrepresents the findings and conclusions of this paper in egregious fashion.

    • John Sides October 23, 2012 at 9:49 am #

      Likmai: I cannot see how you could possibly claim that. The post argues that redistricting does not increase polarization — despite the “zombie” myth that it does. That is precisely what the paper argues, including in the passages you cite!

      • likmai bawlsplz October 23, 2012 at 2:55 pm #

        Yet right here they admit to finding polarization:

        “This upper bound is very small and realistically can account, at most, for 10-15% of the increase in polarization since the 1970s. “

        What’s problematic is that they’re not hunting down other potential sources of polarization (barring sorting) so it’s not possible to evaluate how significant it is relative to the elements that make up the other 90-85% of the issue. It could be utterly irrelevant or dependent on another factor in a more complete formula. It could also be the biggest fish in a pool of very tiny factors. But in this model it is most definitely relevant, if small:

        “That is, even though the gerrymandering effect estimated using a simple geographic constraint is much smaller than the effect based only on purely random assignment within each state, the effect remains statistically significant. “

        They do however absolutely find that there is an effect and that it is statistically significant. Your blog post is therefore incorrect and a misrepresentation of the paper.

        • John Sides October 23, 2012 at 8:28 pm #

          That’s extremely selective quotation. The passage following the first quotation you cite:

          “Because we use county-level data, this bound is almost
          certainly biased upward. But most damning, this upper
          bound does not increase substantially following redistricting
          as the gerrymandering hypothesis would suggest.”

          Moreover, the statistically significant effect — that of imposing compactness and contiguity via latitude — you cite is quite small. And then in the conclusion, they are clear how they view the thrust of their results, which is to downplay the role of redistricting in furthering polarization to an extent far greater than commentators suggest. To cite the very same passage you originally cited (seemingly unaware that it contradicts your argument):

          “There are many reasons to do something about gerrymandering. But reducing
          polarization is not one of them.”

          Finally, if you continue to post comments under crude pseudonyms, I will delete those comments.

          • likmai bawlsplz October 25, 2012 at 10:01 am #

            Oh lawks, you mean I’ll be deleted from a blog’s comment page?! Heavens no!

  7. Chris October 24, 2012 at 1:32 am #

    The link you provided on political polarization between the house and senate seems to show a pretty large split between the house and the senate in terms of polarization, with the house becoming more polarized. You said the complete opposite, but the first graph on the page you linked to shows a sharp increase after 1994 in the house and continuing.

    Its obviously not all of it, but it seems to have an effect.

    Also, you say “Die Zombie Die!” but you did a pretty horrendous job of making a clear and concise argument against this misconception. You patronizingly listed off several ‘links’ that would prove your point, but the links are just their personal blog and your entire post is basically revolved around this one paper. I just read it and wasn’t really blown away with anything in it. It basically says gerrymandering causes polarization in some cases, but there are all these times where on the whole it has no effect.

    Just calm down. Political Science hasn’t solved everything…

    • John Sides October 24, 2012 at 8:40 pm #

      Chris: Look carefully at the graph. From the low point of polarization in the mid-20th century, polarization in the Senate has increase from 0.3 to 0.85, a difference of 0.65. And in the House it has increased from 0.45 to 1.1, a difference of…0.65! So it is not greater in the House.

      I wish I could respond to the rest of your comment, but your own summary of the article is so vague that I don’t know where to respond. What are “in some cases”? And why is “all these times where on the whole it has no effect” any different than the message of my “horrendous” and “patronizing” post?

      Moreover, this is not the only study that reaches a similar conclusion. See the book by Sean Theriault cited up-thread.