Tag Archives: gerrymandering

Rebecca Dallet and the gerrymandered Assembly map

The fate of the current Wisconsin Assembly district map, precision-engineered to maintain a Republican majority in the face of anything short of a major Democratic wave election, is in the hands of the Supreme Court, which could announce a decision in Gill v. Whitford any day.

One theory of gerrymandering is that the practice isn’t much of a problem, because the power of a gerrymandered map “decays” with time — a map that suits a party in 2010 may, due to shifting demographics, be reasonably fair a few years later.

How’s the Wisconsin gerrymander doing in 2018?  We just had a statewide election in which Rebecca Dallet, the more liberal candidate, beat her conservative rival by 12 points, an unusually large margin for a Wisconsin statewide race.

The invaluable J. Miles Coleman broke the race down by Assembly district:

Dallet won in 58% of seats while getting 56% of the vote.  That sounds fair, but in fact a candidate who wins by 12 points is typically going to win in more seats than that.  (That’s why the courts are right to say proportional representation isn’t a reasonable expectation!)

Here’s the breakdown by Assembly district, shown a little bigger:

Dallet won by 2 points or less in 8 of the Assembly districts.  So, as a rough estimate, if she’d gotten 2% of the vote less, and won 54-46 instead of 56-44, you might guess she’d have won 49 out of 99 seats.  That’s consistent with the analysis of Herschlag, Ravier, and Mattingly conducted last year, which estimates that under current maps Democrats would need an 8-12 point statewide lead in order to win half the Assembly seats. (Figure 5 in the linked paper.)

I don’t think the gerrymander is decaying very much.  I think it’s robust enough to make GOP legislative control very likely through 2020, at which point it can be updated to last another ten years, and so on and so on.  This isn’t the same kind of softcore gerrymandering the Supreme Court allowed to stand in 1986, and I hope the 2018 Supreme Court decides to do something about it.

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Are Alabama’s House seats gerrymandered?

This map has a lot of people saying so:

 

Here’s what I think:  Alabama’s House maps might well be gerrymandered, but the Moore-Jones numbers aren’t very strong evidence.

First of all, about that weirdly shaped District 7 where so many Democrats live.  That’s a majority-minority district.  The Voting Rights Act requires the creation of some such districts, and that provision has increased the representation of racial minorities in Congress.  But most people agree they hurt Democrats overall.  You might be able to draw a district map for Alabama, Republican though it is, with two districts where Democrats have a chance instead of one.  But you’d also increase the likelihood of Alabama sending an all-white delegation.

Alabama, without District 7, is about 78% white, and white people in Alabama are about 85% Republican.  It’s not gerrymandering that Dems don’t have a chance in those six districts under normal conditions; it would happen just about any way you drew the maps.

But the Moore-Jones election was anything but normal conditions!  Did the party draw a map designed to withstand a historic Democratic turnout wave?

I doubt it.  Suppose you wanted to draw a map that would keep your big House majority even if just over half of Alabamian voters chose the Democrat.  You’ve got no chance in AL-7, and in the other 6 districts combined, the Republican is winning by 10 points.  Well, the last thing you’d do is draw an ultra-Republican district like AL-4; that makes the other districts way too close.  You’d take some of those wards and move them over to shore up AL-5, which Moore won by less than half a percent.  You might also try to concentrate the more Democratic parts of AL-1 and AL-2 into one, creating a district you might lose in a wave but leaving the rest of the state so solidly Republican that even an election more disastrous than this one for Republicans would leave five seats in GOP hands.

Outside district 7, Alabama is a very Republican state, even when offered the weakest Republican candidate in recent memory.  That’s the simplest explanation for why Moore finished ahead in districts 1-6, and it’s the one I favor.

Update:  Some people have communicated to me that in their view district 7 is more majority-minority than the Voting Rights Act requires, and that the district was drawn this way on purpose in order to increase Republican margin in the other 6 districts.

 

 

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“Worst of the worst maps”: a factual mistake in Gill v. Whitford

The oral arguments in Gill v. Whitford, the Wisconsin gerrymandering case, are now a month behind us.  But there’s a factual error in the state’s case, and I don’t want to let it be forgotten.  Thanks to Mira Bernstein for pointing this issue out to me.

Misha Tseytlin, Wisconsin’s solicitor general, was one of two lawyers arguing that the state’s Republican-drawn legislative boundaries should be allowed to stand.  Tseytlin argued that the metrics that flagged Wisconsin’s maps as drastically skewed in the GOP’s favor were unreliable:

And I think the easiest way to see this is to take a look at a chart that plaintiff’s own expert created, and that’s available on Supplemental Appendix 235. This is plain — plaintiff’s expert studied maps from 30 years, and he identified the 17 worst of the worst maps. What is so striking about that list of 17 is that 10 were neutral draws.  There were court-drawn maps, commission-drawn maps, bipartisan drawn maps, including the immediately prior Wisconsin drawn map.

That’s a strong claim, which jumped out at me when I read the transcripts–10 of the 17 very worst maps, according to the metrics, were drawn by neutral parties!  That really makes it sound like whatever those metrics are measuring, it’s not partisan gerrymandering.

But the claim isn’t true.

(To be clear, I believe Tseytlin made a mistake here, not a deliberate misrepresentation.)

The table he’s referring to is on p.55 of this paper by Simon Jackman, described as follows:

Of these, 17 plans are utterly unambiguous with respect to the sign of the efficiency gap estimates recorded over the life of the plan:

Let me unpack what Jackman’s saying here.  These are the 17 maps where we can be sure the efficiency gap favored the same party, three elections in a row.  You might ask: why wouldn’t we be sure about which side the map favors?  Isn’t the efficiency gap something we can compute precisely?  Not exactly.  The basic efficiency gap formula assumes both parties are running candidates in every district.  If there’s an uncontested race, you have to make your best estimate for what the candidate’s vote shares would have been if there had been candidates of both parties.  So you have an estimate for the efficiency gap, but also some uncertainty.  The more uncontested races, the more uncertain you are about the efficiency gap.

So the maps on this list aren’t the 17 “worst of the worst maps.”  They’re not the ones with the highest efficiency gaps, not the ones most badly gerrymandered by any measure.  They’re the ones in states with so few uncontested races that we can be essentially certain the efficiency gap favored the same party three years running.

Tseytlin’s argument is supposed to make you think that big efficiency gaps are as likely to come from neutral maps as partisan ones.  But that’s not true.  Maps drawn by Democratic legislatures have average efficiency gap favoring Democrats; those by GOP on average favor the GOP; neutral maps are in between, and have smaller efficiency gaps overall.

That’s from p.35 of another Jackman paper.  Note the big change after 2010.  It wasn’t always the case that partisan legislators automatically thumbed the scales strongly in their favor when drawing the maps.  But these days, it kind of is.  Is that because partisanship is worse now?  Or because cheaper, faster computation makes it easier for one-party legislatures to do what they always would have done, if they could?  I can’t say for sure.

Efficiency gap isn’t a perfect measure, and neither side in this case is arguing it should be the single or final arbiter of unconstitutional gerrymandering.  But the idea that efficiency gap flags neutral maps as often as partisan maps is just wrong, and it shouldn’t have been part of the state’s argument before the court.

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