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One last gerrymandering case…Abbott v. Perez in Texas

April 23rd, 2018, 11:16am by Sam Wang

This week, the Supreme Court hears one last case on gerrymandering for the term. This one’s a racial-gerrymandering case, Abbott v. Perez. The history of the case is long and tortured – see Ian Millhiser’s summary. Also, here’s great coverage from Alexa Ura at the Texas Tribune.

This case is in a separate category than the partisan-gerrymandering cases (Whitford, Benisek, and Rucho), where there is an opportunity to create new guardrails. Instead, Abbott seems more a case study in how a dispute can be slow-walked – in this case since 2011. I agree with Millhiser that the slow-walking is upsetting. But it could arise from caution in the face of complexity (or in the partisan cases, the absence of settled doctrine). So one could justify that aspect of how gerrymandering cases are handled.

Millhiser is quite negative about the Court’s approach to gerrymandering. At the risk of sounding Pollyanna-ish, let me take a more positive view of where the Court may head in the future. Indeed, I see potential for substantial improvement, by expanding gerrymandering from race into the domain of party. [Read more →]

→ 7 CommentsTags: Redistricting

At the Harvard Law Review Blog

April 11th, 2018, 8:19pm by Sam Wang

At the Harvard Law Review Blog, I lay out a framework for organizing the many tests for partisan gerrymandering. The framework may be useful for establishing a logical and manageable standard to define the offense. Read “An Antidote To Gobbledygook“!

P.S. Monday April 17th: The piece is linked from SCOTUSBlog!

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An Antidote for Gobbledygook: Organizing The Judge’s Partisan-Gerrymandering Toolkit

April 7th, 2018, 3:04am by Sam Wang

The Supreme Court appears to be at loggerheads in its search for a single standard for partisan gerrymandering. Here, Sam Wang and Brian Remlinger collect the many statistical standards into a single toolkit. Basically, all the tests fit into two categories: inequality of opportunity and durable outcomes. Read our working draft, which we have uploaded as an SSRN preprint here.

Here’s the law side of our argument, in a nutshell:

We propose that mathematical tests fall into two categories: tests of unequal opportunity and tests of durable outcome. These tests draw upon ideas borrowed from racial discrimination law, while extending that doctrine in directions that are unique to the category of partisanship.

Opportunity is easily defined and corresponds to a core principle of democracy: it should be possible to vote out a candidate or incumbent. While it is true that voters have clustered into enclaves that sometimes make an incumbent or party safe, it is equally the case that redistricters can manipulate lines to amplify the effects of that natural clustering. Just as members of a racial group can have the representational rights impaired through gerrymandering, so it is with partisans.

Test of unequal opportunity are easily conceptualized as an extension of racial discrimination. Where partisans comprise a small fraction of the population, the appropriate procedure is to examine individual districts. Where partisans comprise close to half the voters of a state, a statewide evaluation is necessary.

However, party is a more mutable characteristic than race. Therefore one may ask whether a partisan advantage is durable.  Our second standard, testing for inequality of outcome, addresses this problem by probing whether a particular arrangement is likely to be robust to likely changes within a redistricting cycle. This can be gauged not just by waiting for multiple elections to pass (which would vitiate the remedy) but by gauging the partisan effects of a map by examining likely outcomes under a variety of conditions. This is well within the reach of modern expert witnesses.

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Today’s big partisan gerrymandering case: Maryland (Benisek v. Lamone)

March 28th, 2018, 11:40am by Sam Wang

So, oral arguments in Benisek just ended. Here’s the transcript! A round-up of the case is at SCOTUSblog. . Audio will soon be available here.

Bloomberg reports that multiple justices questioned whether a First Amendment-based approach of looking at single districts (as is done for racial gerrymandering) is the right approach to regulate the Maryland gerrymander. To remind everyone…it is possible to analyze Maryland on a statewide basis to identify a statistical anomaly. See my Election Law Journal analysis here. Rick Hasen posts a pessimistic take here. He thinks there’s no consensus about how to define a partisan gerrymander, and he thinks this is a problem.

However, here at the Princeton Gerrymandering Project we see a way forward. As PGP’s Will Adler points out, in both Whitford and Benisek oral arguments, Justice Kennedy asked the same question: whether it would be permissible for a state law to mandate that partisanship be a “predominant consideration.” This seems to be a starting point. After that, sure, there’s a question of how to set a standard. In my view it would involve establishing the idea that a map is extreme. As we’ve written before, significance testing provides a path forward: t-test, mean-median difference, Monte Carlo, and map-drawing. They’re all related ideas, and they comprise a valuable toolbox for the judge.

PGP’s own Brian Remlinger was in the room for oral argument. He reports:

That was something. The liberals tore into the Republican plaintiff for not having a clear test, but Roberts tore into the Democrats for discriminating against the Republican voters, so his vote may be in play. He seems interested in doing something. Overall, I am more optimistic that it’s not game over when Kennedy retires.

I think whatever the Court does will include clear guidance on how to distinguish an unacceptable gerrymander from normal redistricting. Whitford wasn’t mentioned too much, so I didn’t get a sense of how the specific standard would be structured, except it will likely have some effects prong involving showing that a map substantially changes the electoral results.

Every justice seemed to think there’s no way that the gerrymander could be cured before November, which raises procedural issues for reversing the injunction. The Court might uphold the denial of the injunction, on the grounds that there’s no irreparable harm, but then establish a standard that would govern the Maryland trial as it goes forward.

Specific justices: The liberals won’t do anything to harm the anti-gerrymandering cause. Alito was dismissive and a vote against. Gorsuch didn’t say much.

In summary, Roberts’s vote might be in play! But we still don’t know what a standard would look like.

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Job opportunity – Legal/Statistical Analyst, Princeton Gerrymandering Project

March 26th, 2018, 4:41pm by brian

The Princeton Gerrymandering Project is hiring a Legal Analyst! The PGP combines law with statistics to develop and explain mathematical tools to detect partisan gerrymandering. This person will join a team with expertise in statistics, law, computational simulation, mathematical rigor, and practical policy.

As the 2020 redistricting looms, the PGP is taking the fight to the states, where we will explore possibilities for ballot- and litigation-based reform. The legal analyst will be responsible for digging into the legal, political, and statistical issues surrounding redistricting in the states we target. She/he will research the regulations governing redistricting, the ways in which the process played out in the last several redistricting cycles, the background politics, and current reform efforts.

Additionally, the legal analyst will keep abreast of redistricting news and scholarship, both legal and statistical. The political, legal, and academic landscape changes rapidly, and upcoming Supreme Court decisions are likely to transform the field. A strong understanding of the field is essential to informing the PGP’s strategic choices and for collaborating with other members of the PGP on computational and statistical projects.

Finally, the legal analyst will co-author academic and popular press articles about PGP methods. She/he will also handle press inquiries and external communications.

The ideal candidate for this job is a strong writer with basic knowledge of courts and the law. She/he will also be familiar and comfortable with discussing both legal and mathematical/statistical issues with academic and lay audiences. This position is suitable for someone between college and graduate or professional school. More experienced applicants are also welcome. In all cases, she/he must be available full-time.

Soon there will be an official job posting, at which time the goals and requirements may be modified slightly. In advance of that, I invite interested people to send me an email at and cc Brian Remlinger ( to describe qualifications and availability.

Comments Off on Job opportunity – Legal/Statistical Analyst, Princeton Gerrymandering ProjectTags: Redistricting

Politics and Polls: Can Trump Actually Shut Down the Mueller Investigation?

March 22nd, 2018, 4:45pm by Sam Wang

As Trump hostility to Mueller’s investigation heats up, can he actually shut it down? On Politics And Polls, I talk to Fordham Law professor and Trump-investigation expert Jed Shugerman about fail-safes that Mueller may have put in place, and legal theories of the case. Listen to the new Politics & Polls!

Oh, and in case you missed them, Julian and I have had some awesome recent episodes: one with the Drive-By Truckers, one with political writer E.J. Dionne, and one with historian Linda Gordon on the resurgence of the KKK in the 1920’s, and what it means for the present day. Quite a range of guests – we’re very pleased with the cool people we have had on!

→ 11 CommentsTags: President · U.S. Institutions

Game over in Pennsylvania!

March 19th, 2018, 3:49pm by Sam Wang

Today came two rulings. First, a three-judge court turned down a challenge to the redrawn Pennyslvania Congressional map. Then, a few hours later, the U.S. Supreme Court did the same.

These were long-shot cases, since they would have involved finding that the Pennsylvania Commonwealth Constitution was in conflict with the United States Constitution, for example if there were an affirmative right to gerrymander in the latter. It would have been tortured logic, and it appears that there were not enough votes on the Supreme Court to go there. This outcome is logically unsurprising…but still a relief.

There was talk about finding a reason to overturn the state court’s decision using Article I, which states that the legislature has the power to set the manner of elections. However, this would go against considerable court precedent. That might fly when the Presidency is at stake (i.e. Bush v. Gore), but to swing half a dozen Congressional seats? As of 2018, no.

So…game over for partisan gerrymandering in Pennsylvania’s Congressional delegation! At least for 2018, and probably 2020. After that…we start over again with the next Census and redistricting.

→ 15 CommentsTags: 2018 Election · 2020 Election · Redistricting

Pennsylvania’s (current) 18th CD: The top of the levee

March 13th, 2018, 9:08pm by Sam Wang

Whoever wins today’s special election to fill the open Congressional seat in Pennsylvania’s 18th District, it wasn’t supposed to be close. It’s part of a statewide partisan gerrymander, a district that a generic Republican ought to win by about 20 points. In November 2016, Donald Trump got 58% to Hillary Clinton’s 39%. The closeness of the race suggests there’s a massive wave of discontent with the Republicans.

If Conor Lamb (D) wins, that doesn’t mean that gerrymanders don’t matter. Instead, it means that even the highest levee can be breached if the wave is high enough. This year’s potential Democratic wave is evidently very high indeed. If this race is near-tied in a district that Donald Trump carried by 19 points in 2016, that is a massive swing – consistent with other special elections in 2018, which have swung by a median of 23 points toward Democrats.

Follow the NYT predictive tracker here, and DailyKos Elections here.

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Climate life events

February 25th, 2018, 9:39pm by Sam Wang

This graph was done using a simple but outstanding app to make climate change personal. [GitHub]

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Introducing the new Pennsylvania Congressional map

February 19th, 2018, 3:20pm by Sam Wang

Here’s the new Congressional map for Pennsylvania, drawn by advisor to the court Nate Persily. I think it’s a landmark contribution to the understanding of partisan fairness, in one of the most politically heterogeneous states in the Union – “Pennsatucky.”

For anyone who’s drawn such maps, this particular one is a pleasure to look at. It does a great job at compliance. It splits 13 counties, less than any plan offered to the court. The only plan that splits fewer counties or municipalities is the “compact D gerrymander” that the Princeton Gerrymandering Project posted over the weekend. So in terms of basic compliance, it wins.

But more importantly, this map undoes the effects of population clustering. As we showed over the weekend, it is just possible within the Pennsylvania Supreme Court’s rules to allow a plan that reaches partisan balance, i.e. a 9 D, 9 R outcome for a 50-50 statewide vote. However, those rules bias the range of possibilities in favor of Republicans, so that a Republican gerrymander – one of the proposals on the table – was also a possibility.

It appears as if the advisor was either trying to achieve partisan balance or build competitive races (as opposed to, say, picking a plan that was in the middle of the range of possible maps). His map – and the one we gave over the weekend – show that even under the constraint of compactness and not splitting political jurisdictions, it is still possible to build a map that treats both parties approximately equally. Notably, he did so while keeping most population centers together. This map passes all three of our tests of partisan asymmetry.

This outcome fits with an unspoken principle in the court’s decision of partisan symmetry: if the two sides swapped vote totals, then their seat totals should be swapped as well. This fundamental principle of fairness underlies our proposed standards for detecting gerrymandering, as described in our amicus brief in the Whitford case.

It is commonly claimed that partisan bias arises naturally from the way that voters distribute themselves. Certainly such a bias could be visible if one drew thousands (or millions) of maps at random. But districting is not a random process. It is done by human beings, and reflects real-life political and social considerations. In that respect, we shouldn’t care about millions of maps; we should only care about one map, the one that is drawn. Persily has shown that it is possible to maintain all the old principles of geographic contiguity, and still create an overall map that does not give either party an undue advantage. In my view, this is a big deal because it shows that the ideal of partisan symmetry can be a primary criterion for drawing a map.

It seems clear that the Pennsylvania GOP made a serious tactical error. The governor and Democratic legislators had offered a plan that would have retained some GOP advantage. The new plan erases that advantage entirely. In our analysis, based on the 2016 vote the new map produces 5 Democratic districts, 7 Republican districts, and 6 tossup districts. The maximum likely performance by Democrats in 2018 would be 11 seats, a gain of 6 seats over their current representation. That gain would be one-fourth of the 24 seats they need to win control of the House of Representatives. Of course, some of those gains could also go away in a later year that was good for Republicans. That’s the point of electoral competition.

→ 28 CommentsTags: 2018 Election · Redistricting