Inspired by this question and it's answers.

With the recent Supreme Court ruling that punts on the issue of political gerrymandering to the individual States, the dissenting opinion makes the following point:

The partisan gerrymanders in these cases deprived citizens of the most fundamental of their constitutional rights: the rights to participate equally in the political process, to join with others to advance political beliefs, and to choose their political representatives. In so doing, the partisan gerrymanders here debased and dishonored our democracy, turning upside-down the core American idea that all governmental power derives from the people. These gerrymanders enabled politicians to entrench themselves in office as against voters’ preferences. They promoted partisanship above respect for the popular will. They encouraged a politics of polarization and dysfunction. If left unchecked, gerrymanders like the ones here may irreparably damage our system of government.

This seems pretty self-evident: in the degenerate case a party could win control of a State Legislature with slightly more than 25% of the popular vote.

However, reading between the lines of the argument in the majority opinion seems to show that in practice stopping political gerrymandering isn't so simple: how do you show that a re-districting is a gerrymander? How much is too much? Do you make some sort of weird proportional guarantee that basically cripples the ability of states to re-district at all?

These seem like reasonable practical issues.

So, for the sake of this question, gerrymandering is obviously bad, but how would you stop it in practice? One could obviously ditch FPTP for a proportional representation system, and while I think that would be a generally good thing it's unlikely to happen in the US. Any other way?

  • Are you looking for practical solutions or for general statements? In the first instance this will likely be opinion based (I support computer controlled districting for xyz, or public panel approval because abc), the second "via the courts" seems to already be happening.
    – Jontia
    Commented Jun 28, 2019 at 14:15
  • It's also worth looking at publicmapping.org/what-is-redistricting/… for when what looks like Gerrymandering is actually required.
    – Jontia
    Commented Jun 28, 2019 at 14:18
  • @Jontia practical solutions. As for opinion-based, any reasonable solution would be welcome, I'm not looking for the "best" one (if such a thing even exists). Commented Jun 28, 2019 at 14:59
  • Easy: projects.fivethirtyeight.com/redistricting-maps
    – Navin
    Commented Jun 29, 2019 at 0:02
  • 2
    @lazarusL It doesn't matter. Don't let perfect be the enemy of good. None of those maps favor one political party over another, so any of them would solve gerrymandering as most people know it.
    – Navin
    Commented Jul 2, 2019 at 1:06

8 Answers 8


Pegden, Procaccia, and Yu have proposed a really cool new method for districting from game theory. In a 2 party system, a pretty fair solution can be reached using a method deriving from the simple concept of "I cut, you choose." A 2/5/18 Washington Post article describes the solution as follows:

The first party divides the state into eight districts (in a way that satisfies all legal requirements) and hands the map to the second party. The second party freezes one of the eight districts drawn by the first party and then divides the unfrozen part of the state into seven new districts. The second party then returns the map to the first party, which then freezes one of the seven new districts, draws six more and hands it back to the second party. This process continues until, after seven rounds, all eight districts have been frozen.

Why is the “I cut, you freeze” protocol fair to both parties? Intuitively, neither party is able to unilaterally shape districts, as each party can only freeze districts drawn by the other party. In fact, we establish mathematically that this protocol can prevent one party from packing a targeted group of voters into a district. This property holds when both parties employ their best possible strategies, which might make use of sophisticated algorithms and detailed information about voters.

This solution is very powerful because it doesn't require any impartiality. It's understood that both parties want to win elections, but they can't game the system by picking a "simple geometric pattern" or "totally impartial commission" that gives them what they want.

  • The problem with this is that it views districting in purely us versus them terms. So it has politicians working with other politicians to make equally bad districts. I would not describe this as "pretty fair" but as unfair for both sides. I'm not sure that it's symmetrically unfair. Democrats, who want to crack their urban districts, would seem to have an advantage over Republicans who want to pack those districts. And this does nothing for third parties. Meanwhile, proportional systems usually allow voters to choose how to aggregate.
    – Brythan
    Commented Jul 4, 2019 at 17:08
  • 1
    @Brythan Winner-take-all districts already screw over 3rd parties.It definitely doesn't advantage one side over the other, that's the beauty of it, there's no advantage in this system to drawing the line first.
    – lazarusL
    Commented Jul 4, 2019 at 19:33
  • 1
    @Brythan can you link to a more detailed explanation of why that is true? It doesn't seem intuitive that that would be the case.
    – lazarusL
    Commented Jul 5, 2019 at 20:07
  • 1
    It's in the quoted matter: "In fact, we establish mathematically that this protocol can prevent one party from packing a targeted group of voters into a district." Note how it says that it prevents packing, which is what Republicans want to do. But it doesn't prevent cracking, which is what Democrats want to do. I don't know that that criticism has been made in the literature yet.
    – Brythan
    Commented Jul 6, 2019 at 1:02
  • 1
    @Brythan I'm still a little fuzzy on how what the Dems and GOP is different. Didn't the Maryland legislature still pack all the most rural Republican friendly voters into one district and then diluted other rural areas with city voters. How is that fundamentally different from North Carolina Republicans packing the most progressive voters into all urban districts and diluting the rural districts with small edges of urban areas?
    – lazarusL
    Commented Jul 6, 2019 at 4:36

Any other way?


The normal suggestions are

  1. An "independent" commission.
  2. A "fair" algorithm.

But who chooses the fair algorithm? The politicians in power. How long does it take before someone realizes that they can gain more power with a "fairer" algorithm that happens to give them more seats. They don't even need to be cynical about it. It's easy for people to convince themselves that the system that gives them an advantage is the fair system.

The United States has states with "independent" commissions.

One example is Iowa. Iowa is basically a 50-50 state. Occasionally one party or the other might win 55-45, but they don't win 62.5 to 37.5 or better in aggregate (individual candidates may do that well). Since the last redistricting, they've had 3-1 delegations. Why? Because the independent commission cracks both parties such that they are mixed with the other party. So in a wave election, it produces results out of proportion with the underlying vote. I.e. it amplifies the result.

Or take California. California votes Republican around 34%. So it should have around eighteen Republican seats. In actuality, it's ranged between seven and thirteen for the last decade. The current discrepancy of eleven is as large as in any state in the nation.

If the measure of fairness that one uses is a proportional result, then the only fair way to get it is through a proportional system. Any other method will sometimes fail to produce a proportional result.

  • 2
    "If the measure of fairness that one uses is a proportional result, then the only fair way to get it is through a proportional system." Fairness is not black and white. You can have "more fair" without having to go all the way to "perfectly fair". Commented Jun 28, 2019 at 20:53
  • 2
    Also, this seem to beg the question. You're talking about a hypothetical system designed to produce proportional representation, and you reasonably point out flaws in such a system. But why presume that such a system is the only possible alternative to political gerrymandering? This is the crux of the Supreme Court's disagreement. The dissent agrees that a “fairness” standard is unworkable, but proposes a different sort of standard that the majority rejects. Your objections to a “fairness” standard are correct, but largely beside the point.
    – Thom Smith
    Commented Jun 28, 2019 at 23:41
  • 2
    Iowa's kind of a bad example because 3-1 vs 2-2 is a normal discretization error. Commented Jun 29, 2019 at 4:36
  • I assume you're talking about US House delegations? I wonder if you could make that a bit clearer; as state legislatures are also affected by gerrymandering. Commented Jun 29, 2019 at 6:24

The dissent in the court case referenced by the question addresses this at some length. It takes care to distinguish two questions:

  1. Is a districting map fair to members of all parties?
  2. Does the map have the purpose and effect of diluting representation based on party affiliation?

The dissent agrees with the majority that the first question is not justiceable. But it identifies reasonable standards for adjudicating the second, based on standards applied by the district courts.

Some relevant excerpts from the dissent (citations omitted):

Page 15:

Over the past several years, federal courts across the country—including, but not exclusively, in the decisions below—have largely converged on a standard for adjudicating partisan gerrymandering claims (striking down both Democratic and Republican districting plans in the process). See also []. And that standard does what the majority says is impossible. The standard does not use any judge-made conception of electoral fairness—either proportional representation or any other; instead, it takes as its baseline a State’s own criteria of fairness, apart from partisan gain. And by requiring plaintiffs to make difficult showings relating to both purpose and effects, the standard invalidates the most extreme, but only the most extreme, partisan gerrymanders.

Page 16:

Start with the standard the lower courts used. ... both courts (like others around the country) used basically the same three-part test to decide whether the plaintiffs had made out a vote dilution claim. As many legal standards do, that test has three parts: (1) intent; (2) effects; and (3) causation. First, the plaintiffs challenging a districting plan must prove that state officials’ “predominant purpose” in drawing a district’s lines was to “entrench [their party] in power” by diluting the votes of citizens favoring its rival. []. Second, the plaintiffs must establish that the lines drawn in fact have the intended effect by “substantially” diluting their votes. []. And third, if the plaintiffs make those showings, the State must come up with a legitimate, non-partisan justification to save its map. See []. If you are a lawyer, you know that this test looks utterly ordinary. It is the sort of thing courts work with every day.

(In that last sentence, Kagan emphasizes that the standard need not be mathematically precise. The North Carolina gerrymander was created using sophisticated algorithms to precisely maximize one party's electoral gains at the expense of the other, so the notion of a counter-algorithm to set fair limits is intuitively appealing. But this is not how legal standards typically operate; phrases like "predominant purpose", "substantially", and "legitimate" are the norm, and exact quantitative formulas are the exception. As Kagan writes on page 27, "...courts all the time make judgments about the substantiality of harm without reducing them to particular percentages. If courts are no longer competent to do so, they will have to relinquish, well, substantial portions of their docket.")

Page 22-24:

Contrary to the majority’s suggestion, the District Courts did not have to—and in fact did not—choose among competing visions of electoral fairness. That is because they did not try to compare the State’s actual map to an “ideally fair” one (whether based on proportional representation or some other criterion). Instead, they looked at the difference between what the State did and what the State would have done if politicians hadn’t been intent on partisan gain. Or put differently, the comparator (or baseline or touchstone) is the result not of a judge’s philosophizing but of the State’s own characteristics and judgments. The effects evidence in these cases accepted as a given the State’s physical geography (e.g., where does the Chesapeake run?) and political geography (e.g., where do the Democrats live on top of each other?). So the courts did not, in the majority’s words, try to “counteract ‘natural’ gerrymandering caused, for example, by the urban concentration of one party.” []. Still more, the courts’ analyses used the State’s own criteria for electoral fairness—except for naked partisan gain. Under their approach, in other words, the State selected its own fairness baseline in the form of its other districting criteria. All the courts did was determine how far the State had gone off that track because of its politicians’ effort to entrench themselves in office.

... In North Carolina, for example, Democratic voters are highly concentrated in cities. That fact was built into all the maps; it became part of the baseline. See []. On top of that, the maps took the State’s legal landscape as a given. They incorporated the State’s districting priorities, excluding partisanship. So in North Carolina, for example, all the maps adhered to the traditional criteria of contiguity and compactness. See []. But the comparator maps in another State would have incorporated different objectives—say, the emphasis Arizona places on competitive districts or the requirement Iowa imposes that counties remain whole. See []. The point is that the assemblage of maps, reflecting the characteristics and judgments of the State itself, creates a neutral baseline from which to assess whether partisanship has run amok. Extreme outlier as to what? As to the other maps the State could have produced given its unique political geography and its chosen districting criteria. Not as to the maps a judge, with his own view of electoral fairness, could have dreamed up.

Page 25:

According to the majority, “it does not make sense to use” a State’s own (non-partisan) districting criteria as the baseline from which to measure partisan gerrymandering because those criteria “will vary from State to State and year to year.” []. But that is a virtue, not a vice—a feature, not a bug. Using the criteria the State itself has chosen at the relevant time prevents any judicial predilections from affecting the analysis—exactly what the majority claims it wants. At the same time, using those criteria enables a court to measure just what it should: the extent to which the pursuit of partisan advantage—by these legislators at this moment—has distorted the State’s districting decisions. Sure, different non-partisan criteria could result, as the majority notes, in different partisan distributions to serve as the baseline. []. But that in itself raises no issue: Everyone agrees that state officials using non-partisan criteria (e.g., must counties be kept together? should districts be compact?) have wide latitude in districting. The problem arises only when legislators or mapmakers substantially deviate from the baseline distribution by manipulating district lines for partisan gain. So once again, the majority’s analysis falters because it equates the demand to eliminate partisan gerrymandering with a demand for a single partisan distribution—the one reflecting proportional representation. See []. But those two demands are different, and only the former is at issue here.

  • 2
    Please add a link to the source you're quoting.
    – JJJ
    Commented Jun 28, 2019 at 15:30
  • "Still more, the courts’ analyses used the State’s own criteria for electoral fairness—except for naked partisan gain." This seems to be the crux of the problem. The federal courts were essentially making up a requirement that didn't exist in law they could enforce.
    – jpmc26
    Commented Jun 28, 2019 at 19:48
  • 2
    The underlying requirement is the Constitution itself. It has long been established that a map drawn by the states may infringe upon the constitutional rights of that state's inhabitants and that the federal judiciary has the power to reject such maps and require that they be redrawn. (See Baker v. Carr.) The majority opinion did not contest this, nor did they contest the finding that the gerrymandering in the case implicated Constitutional rights. Rather, they held that it was impossible for the court to come up with an appropriate test. The dissent disputes this, providing such a test.
    – Thom Smith
    Commented Jun 28, 2019 at 20:18

Use a proportional voting system. As every vote counts the same, the shape of voting districts has no effect on the election results. This removes the incentive for Gerrymandering.

  • I feel this should provide more information as the idea is also found in the last paragraph of Brythan's answer.
    – Alexei
    Commented Jun 29, 2019 at 9:02
  • ...and the last paragraph of the question itself. Commented Jun 29, 2019 at 11:55

You may stop gerrymandering by restricting all districts to a polygon of a limited number of sides. For example, if all districts are 4 sided polygons, then all districts are rectangles. Of course there would have to be language to automatically subtract any area outside of a states geographical boundaries if the district extends beyond a border. My preferred number is at most a 5 sided polygon. This keeps districts very simple and understandable.

  • However that flies out the window in any scenario where you want positive gerrymandering (e.g. to ensure that a majority minority district has a proper representative) or population density difference. You don't need the districts to have a fixed number of sides, just require it to be a convex polygon. Commented Jun 28, 2019 at 19:36
  • Modern gerrymandering is done using sophisticated optimization algorithms, and those algorithms could easily be constrained to polygons. Is there research showing that this would effectively prevent partisan gerrymanders?
    – Thom Smith
    Commented Jun 28, 2019 at 19:52
  • 3
    Positive gerrymandering is subjective, and still gerrymandering. I'm OK with convex polygons, but 3-8 sides sounds simpler. Yes all current districts are polygons via algorithms but they have hundreds of sides to snake around each other. Research isn't required as it's obvious square districts cannot be gerrymandered to such a great degree.
    – Chloe
    Commented Jun 28, 2019 at 19:56
  • 5
    This doesn't actually solve anything. It makes districts have more reasonable shapes, which reduces the level of precision that can be used in a gerrymander, but it still doesn't prevent choosing and positioning the shapes so that one party is disproportionally advantaged. As an example, look at the "Compact but Unfair" example in the image at washingtonpost.com/news/wonk/wp/2015/03/01/….
    – Bobson
    Commented Jun 28, 2019 at 20:02
  • 5
    @Chloe Convex isn't a reasonable criterion. For example any division that puts Brooklyn and Manhattan in separate districts is necessarily non-convex because of the shape of the East River. If you force convexity there, you're forced to accept some random slivers of Manhattan in the Brooklyn district or vice-versa. Commented Jun 28, 2019 at 20:59

So, for the sake of this question, gerrymandering is obviously bad, but how would you stop it in practice?

  1. Assemble a coalition of people who think gerrymandering is bad in your state, and get them all to run for public office in the state legislature.

  2. Win all of those elections such that you have majority control of the legislature.

  3. Write legislation that redistricts your Congressional districts however you want, subject to federal limitations.

In other words, you un-gerrymander a state exactly the way that people gerrymandered it in the first place.

  • 5
    The question is how would you stop it, not how would you undo it. Redistricting once only fixes the problem until the next time they get gerrymandered. Commented Jun 28, 2019 at 20:49
  • 1
    @DavidRicherby These steps are still required regardless of that distinction. If you insist this is insufficient because a future legislature can undo it, then the only correct answer to the question is to permanently end representative democracy at the state level.
    – Joe
    Commented Jun 28, 2019 at 21:58

I would require that every district be wholly within an incorporated place, or contain whole incorporated places. I want the districts to be simply connected. I would have striving for convexity, but limitedly, because real incorporated places are seriously not convex. Here in NW Ohio Toledo, Sylvania, Waterville, and others, after years of annexation look like squared-off amoebae, and Toledo is also not simply connected. If census blocks, in spite of the effective randomness of these borders, follow them, then use of the blocks is all right with me. I maintain this although there are indeed incorporated places that are somehow gerrymandered: in NE NJ there is a small wholly commercial-free place. Every building, aside from the tiny city hall, is a dwelling house. There is also no post office. At least such places cannot be big, or numerous.

  • What would you do with people that don't live in incorporated places, then? Commented Jun 29, 2019 at 6:28
  • Especially when certain areas strongly fight incorporation. Commented Jul 1, 2019 at 13:44

You can prevent gerrymandering by having a neutral, algorithmic criterion for drawing the districts. For example, One could define the best districting plan to be the one that produces the lowest possible average output from the following procedure:

"Choose a district at random. Then choose two random voters in your district. Output the crow-flies distance between their home addresses."

When it comes time to redistrict, let anyone submit a proposal. Compute the above for all proposals. The lowest answer wins.

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