“The redistricting process may seem arcane and academic, even negligible, but it is a foundation of representative democracy. “There are all these voter-suppression laws being passed around the country, but in a lot of ways those are like a death by a thousand cuts that make it harder in incremental ways to vote,” Michael Li, a lawyer at the Brennan Center for Justice, told me. “But gerrymandering is a little bit like a nuclear bomb that levels everything in its place. Because it means that even if you jump through all the hurdles—the I.D. requirements, the elimination of drop boxes, the shortening of voting hours—and are able to vote, your vote doesn’t matter.” Once the basic tenets of democracy—one person, one vote in a government of the people—are subverted, other devolutions follow. This is why Congress is so often out of step with public opinion on issues like gun control and immigration reform. It is what we are now seeing with the curtailing of abortion rights: a group of conservative Supreme Court Justices, three of whom were appointed by a President who was not elected by a popular majority, are poised to overthrow a precedent favored by nearly seventy per cent of the country. And, once they do, conservative legislators in states across the country will be positioned to impose their own deeply unpopular beliefs on their constituents.”
This very useful analysis explains how the FTVA’s rebuttable presumption of unlawful gerrymandering works and identifies which new congressional maps would trigger that presumption. Unsurprisingly, maps drawn by legislators are much more likely to trigger the presumption than maps drawn by commissions or courts. Also unsurprisingly, both Democratic and Republican legislators draw highly biased maps when they have the opportunity to do so.
We found that states where Republicans control the state legislatures draw congressional maps that disproportionately favor Republican candidates. For instance, in Georgia, North Carolina, Ohio and Texas, Republican candidates are likely to win more seats than if they won seats in proportion to their share of the statewide vote. The Ohio map, for example, makes it likely that Republicans will win two more seats than you would expect, given that in the elections since 2016, 55 percent of voters pulled the lever for Republicans and 45 percent for Democrats.
Indiana, Iowa and Utah, where Republican-controlled legislatures draw the maps, will likely have similar results, with Republican candidates winning one more seat than you would expect from their proportion of the vote. Under the FTVA, if someone brought suit and the federal courts couldn’t assess the map before the state’s 2022 primaries, the courts would have the power to put in place a temporary map or postpone the primary.
Democrats do the same when they draw maps. In blue states such as Maryland, Massachusetts and Oregon, Democratic-controlled legislatures draw maps that are just as likely to tilt districts to their party’s advantage. For instance, Illinois’ map is a mirror image of North Carolina’s, drawn to systematically advantage Democrats — likely giving them about 2.5 more congressional seats than their usual proportion of statewide votes would suggest.
In some states, however, commissions draw the maps. Four states — Arizona, California, Colorado and Michigan — have created commissions that draw districts independently from the legislature. Our analysis finds that the commissions in California, Colorado and Michigan successfully balanced various competing criteria and created the most balanced maps of the cycle so far. The plan in Arizona would trigger the FTVA’s presumption, though the independent commission there might be able to rebut that presumption.
One of the last decade’s most interesting redistricting developments was the adoption of explicit partisan fairness criteria by Michigan and Ohio (sites of two of the 2010s’ most egregious gerrymanders). In Michigan, the new independent commission is required to draw districts that don’t “provide a disproportionate advantage to any political party.” “A disproportionate advantage,” the state constitution continues, “shall be determined using accepted measures of partisan fairness.” In Ohio, if the state legislature enacts a congressional plan by a majority (not a three-fifths supermajority) vote, then the plan must not “unduly favor or disfavor a political party.” For state legislative maps, “the statewide proportion of districts whose voters . . . favor each political party shall correspond closely to the statewide preferences of the voters of Ohio.”
So how have these criteria fared so far? In Michigan, the independent commission decided to consider four measures of partisan fairness (the efficiency gap, deviation from proportional representation, the mean-median difference, and the winning margin difference). The commission also specified that these metrics would be calculated using an aggregate of statewide elections from 2012 to 2020. The commission hasn’t yet finalized its plans but its draft maps, drawn to satisfy this criterion, are dramatically fairer than their predecessors. At the congressional level, for example, the commission’s three draft maps all have efficiency gaps around 1%—compared to an efficiency gap of almost 20% (in a Republican direction) for the 2010s plan.
In Ohio, on the other hand, the Republican-dominated commission flouted the new partisan fairness requirement. Over the last decade, Republican candidates have won an average of 55% of the vote in statewide races. Yet the commission’s state house plan has a Republican seat share of 67%, and its state senate plan has a Republican seat share of 69%. The commission’s required explanation for its plans was also risible. It conceded that, on average, Republican candidates have won just a narrow majority of the statewide vote in recent years. But, the commission continued, “Republican candidates won thirteen out of sixteen of those elections resulting in a statewide proportion of voters favoring statewide Republican candidates of 81% and a statewide proportion of voters favoring Democratic candidates of 19%.” Therefore, “the statewide proportion of districts whose voters favor each political party corresponds closely to the statewide preferences of the voters of Ohio.”
The sleight of hand here is obvious. The commission substituted the proportion of races won by Republican candidates (81%) for the proportion of the vote received by Republican candidates (55%). The latter figure—Republican statewide vote share—represents “the statewide preferences of the voters of Ohio” under both the Ohio Constitution and all accepted methods for assessing partisan fairness. The former figure—Republican candidates’ win rate—is simply irrelevant. Using that flawed statistic, one would have to conclude that the commission’s plans are significantly biased in a Democratic direction. After all, 31% to 33% of the plans’ districts are Democratic—far higher than the 19% of Democratic candidates who prevailed in statewide elections in the 2010s. If Republicans had managed a clean sweep of statewide elections over the last decade, under the commission’s logic, they would be entitled to every single state legislative seat.
What accounts for Michigan’s and Ohio’s very different experiences (to date) with partisan fairness criteria? Most likely, the identity of the line-drawing institution. Michigan’s commission is independent of political actors and balanced among Democratic, Republican, and Independent members. These commissioners have no reason not to faithfully follow all state constitutional requirements. In contrast, Ohio’s commission is composed entirely of politicians and has five Republican and two Democratic members. This Republican supermajority has every incentive to gerrymander (and then to concoct implausible accounts of how its actions actually comply with legal criteria).
The implication for reformers is that, to achieve partisan fairness without judicial involvement, partisan fairness criteria should be paired with structural change—that is, the adoption of a truly independent redistricting commission. As Ohio’s experience demonstrates, partisan fairness criteria alone, unaccompanied by structural change, may easily be ignored by political actors. To be sure, state courts may ultimately insist on compliance with Ohio’s partisan fairness criteria. (Ohio’s new plans immediately prompted a flurry of lawsuits.) But redistricting litigation is costly and time-consuming. Its outcome is also never certain, even given as clear a violation as that presented by Ohio’s facts, due to the issue’s intense politicization. Whenever possible, it seems better to avoid courts and to rely on the structure of the redistricting process itself to prevent gerrymandering.
The new Freedom to Vote Act has many interesting pieces, but I want to focus here on the rebuttable presumption of gerrymandering that’s at the core of the Act’s redistricting provisions. In a nutshell, this presumption kicks in if a court finds that an enacted plan (1) exceeds a certain quantitative threshold (2) with respect to certain prior elections (3) according to certain measures of partisan fairness. If the presumption is triggered, a plan can’t be used unless a court ultimately concludes that, actually, the plan was not “drawn with the intent” and does not have “the effect of materially favoring or disfavoring any political party.”
Threshold: I’ll now unpack the different parts of the rebuttable presumption, starting with the quantitative threshold. It’s defined as “partisan advantage or disadvantage in excess of 7 percent or one congressional district, whichever is greater.” A bias score can be converted from a percentage to a number of seats simply by multiplying it by the size of a state’s congressional delegation. For example, Washington has 10 congressional seats. So if a Washington congressional plan has a pro-Democratic bias of 7%, that’s equivalent to a pro-Democratic bias of 0.7 seats.
In practice, the one-seat threshold will be the binding constraint for smaller states (those with 14 or fewer congressional seats). That’s because, in those states, a bias of one seat is always larger than a bias of 7%. On the other hand, the 7% threshold will be the binding constraint for larger states (those with 15 or more congressional seats). That’s because, in those states, a bias of 7% is always larger than a bias of one seat. Note also that these thresholds don’t allow for any rounding. A bias of 1.1 seats (in a smaller state) or 7.5% (in a larger state) exceeds the limit.
Prior elections: Of course, partisan bias doesn’t exist in the abstract. It has to be calculated using particular election data. The Act specifies exactly what data should be employed for this purpose: the two most recent presidential elections and the two most recent Senate elections in a state. An enacted plan’s bias has to be computed with respect to each of those four elections. The plan is presumptively unlawful if it exceeds the applicable threshold (7% or one seat) in “2 or more of the 4 elections assessed.”
Consider Washington again. Its recent presidential and Senate elections have been remarkably consistent. In 2016, Hillary Clinton and Patty Murray each won 59% of the two-party vote. In 2018, Maria Cantwell won 58% of the two-party vote. And in 2020, Joe Biden won 60% of the two-party vote. These four elections provide the data to be used to evaluate any new Washington plan. Any new plan can exceed a bias of one seat in at most one of the four elections. Any new plan that exceeds a bias of one seat in two or more of the four elections is presumptively invalid.
Partisan fairness measures: This leaves the question of how to measure partisan bias. The Act states that the only metrics that can be consulted are “standard quantitative measures of partisan fairness that relate a party’s share of the statewide vote to that party’s share of seats.” The term “standard” does the work of excluding newfangled metrics that aren’t accepted in the academic literature and may even have been devised for litigation purposes. More significantly, the other italicized phrase excludes metrics that don’t specify an optimal seat share for a party’s given statewide vote share. Partisan asymmetry is thus excluded as a metric since it permits any vote share to result in any seat share (as long as, if the parties’ positions were flipped, the same seat share would follow from that vote share). The mean-median difference and the declination are also excluded because they’re not calculated using a party’s seat share.
On the other hand, the efficiency gap is plainly included. In its preferred form, it’s calculated using the formula S – (2 * V), where S is the difference between a party’s seat share and 50% and V is the difference between a party’s statewide vote share and 50%. Also included, at least as long as it’s considered a “standard” measure, is a plan’s deviation from proportional representation. That deviation is computed by simply subtracting a party’s seat share from its statewide vote share.
In situations where the efficiency gap and disproportionality both point in the same direction, consulting two metrics instead of one is unproblematic. What about when they disagree—when a plan’s efficiency gap in a given election is above (below) the threshold but a plan’s disproportionality is below (above) that line? This is where the Act, admirably detailed as it is, finally runs out of steam. In my view, the better approach is to count a strike against a plan only when it exceeds the applicable threshold under both the efficiency gap and disproportionality. If a plan is above the threshold using one measure, but below it using another, I wouldn’t call that a strike. In effect, this approach lets states choose whether they prefer to aim for a low efficiency gap or for low disproportionality. States wouldn’t be compelled to achieve a low efficiency gap and low disproportionality simultaneously—an impossible goal in certain circumstances.
Return to Washington one more time. As noted above, Democratic candidates in the four reference elections received about 60% of the two-party vote. Given this statewide Democratic vote share, minimizing the efficiency gap would entail Democrats winning seven of ten seats, while minimizing disproportionality would entail Democrats winning six of ten seats. Under my preferred reading of the Act, Washington could use either of those benchmarks depending on whether the state wanted a modest winner’s bonus for the majority party (provided by the efficiency gap) or no winner’s bonus at all (per disproportionality). Many outcomes—like nine or more, or four or fewer, Democratic seats—would result in both efficiency gaps and disproportionality values above the applicable threshold. But a considerable range of other outcomes would be allowed because they would produce a sufficiently low score on at least one metric.
Yesterday, Colorado became the first state to publish a draft congressional map. PlanScore’s analysis of the map is below. It would be slightly skewed in a Republican direction, with an expected efficiency gap of 2.5%, an expected partisan bias of 4.0%, and an expected mean-median difference of 1.4%, all in Republicans’ favor. Note also that one district (the Seventh) is predicted to be barely Republican; if that district flipped then the map would be tilted modestly toward Democrats.
Illinois released draft state legislative district plans on Friday evening. Here’s PlanScore’s analysis of the state house map (hat tip to Brian Amos for converting the map into a usable digital format). It’s predicted to have a pro-Democratic efficiency gap of 2%. That’s somewhat more pro-Democratic than the existing state house plan, which had an average efficiency gap of 3% in a Republican direction from 2012 to 2018. But it’s still a low figure not indicative of a significant bias in either party’s favor.
Notably, Illinois’s draft state house map pairs this small efficiency gap with numerous noncompact districts, especially in and around Chicago. It’s likely that if the map’s districts were less oddly shaped, the map would be considerably more tilted toward Republicans. The map thus squarely presents the vexing issue of redistricting baselines. Is partisan symmetry the right benchmark? In that case, the map is exemplary since it should accurately translate the partisan preferences of Illinois voters into legislative seats. Or is the baseline what a redistricting process would produce if it ignored election results and prioritized nonpartisan criteria like compactness and respect for political subdivisions? If so, the map is probably skewed substantially in a Democratic direction (though further analysis would be necessary to prove that point).
My friend and NYU colleague Rick Pildes, anticipating the Supreme Court’s ruling in the Arizona redistricting case, argues strongly for the Court to let independent redistricting commissions flourish. The question presented – – whether “legislature” can be read to mean an independent, unelected body to which complete redistricting authority is delegated – – strikes Rick as somewhat beside the point.
The Framers could not have thought about this question, Rick writes, and so could not have ruled out this institutional innovation. While “not naïve about the risk that officeholders would try to aggrandize their own power”, they “didn’t have in their mental toolbox the possibility of the kind of specialized, relatively independent institutions that later emerged for tasks like drawing election districts or regulating other aspects of the democratic process.” Other democracies have worked successfully with these institutions, and Rick contends that ours should be able to do so as well, as an effective means of addressing partisan self-interestedness in the drawing of district lines.
We will see Monday, of course, how all this goes. But Rick’s interesting argument relies on a few assumptions that merit a close look.