When the Wisconsin Supreme Court tossed the state’s legislative district maps in December 2023, they invited the legislature and governor to once more seek an agreement on state legislative maps. The Court also simultaneously solicited proposed remedial maps from the parties to the original court case—one of whom was Gov. Evers himself.

The Court ultimately accepted submissions from six parties, 4 liberal or Democratic and 2 conservative or Republican. Having had the chance to review all the proposals and fearing what the Court’s new liberal majority might do, Republican legislators suddenly found themselves in the unexpected position of supporting Evers’ own proposal. On February 13, both houses of the legislature passed Evers’ map submission, with near uniform Republican support and only one vote in each chamber from Democrats.

Republicans explained their sudden support for Evers map as simply picking the worst of several bad options. In Senator Van Wanggaard’s words, “Republicans were not stuck between a rock and hard place. It was a matter of choosing to be stabbed, shot, poisoned or led to the guillotine. We chose to be stabbed, so we can live to fight another day.”

As I write this, Gov. Evers has not yet signed these maps; although, he has indicated he likely will.

The differences between the partisan lean of Evers’ plan and the three other Democratic-aligned proposals are small but measurable. The Court’s consultants calculated separate partisan bias scores and mean-minus-median-gaps for each plan in their report. For each measure, Evers map is not the best (of the four) for Republicans in either house, but it does have the most favorable Republican score when averaged across both houses.

The consultants also calculate each plan’s “majoritarian concordance,” or the reliability with which it converts an electoral majority into a legislative majority. Considering both houses across 13 statewide races since 2016, the Evers map fails the majority concordance standard 6 times—all in instances where a losing GOP candidate would’ve still won a majority of legislative seats.[1] No other plan fairs quite so well for Republicans.

Another benefit to Republicans is a small reduction in paired incumbents, relative to the other Democratic-aligned plans. The governor’s plan places 25 Republican Assembly incumbents into a district with another incumbent, compared to between 27 and 31 in the other plans. In the Senate, the Evers plan pairs 1 more Republican incumbent than the Senate Democrat’s proposed map, but fewer than either the Law Forward or Wright proposals.[2]

These partisan differences between the Democratic-aligned plans appear, if anything, smaller in the 2022 elections, when the Evers map would’ve performed very similarly to the Law Forward plan. The graphic below compares the partisan lean of the tipping point seat in each house under three different election scenarios.

The rightmost graph shows the share of the vote won by Tony Evers in his reelection campaign. Evers won the state by 3.4 percentage points, enough to give him a majority of the seats in both houses under all four of the Democratic-aligned proposals. (Note: These statistics cover all 33 state senate districts).

The middle graph shows the share of the vote won by Ron Johnson in his reelection campaign. Johnson won the state by one percentage point. That narrow victory would’ve won a majority of the seats in both houses under the Evers and Law Forward plans. Johnson still would’ve narrowly lost both houses under the plan submitted by the Wright Petitioners. Under the Senate Democrats map, Johnson would’ve won a majority of seats in the Assembly and lost a majority in the state senate.

Of course, state legislative races are decided by their own candidates—not top of the ticket races. We can’t simply add up state legislative votes in new districts, because many of the old races were not contested by both parties. Instead, I employ a statistical model using top-of-the-ticket races to estimate state legislative results, had both parties run candidates. The results of that model are shown in the leftmost graph. In general, state legislative Republicans did about 1 point better than Ron Johnson.

Indeed, under my modeled estimate of 2022 state legislative races, Republicans would’ve likely held a majority in every house of every plan, except for the state senate in the Senate Democrats proposal. (Again, this considers all 33 seats, not just the 17 odd-numbered districts being elected in 2022).

The 2022 result is not a prediction of 2024. The larger presidential electorate, heightened attention, greater fundraising, and variable incumbency effects may change the contours of those legislative races in consequential ways.

Still, these three election scenarios give a reasonable sense of the range of outcomes in recent Wisconsin elections. With that in mind, here are graphs showing the lean of each legislative seat under the Evers proposal compared with the previous map.

In these graphs, each tick mark shows the partisan lean of one seat. The larger, red tick mark shows the tipping point seat—the one that determines majority control. This is another way of visualizing the statistics I discussed above. In both houses, the tipping point seat was won by both Gov. Evers and Senator Ron Johnson in their 2022 reelection campaigns. State legislative Republicans did slightly better than Johnson, but even in that scenario, the tipping point seat is far more competitive than in any scenario under the old maps.

Here is a greatly simplified version of the above graph. In these graphs, I have simply counted the number of seats leaning to each party by double and single digit margins, under each scenario. The first row shows the Evers map, the second row shows the previous maps.

Under the old maps, Ron Johnson won a double-digit victory in 55/99 Assembly districts and 19/33 Senate districts. That falls to 46 and 15, respectively, under the Evers proposal—short of a majority.

Under all three scenarios and in both houses, the Evers map creates a situation where majority control will be decided by a set of more competitive districts.

Click the image below to open an interactive map where you can view the Evers map and the previous district boundaries, with the districts shaded by my modeled 2022 legislative margin. For simplicity’s sake, the rest of this discussion will reference only that election scenario.

The Evers map creates 42 Assembly districts with a double-digit Democratic lean and 4 districts with a single-digit lean. Here are where those changes take place.

• The south central region now includes 16 D-leaning seats, up from 12 previously. None of these are particularly competitive.
• Racine/Kenosha now include 4 D-leaning seats, up from 3.
• The Milwaukee metro includes 14 double-digit D-leaning seats, up from 13. The area retains 1 district with a single-digit Democratic lean.
• The City of Sheboygan is unified, becoming a district with a single-digit Democratic lean.
• Oshkosh/Neenah/Appleton are drawn to include 3 D-leaning seats, rather than 2.
• The Eau Claire area is drawn to include 2 D-leaning seats, rather than 1.
• Northwestern Wisconsin is redrawn to include one D-leaning seat, stretching along the coast from Superior to Ashland.
• The La Crosse area is drawn to include 2 D-leaning seats, rather than 1.

To win a majority in November 2024 under the Evers map, Democrats could win all of the seats which lean toward them, plus four of the 7 districts with a single-digit Republican lean. The most likely targets include districts 61 (SW Milwaukee suburbs), 88 and 89 (both in the Green Bay area), and either 85 (Wausau) or 30 (Hudson).

Similarly, to win a majority in the state senate, Democrats would need to win the 10 seats with a double-digit Democratic lean, all 6 seats with a single digit lean in their favor, and one of the two seats with a single-digit Republican lean. Both of those seats are in the Milwaukee suburbs. District 21 stretches from Racine, through Oak Creek and Franklin, up to the southwestern part of the city. District 8 includes much of Milwaukee County’s north shore, as well as southern Ozaukee County.

Because only even-numbered districts will hold election in 2024, I see essentially no chance of Democrats winning a majority this November. However, Democrats have three likely pickup opportunities in 2024 with the Evers senate map—districts 14 (NW of Madison), 18 (Fox Valley), and 30 (Green Bay). Any one of these pickups would end the GOP supermajority in the upper chamber. Winning all of them will put the senate majority very much in play during the 2026 cycle.

[1] These races are Secretary of State 2022 and President 2020 among Assembly seats as well as AG 2018 and Governor 2018 among both Senate and Assembly seats.

[2] Incumbent pairing statistics are from page 13 of the Legislature’s response brief.

Background

The Wisconsin Supreme Court enjoined the further use of Wisconsin’s existing state legislative maps in any future election when it ruled on December 22, 2023 that the current maps are unconstitutional because they include noncontiguous districts. The state constitution requires “[Assembly] districts to be bounded by county, precinct, town or ward lines, to consist of contiguous territory and be in as compact form as practicable” (Wis. Const., art. IV, sec. IV).

Previously, this provision had been interpreted to allow physically separated sections of a single municipality to be placed in a single district, even if this meant that the district, taken as a whole, lacked contiguity.

The 2023 ruling rejected this flexible definition of contiguity in favor of a strictly literal rule. “[F]or a district to be composed of contiguous territory, its territory must be touching such that one could travel from one point in the district to any other point in the district without crossing district lines.” Clarke v. Wisconsin Elections Commission, 2023 WI 79, ¶ 66. Literal islands don’t violate this requirement. “A district can still be contiguous if it contains territory with portions of land separated by water.” Id., ¶ 27.

Extent of noncontiguity

Seven proposed redistricting plans were submitted to the Supreme Court on January 12, 2024, as discussed in an earlier post. One of them—that of the Democratic Senator Respondents—includes several Assembly districts with noncontiguous land areas.

In an Expert Report submitted to the Wisconsin Supreme Court in support of the remedial maps proposed by the Democratic Senator Respondents, Kenneth Mayer maintains that these districts should not be counted as noncontiguous. “The remaining cases of apparent non-contiguity stem from ward fragments resulting from errors in the underlying Census data, which the parties have agreed should not be counted as noncontiguous” (p. 7 of the report). I discuss below whether this data stipulation has any relevance to territorial contiguity.

The noncontiguous Assembly districts are the 44th, 45th, 47th, 48th, 91st, 92nd, and 98th. In total, the unconnected segments include 34 census blocks, of which two are populated according to the 2020 census count. The populated blocks are “550250008001000” in AD48 (pop. 88) and “550350008021018” in AD92 (pop. 14). The remaining blocks are generally tiny strips of land and in any event are unpopulated.

The redistricting plans submitted to the Wisconsin Supreme Court are defined by block assignment files—spreadsheets which list each census block in Wisconsin, along with the district to which it is assigned. I obtained the block assignment files for this plan from links shared by Senate Minority Leader Hesselbein on X on January 12^th.

I measure district noncontiguity by matching the block assignment files to the Census Bureau’s block GIS file. Then, I measure the adjacency of each census block and identify the components of the resulting network. Replication code is available here.

The following graphics show the noncontiguous sections of each Assembly district. Each block in the main component of the district is outlined in blue. Any disconnected blocks are outlined in red. Click here to view a web page with interactive web maps.

The Joint Stipulation

On January 2, the parties to the case filed a joint stipulation describing a series of deviations, agreed to by all parties, from the official redistricting data.

The stipulation mainly deals with 216 ward fragments, themselves including nearly 300 blocks, with incorrect ward or municipality labels. The incorrect labels seem to originate with the original Census Bureau data. This matters because the parties don’t want to be penalized for splitting a ward (or municipality) when, really, it is the label that is incorrect. In the stipulation, the parties agreed on a consistent way to correct and handle these ward and municipality designations.

The position of the Democratic Senator Respondents is that this stipulation also means that the specified blocks should not be counted as physically noncontiguous with the rest of the district.

Here are the relevant paragraphs from the Joint Stipulation. In his report (p. 7 & n.6), Mayer cites paragraphs 8 and 9. I also include paragraph 7, which may be relevant.

7. All parties agree that the Franklin ward and the 215 additional ward fragments identified in Appendix A do not reflect true municipal-ward “islands,” that is, noncontiguous territory which is separated by the territory of another municipality from the major part of the municipality to which it belongs, see Wis. Stat. § 5.15(1)(b), (2)(f)(3).

8. All parties agree that detaching any of the 216 ward fragments identified in Appendix A from the rest of the ward to which it is assigned in the August 2021 Redistricting Dataset will not count as a ward split when evaluating a proposed remedial map.

9. All parties agree that any of the 216 ward fragments identified in Appendix A will be considered part of the municipality to which the August 2021 Redistricting Dataset and the 2020 Census Redistricting Data assigned it, regardless of whether that assignment may have been due to error in the U.S. Census data, when evaluating a proposed remedial map.

Paragraphs 8 and 9 address whether or not incorrectly labelled blocks should be counted as ward or municipality splits. This has nothing to do with physical contiguity.

The meaning of paragraph 7 is less clear to me. What does it mean to say that the ward fragments are not actually “separated by the territory of another municipality from the major part of the municipality to which it belongs”? What if the ward fragment is separated by another district from the main body of the district to which it belongs?

One thing is clear. The Joint Stipulation does not dispute the actual physical location of any of the census blocks. Using the Census Bureau’s census block GIS file to draw maps defined by the Democratic Senator Respondents’ block assignment files will still result in situations where landbound portions of some districts are unconnected to the rest of the district.

In December 2023, the Wisconsin Supreme Court threw out the existing state legislative maps. If the state legislature and governor cannot agree on new maps, the Court ruled that they would choose a remedial map from among a list of submissions.¹ Those submissions were due to the Supreme Court on January 12, 2024.

The Court’s majority opinion described a set of criteria that they would use to evaluate the maps. However, they did not define specific metrics. Each party submitting a map was free to choose their own metric when arguing why their plan is best. There are many empirically legitimate ways to measure concepts like compactness and partisan balance. The most important thing is that the measures be applied to each plan in exactly the same way. That is what I have done in the analysis below.

To analyze these plans, I have constructed an open source repository of code and data available here. That repository generates the scorecards below, along with many more metrics. For instance, this file includes the results of each presidential, gubernatorial, US senate, attorney general, and state treasurer race in each proposed district from 2012-2022. I encourage interested readers to explore the complete resource for themselves.

Update 1/18: On January 17, the Court rejected the Petering submission because Matthew Petering was not among the original parties to the case.

Assembly

Population Deviation

This measures how well each plan achieved equal populations across districts. It is the range between the most and least populous districts, divided by the ideal district size. Lower numbers are better. The new submissions fall into two camps. The Law Forward, WILL, and Legislative Republican plans each have population deviations close to 1%. The rest of the plans have deviations closer to 2%.

Majority Minority Districts

Federal law requires that, under certain circumstances, districts be drawn where minority voters have the ability to elect candidates of their own choosing. In Wisconsin, that has generally meant 5 districts where Black adults make up a majority and 2 majority Latino districts. All the plans here accomplished that, with the exception of the Senate Democrats plan, which created a sixth majority Black district.

Contiguity

This is one is a simple pass/fail requirement. Every component (census block) of a district must be touching the rest of the district, with the exception of literal physical islands. The old maps were thrown out in December because the Supreme Court chose to interpret the Wisconsin Constitution’s “contiguous territory” requirement literally.

Geographic Splits

It’s impossible to draw contiguous, equal-population districts without splitting counties, municipalities, and wards. But the Court prefers plans to split fewer of them, if possible. Here I measure the number of municipalities, counties, and wards split into multiple districts, which themselves cross into other municipalities or counties. (I don’t count districts which lie entirely within a larger municipality or county).

Across all geographies, the plan submitted by Legislative Republicans has the most splits. WILL’s plan splits the fewest municipalities and counties, but more wards. The Wright Petitioners’ plan splits no wards. These ward split totals do not include splits in wards which the parties agreed not to count in a joint stipulation filed on January 2nd.

Compactness

There are many ways to measure compactness, but they generally show similar rankings. See this table for multiple measures of compactness. In the scorecard below, I show each plan’s average Reock score. The Reock score is the ratio of the district’s area to the area of the smallest circle than can be drawn around the district. A score of 1 equals perfect compactness, so higher numbers are better.

Five of these seven plans have closely clustered Reock scores, between 0.36 and 0.39. The WILL plan achieves an average Reock score of 0.41, and the Petering (FastMap) plan a score of 0.44.

Partisan Balance

The partisan balance of a district could be measured in many ways. Here, I use a statistical model to predict the results of the 2022 state legislative election had they taken place in these proposed districts. I show both the likely number of seats won by each party, as well as the partisan lean of the 50^th seat (determining majority control).

The most Republican-leaning plan is, unsurprisingly, the plan submitted by the Wisconsin Legislature. It creates 35 Democratic seats to 64 Republican seats. Democrats would need to carry the state by 16.3 points (58.15% of the two-party vote) in order to win a majority of the Assembly.

The WILL plan slightly softens this Republican advantage, creating 39 Democratic seats to 60 Republican.

All the other plans are more favorable to the Democrats. The most Democratic-leaning plan is the one submitted by Law Forward, which would create (per my model), 49 Democratic seats to 50 Republican ones. Democrats would need to win the state by 3.3 points (51.65%) in order to win a majority.

Senate

The scores for the Senate maps are generally similar. Recall that each Wisconsin State Senate districts consists of three adjacent Assembly districts.

Notably, the Senate Democrats plan and the Petering (FastMap) plans both create outright Democratic majorities, according to my model of the 2022 election. Of course, only even or odd-numbered elections take place in a given election year. The 2024 State Senate elections will cover only the even-numbered districts. Of those 16 seats, 6 are currently held by Democrats and 10 by Republicans. The Wright plan includes the most Democratic-leaning even-numbered seats (10), followed by the Evers and Law Forward plans (9 each).

Edit: The plan submitted by the Senate Democrats contains 7 Assembly and 2 Senate districts which are not contiguous according to the Census Bureau’s Census Block GIS file. However, a joint stipulation filed by the parties states that the disconnected census blocks should not actually be counted as noncontiguous. I have accordingly edited these scorecards and this blog post to reflect this. I have also removed these blocks from the list of wards splits in all plans, and I have corrected an error in the calculation of Reock Scores.

Edit 1/18: I have added a footnote explaining the Court’s 1/17 decision to exclude the Petering map.

1. If none of the proposed remedial maps satisfy the Court, they may request that their hired consultants draw one as well. ↩︎