When the election of the liberal justice Janet Protasiewicz flipped the balance of the Wisconsin Supreme Court in 2023, liberal groups responded immediately. A lawsuit was filed the day after she joined the court, which led to the new liberal majority barring further use of the existing state assembly and senate districts. Those maps had been crafted by Republican legislators and redounded greatly to their benefit. In 2022, the Democratic Governor Tony Evers won reelection with 51.1% of the vote, yet he only carried a majority in 39 of 99 Assembly and 13 of 33 Senate seats.

For fear of the Court imposing an even worse map (for them), Republican legislators responded by passing a map drawn by Evers. Evers accepted this compromise; although it was opposed by almost all state legislators from his own party. The results of this new map were on full display in November 2024. Harris lost the state with 48.7% of the vote, but she still carried a majority of the vote in 49 of 99 assembly seats and 17 of 33 senate seats.

Throughout all of this, the 8 Wisconsin congressional districts remained unchanged. In fact, the congressional map used in 2022 was barely different from the one drawn in 2011.

Spring 2025 once again saw the ideological balance of the Supreme Court at stake. This time, a victory by the conservative candidate would have flipped the majority back to its pre-2023 status quo. Instead, the liberal candidate Susan Crawford won by 10 points, and liberal groups again responded by promptly filing redistricting lawsuits, this time challenging the Congressional map.

To date, two petitions and one complaint (from different prominent firms) have been filed, each making quite different arguments as to why the state courts should toss the current map. The first two petitions were filed directly with the State Supreme Court. Although the court agreed to hear opposing and supporting briefs to the petitions, they ultimately declined to hear them in late June, issuing no comment about the merits of the arguments presented. The third complaint was filed with the Dane County circuit court shortly after the first two were rejected. For reasons I’ll discuss below, this latest case makes arguments which may bear more fruit for those seeking new maps.

You might think that adding up the results of a statewide April election in legislative districts should be simple, but it’s not.

First problem: the state currently doesn’t include political district numbers in the results for nonpartisan elections.

Second problem: votes in Wisconsin are counted, not in wards, but in combinations of wards called “reporting units,” and April nonpartisan elections can use different reporting units than in November elections.

Third problem: the reporting units used in April sometimes straddle partisan district lines.

So, my media consumer advisory is this; if you read an article telling you the results of an April election apportioned into legislative districts, you should expect to see an explanation of how the author obtained that data.

Here is how I do it. First, I identify the individual wards comprising each reporting unit. Then, I match those wards to the most recent GIS ward file I can find.[1] Every ward falls within a single political district, so I check to be sure that each ward in every reporting unit is assigned to the same district. If a reporting unit is split across multiple districts, I divide its vote according to the proportion of the reporting unit’s registered voters residing within each district.[2]

Here are the results of the 2025 April Supreme Court election between the Republican-endorsed candidate Brad Schimel and the Democratic-endorsed candidate Susan Crawford.

Crawford won 55.0% of the vote. Under the maps as currently used, this worked out to 54.5% of Assembly districts (54/99), 57.6% of Senate districts (19/33), and 50% of Congressional districts (4/8).

Table 1: Results of the 2025 Wisconsin Supreme Court Election in legislative districts

The next table compares those results with some of the other recent redistricting plans, either proposed or used. Under the GOP-drawn maps used in the 2022 election, Crawford’s 10-point net victory would’ve resulted in 5-seat Republican majority in the Assembly and a 3-seat Republican majority in the Senate.

Table 2: Results of the 2025 Wisconsin Supreme Court Election in select alternative legislative districts

Implications for 2026

Wisconsin’s state legislative maps now closely reflect the results at the top of the ticket. Both Donald Trump and Tammy Baldwin translated their narrow 1-point victories into 1-seat majorities of assembly districts. But actual Republican assembly candidates won a 5-seat majority.

In previous analyses, I found that incumbency advantage was worth about 4 points (net) for Republican Assembly candidates in both 2024 and 2022. This advantage means that the Republican Assembly majority can likely withstand election years resulting in a narrow statewide victory for Democrats. But anything approaching Crawford’s landslide victory puts many Republican incumbents in competitive districts much more at risk.

Here are the 6 closest battleground seats in the State Assembly. They are all seats which split their vote between the Assembly and presidential races. Five of them voted for Harris and a Republican legislator, while one voted for Trump and a Democratic legislator. In all instances, Susan Crawford defeated Schimel by double-digits.

Table 3: Election Results in Key Battleground Districts of the Wisconsin State Assembly

Likewise, there are 4 battleground State Senate districts, one of which (the 31st) is currently represented by a Democrat and the rest by Republicans. Because Wisconsin elects odd-numbered senate districts during midterm years, these seats will hold their first elections under the new boundaries in 2026. As in the Assembly battlegrounds, Crawford won each of these districts by more than her statewide margin of victory.

Table 4: Election Results in Key Battleground Districts of the Wisconsin State Senate

[1] I begin with the most recent LTSB stateward ward boundary file (Jan. 2025 in this case). When recent annexations or incorporations make these boundaries already out-of-date, I obtain updated boundaries from the county. For the April 2025 election, I needed updated ward boundary files from Dane and Waukesha counties.

[2] I do this using a geocoded copy of the state’s voter file, but it could also be done using the state’s monthly ward-level registered voter report.