2. Gerrymandering in Wisconsin
PLSC 111
Discussion Sections
March 19, 2018

3. Background In 2010, Republicans sweep Wisconsin
They win the governor’s office
Majorities in State Senate (19-14) and Assembly (59-40)
Assembly districts are nested in Senate Districts
Therefore total control of government
Act 43, which is the redistricting of the General Assembly is passed and signed by Governor Walker
Goes into effect in 2012 General election (not for recalls)
The current makeup of the Assembly is 63R, 36D

4. Litigation by Democrats
A group of plaintiffs supported by Democrats file a federal lawsuit challenging the Assembly map as a partisan gerrymander
The Supreme Court in three past cases has said that partisan gerrymandering may be impermissible but has never been able to agree on a test to measure it
Legal theory is that the harm is to individuals
Same argument as is made by McDonald and Best
But plaintiffs are using a different measurement of vote dilution
The Efficiency Gap

5. The 2016 Assembly Elections

6. Neutral Mapping Algorithm
Developed by Daniel Magleby and Daniel Moseson
The program uses Census block level data to draw hundreds and thousands of neutral maps across a state
They are then aggregated into districts
Overlaid onto precincts
One can then look at the results of the maps produced to see if a neutral mapping process can produce the results observed

7. The Efficiency Gap Stephanopoulos and McGhee
This looks at “wasted votes”
Lost votes and surplus votes
Seat Margin – (2 × Vote Margin)
To get the efficiency gap number= Sum of column G/Sum of Columns H and I H I A B C D E F G
District
Dem Votes
GOP Votes
Win Party
Lost Dem Votes
Lost GOP Votes
Surplus Dem Votes
Surplus GOP Votes
Wasted Dem Votes (A+C)
Wasted GOP Votes (B+D)
Net Wasted Votes (E-F) 1
16259
16414 R 78
16181 2
11805
10025
890
-9136

8. More on the efficiency gap
The authors say that for state legislative districts, the impermissible level of bias is 8%
It is two seats for Congressional districts
They are not entirely clear why they decided on 8%, but it seems to be related to observations of maps from previous decades
Turnout can effect this
There can also be an issue because more votes are lost than surplus
It can produce false positives and false negatives
In Iowa, it shows the same map to be a Democratic and Republican gerrymander based on what races one looks at

9. Test of McDonald/Best Targets harm to voters rather than parties
Looks at statewide races rather than the seats results for Assembly
Takes away the problems with uncontested seats, incumbency advantage
Comparison of the mean versus the median seat
Differences indicate bias against the voters of one party
Not effected by turnout levels
Concerned with violation of majority rule
Differential Packing

10. Is there a natural gerrymander going in Wisconsin?
The experts hired by the state have alleged that Democratic votes in the state are concentrated in Milwaukee and Madison and thus any map would be biased in favor of Republicans
Note: red and blue are reversed from what we use in this map
Red: Dem
Blue: GOP
Obama win by 7.03% of two party vote

11. Observed Efficiency Gap vs Neutral Maps
President November 2012
Obama v. Romney
Race
Observed
Neutral
2012 Governor Recall
11.84
10.56
2012 President
14.98
2.26
2014 Governor
10.08
9.92

12. Efficiency Gap for Governor Elections
Governor Recall June 2012
Walker v. Barrett
Governor Election November 2014
Walker v. Burke

13. All Elections- Efficiency Gap

14. Application of McDonald/Best
Three elections- Difference in mean-median of the two party share of the vote
2012 Governor Recall (June)
6.36
2012 President (November)
5.21
2014 Governor
5.82
All three show substantial bias in favor of Republicans
We will have data later for other statewide races

15. But under neutral mapping
Neutral mapping decreases the bias levels in favor of Republicans
But still shows some bias
There is a natural bias against Democrats, but not at the levels we observe in the current map
Race
Observed
Neutral
Result
2012 Governor Recall
6.36
2.14
Walker (R) +6.84
2012 President
5.21
3.85
Obama (D) +7.03
2014 Governor
5.82
3.16
Walker (R) +5.74

16. But how much bias President November 2012 Obama v. Romney
We can show that by drawing 992 neutral maps that one cannot generate these levels of bias neutrally
These frequency graphs show the difference between the mean and median in the neutral maps of what is observed
The dashed line is the actual maps currently in place

17. Bias for Governor Elections
Governor Recall June 2012
Walker v. Barrett
Governor Election November 2014
Walker v. Burke

18. Bias- All Races

19. All Elections- Efficiency

20. All Elections- Observed

21. Where does the case stand now?
A three judge panel of the Western District of Wisconsin found this map to be an unconstitutional partisan gerrymander
Set up a three part test
Partisan intent
Partisan effect
No legitimate grounds to explain these
Judge Greisbach dissented and exposed problems with the Efficiency Gap
The case was appealed to the Supreme Court
Oral arguments heard on October 3
Plaintiffs did not defend the EG in Court, and it was skewed by Roberts and Alito
Kennedy was rather quiet
The Court recently decided to take up a Maryland redistricting case this term too

22. This brief

23. Why does this matter?
If the Court rules in a way that overturns either Wisconsin or Maryland, it could overturn many other maps across the country
Pennsylvania map currently under attack in state court
Including all three maps in Indiana
Also, since so many maps are biased, it means in 2018 Dems need to win about 54-55% of the two party vote to win a bare majority in the House

24. In Conclusion
We see that under both of these tests that Democrats are disadvantaged as their votes are weighted unequally due to packing
The McDonald/Best test is a better measure than the efficiency gap
It is consistent in its results
The efficiency gap can show gerrymanders when they may not exist
Or exaggerate their effects

25. Thank You!

26. Writing Assignment Pick Two
1a) Based on the Thursday lecture, where do you think prisoners should be counted for purposes of redistricting where they are incarcerated or where they are from? Why do you choose your option? OR
1b) In Pennsylvania, the State Supreme Court declared the Congressional district lines as violating the PA Constitution. The result of this was that the Court redrew the lines themselves. Do you support or oppose taking away the power of redistricting from legislative bodies and giving them to some other body such as a court or independent/citizen commission? Why or why not?
2) Do you think that the Wisconsin Assembly is gerrymandered in favor of Republicans? Why do you come to the conclusion that you make?