In 1785 the poet Robert Burns wrote a poem called “To a Mouse”, regretting that the natural union between man and mouse had been destroyed by farmers plowing fields, destroying the homes and food sources of mice. The most famous stanza of the poem is the penultimate:
But little mouse, you’re not alone,
In proving foresight may be vain:
The best laid plans of mice and men
Go oft awry,
And leave us only grief and pain,
For promised joy!
I was reminded of this poem this week after the Supreme Court decision on the Voting Rights Act and the ensuing rush to jerrymander voting districts.
Republican talking heads were ecstatic that they could now secure more seats, Democrats were distraught at the perceived consequences. Maybe both were wrong. I want to look at the math, because it might lead us to our own conclusion.
Here we go:
In order to understand how jerrymandering works, let’s use a model system:
• Assume that there are 6 congressional districts
• Assume that there are 100 voters in each district; a total of 600 voters.
Now, let’s assume that there were an equal number of Republicans and Democrats in the area – 300 voters for each party.
In the prior election, the distribution of votes was:
District 1: 80 votes R 20 votes D R wins
District 2: 60 votes R 40 votes D R wins
District 3: 60 votes R 40 votes D R wins
District 4: 40 votes R 60 votes D D wins
District 5: 40 votes R 60 votes D D wins
District 6: 20 votes R 80 votes D D wins
300 votes 300 votes
The votes, split evenly between the two parties, results in 3 district wins for each party.
Now the Republicans want to increase their seats through jerrymandering. How do they do it?
They reset the boundaries of the districts so that the expected votes will be:
District 1: 52 votes R 48 votes D R wins
District 2: 52 votes R 48 votes D R wins
District 3: 52 votes R 48 votes D R wins
District 4: 52 votes R 48 votes D R wins
District 5: 52 votes R 48 votes D R wins
District 6: 40 votes R 60 votes D D wins
300 votes 300 votes
This realignment takes the same 600 votes but splits them in a way to maximize the Republican voters. Now, the votes split so that the Republicans win 5 districts and the Democrats win 1,a pickup of 2 seats.
What about a situation in which the Democrats have a single stronghold in one district?
In this example, we assume that the entire region is more Republican than Democratic, with 330 total votes for R and 270 total votes for D, but that there is an urban area that is solidly D.
District 1: 0 votes R 100 votes D D wins
District 2: 66 votes R 34 votes D R wins
District 3: 66 votes R 34 votes D R wins
District 4: 66 votes R 34 votes D R wins
District 5: 66 votes R 34 votes D R wins
District 6: 66 votes R 34 votes D R wins
330 votes 270 votes
Now, the Republicans redistrict in order to eliminate the Democratic stronghold:
District 1: 55 votes R 45 votes D R wins
District 2: 55 votes R 45 votes D R wins
District 3: 55 votes R 45 votes D R wins
District 4: 55 votes R 45 votes D R wins
District 5: 55 votes R 45 votes D R wins
District 6: 55 votes R 45 votes D R wins
300 votes 300 votes
Now the Republicans win all 6 districts.
These two models are the basic strategies of the redistricting plans. In the first, the natural split in the votes is removed by concentrating D votes in a single district and distributing the other D votes into minority pieces of the remaining 5 districts.
In the second model, the urban concentration of D’s is reversed by diluting their votes by splitting them into other districts.
THE ACHILLES HEEL
There is a potentially fatal error in these stratagems. All of these models are based on previous voting records. They assume that if a voting ward voted R or D in a prior election, that they will vote the same in the next election.
But we also know that the most recent elections have shown an alteration in voter preferences. Districts that had voted overwhelmingly for Mr. Trump in 2024, have elected Democrats to the state legislatures.
In the past 12 months many Red districts have flipped Blue.
In the Virginia House of Delegates, Democrats gained 13 seats in rural areas previously won by Mr. Trump.
The state house seat in Florida including Mar-a-Lago was flipped to a Democrat.
In Texas, a Fort Worth Republican state Senate seat was flipped.
In New York, a Brooklyn state Senate seat saw a 45-point swing to the Democrat
In Iowa, a state Senate seat swung by over 20 points, eliminating the Republican supermajority.
The same happened in Oklahoma, Rhode Island, and New Hampshire.
If your redistricting maps created a slim majority (in example 1, a margin of 52 to 48), and the voters did not follow the prior election models, it only takes a switch of 3 votes, or 6 points to flip that district to the party that you had intended to disadvantage.
With the perceived change in voter preferences showing up in polls nationwide, it is, therefore, possible that by attempting to make more districts Red, by creating more narrow predictive margins in those new districts, the Republican Party is actually creating a situation that is more vulnerable to voters who switch allegiances. The effort to create more Red districts using this strategy may actually result in LESS Red seats due to flipping of districts with small voter majorities.