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Gerrymandering:

How Redistricting is Reshaping democracy

Fellow of The Institute for Mathematics and Democracy

Wellesley College Department of Mathematics

Cianna Salvatora

December 5th, 2024

Redesigning Our Democracy:

A Quantitative Approach

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TABLE OF CONTENTS

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Gerrymandering’s Effect on Competitiveness

Solutions

Legal & Legislative Battles Over Gerrymandering

What is Gerrymandering?

How Gerrymandering is Measured

How Gerrymandering Works

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What is Gerrymandering?

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Definition & Purpose

Gerrymandering: When district boundaries are manipulated intentionally to favor one political party or group.

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Brief History

Gerry

Salamander

+

=

Gerrymander

Origins: The term “gerrymandering” combines salamander and the name of Elbridge Gerry, the Massachusetts governor in 1812, whose redistricting plan resembled a salamander.

Early Use: Though used since the early days of American politics, gerrymandering became more widespread after universal male suffrage was ratified in post-Civil War.

Fluctuating Use: Its prevalence has varied as states employed different tactics to suppress voter influence.

Modern Resurgence: With the increase in computer technology, gerrymandering has become more precise and widespread, reshaping elections more effectively.

https://www.britannica.com/biography/Elbridge-Gerry

https://www.britannica.com/topic/gerrymandering

https://www.google.com/url?sa=i&url=https%3A%2F%2Fwww.smithsonianmag.com%2Fhistory%2Fwhere-did-term-gerrymander-come-180964118%2F&psig=AOvVaw0hbkwK1e7UkslPTWnsKcy7&ust=1697489071013000&source=images&cd=vfe&opi=89978449&ved=0CBAQjRxqFwoTCOD79dr1-IEDFQAAAAAdAAAAABAE

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Types of Gerrymandering

Partisan Gerrymandering

Distorting districts to favor one political party over another

Racial Gerrymandering

Targeting or diluting minority voting blocs, to limit their political influence

In both forms of gerrymandering, politicians manipulate district boundaries to control the makeup of their electorate, effectively “picking” the voters in their favor.

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How Gerrymandering Works

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Core Techniques

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Packing and Cracking

Packing: Concentrating the opposition’s voters into a small number of districts, limiting their influence in the broader election.

Cracking: Diluting the opposing party’s power by spreading their voters across multiple districts, ensuring they don’t form a majority in any of them.

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Computer Modeling

A Science of Manipulation:

Gerrymandering has evolved into a precise science with the rise of computer algorithms and advanced data modeling.

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Gerrymandering’s Effect on Competitiveness

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Impact on Competitiveness

This map highlights states where gerrymandering has created imbalances in representation, affecting the competitiveness of elections. The analysis comes from the Brennan Center for Justice, a program at New York University School of Law, which studied redistricting patterns after the 2020 census.

Gerrymandering impacts competitiveness by creating districts that strongly favor one party, reducing the likelihood of competitive races. This cycle, the overall map bias favors Republicans, with an estimated 16-seat advantage in the U.S. House compared to fair maps. This advantage is primarily attributed to redistricting in GOP-controlled states, especially in the South and Midwest.

Understanding these patterns is key to assessing the broader impact of gerrymandering on fair and competitive elections.

https://www.brennancenter.org/our-work/research-reports/how-gerrymandering-tilts-2024-race-house

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The Competitiveness Problem

Here we see a summary of the competitiveness ratings for the 2024 House races. Out of 435 total seats, only 22 districts are considered true toss-ups, meaning only about 5% of seats are genuinely competitive. The rest are categorized as solid or likely for either Democrats or Republicans, making most races non-competitive.

This lack of competition isn’t new. Over the past few decades, we’ve seen a dramatic decline in the number of competitive districts. Historically, incumbents have a reelection rate above 90%, which means most elections are decided long before voters cast their ballots.

Why is this a problem? Fewer competitive races lead to less accountability–politicians in safe districts don’t need to appeal to a broad range of voters. Instead, they focus on the interests of their party’s base. This contributes to polarization and reduces incentives to work across the aisle to compromise.

In short, competitive districts are essential for a healthy democracy because they force candidates to propose policies that appeal to more people, not just their core supporters. Without competitive districts, our political system becomes more divided and less responsive to the needs of all voters.

Refer to Leah’s talk

https://gai.georgetown.edu/the-houses-competitiveness-problem-or-lack-thereof/

https://www.cookpolitical.com/ratings/house-race-ratings

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Some Funky Districts

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How gerrymandering is Measured

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Measuring Gerrymandering

Efficiency Gap

Measures the difference in wasted votes between parties
Highlights partisan imbalances caused by district manipulation

Compactness Scores

Analyzes district shapes to detect irregularities.
Common Methods: Polsby-Popper, Reock, and Schwartzberg scores

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Quantifying Gerrymandering

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Legal & legislative battles over gerrymandering

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Recent Court Rulings

Supreme Court’s Stance:

Right-leaning Supreme Court has been dismissive

Rucho v. Common Cause (2018)

Notable Cases:

Alexander v. South Carolina State Conference of the NAACP (2023)

Allen v. Milligan (2023)

Supreme Court's Stance:

The right-leaning Supreme Court has generally been dismissive of gerrymandering cases, particularly those involving partisan bias.
Rucho v. Common Cause (2018): The Court ruled that federal courts cannot review partisan gerrymandering claims, leaving these decisions to state legislatures. Despite acknowledging that partisan gerrymandering may be "incompatible with democratic principles," the Court deemed it a political issue outside its jurisdiction (5-4 ruling, ideologically split).

Notable Cases:

Alexander v. South Carolina State Conference of the NAACP (2023): The Supreme Court heard a case about whether South Carolina's legislature intentionally removed Black voters from the 1st Congressional District to benefit Republicans. This case highlighted the growing use of computer models in gerrymandering litigation.
Allen v. Milligan (2023): The Supreme Court ruled that Alabama’s district map likely violated the Voting Rights Act by diluting Black voting power. Alabama was ordered to create a second Black-majority district (5-4 decision).

https://www.google.com/url?sa=i&url=https%3A%2F%2Fwww.politico.com%2Fnews%2F2023%2F07%2F20%2Fsupreme-court-ethics-congress-00107413&psig=AOvVaw0DXqGsoIqVUkc_-7EgSXe7&ust=1697489188001000&source=images&cd=vfe&opi=89978449&ved=0CBAQjRxqFwoTCKDlhJf2-IEDFQAAAAAdAAAAABAE

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Freedom to Vote Act

Ban on Mid-Decade Redistricting: only redistrict every 10 years after the census

Redistricting Criteria:

Constitutional and Voting Rights Act compliance
Protect minority voting power
Preserve communities of interest

Prohibition on Partisan Favoritism: states can not favor one party over another

So, under the Freedom to Vote Act, there would be a ban on mid-decade redistricting—this means redistricting can only happen following the decennial census or through a court order, ensuring a more stable electoral process.

The redistricting criteria focus on three main points:

Constitutional and Voting Rights Act compliance, ensuring districts don’t violate these protections.
Protecting minority voting power, so that communities aren't unfairly diluted.
Preserving communities of interest, which refers to maintaining the integrity of groups that share common social, economic, or cultural characteristics.

Additionally, the Act enforces a prohibition on partisan favoritism. Essentially, states cannot manipulate redistricting to favor one political party over another. To prevent this, the process will be evaluated using computer models, statistical analysis, and public input, to ensure fairness and transparency."

https://www.brennancenter.org/our-work/research-reports/how-gerrymandering-tilts-2024-race-house

https://www.congress.gov/bill/117th-congress/senate-bill/2747/text#toc-H0C8D137F86DA4B8B9EDFCE0E97424BA3

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Impact of Inaction

Filibuster Blocked the Freedom to Vote Act in the Senate
Continued partisan gerrymandering and vulnerability of voting districts
Disenfranchisement of minority voters, especially in states with restrictive laws
Gridlock in Washington preventing meaningful electoral reform
Undermining public trust in our democracy

Partisan Gerrymandering

Voter Suppression

Gridlock in Washington

While the Freedom to Vote Act was a significant step towards electoral reform, it was not passed, due to a filibuster in the Senate. This has had considerable consequences, such as the continued vulnerability of voting districts to partisan gerrymandering, with states having more leeway to manipulate district lines to favor one party. Moreover, the failure to pass this bill means continued disenfranchisement of minority voters, particularly in states with restrictive voter ID laws and policies that disproportionately affect communities of color.

The impact of inaction goes beyond just one bill. It reflects a larger trend of gridlock in Washington, preventing meaningful change on key issues like voting rights, and ultimately, undermines public trust in our democracy. Without reforms like those proposed in the bill, voter suppression tactics remain unchecked, and many Americans continue to face significant barriers to participating in our political process.

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Solutions

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Independent Redistricting Commissions

Independent Redistricting Commissions (IRCs) remove politicians from the redistricting process.

Goals:

Fair representation
Transparent and impartial redistricting
Public input and oversight.

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Michigan’s Redistricting Reform

Old map favored incumbents and specific parties. New map prioritizes fairness and voter input.

Old District Map (Before IRC)

New District Map (After IRC)

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Multi-Member Districts

Single-Member Districts

Multi-Member Districts

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THANKS!

Do you have any questions?

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