Mathematicians apply algorithms to stop forgery


For decades, one of those users was Thomas Hofeller, ”Michelangelo of the modern gerrymander“, Has long been the official director of the Republic National Committee for Redistribution, who died in 2018.

Germanding schemes include “shooting” and “packing” – scattering votes for one party by constituency, reducing their power, and uniting like-minded voters into one constituency, losing the power they would have elsewhere. The city of Austin, Texas is cracked, divided into six counties (it’s the largest city in the U.S. that doesn’t connect the county).

In 2010, the full force of the threat was materialized by the Republican Redistrict Majority Project, or REDMAP. She spent $ 30 million on state-level legislative races, with winning results in Florida, North Carolina, Wisconsin, Michigan and Ohio. “The 2010 victories gave them the power to draw maps for 2011,” says David Daley, author Ratf ** ked: The true story behind the secret plan to steal American democracy.

“What was once dark art is now dark science.”


That technology has advanced by leaps and bounds since the previous redistribution cycle has only outweighed the outcome. “It made the gerrymanders drawn that year so much more durable and resilient than any other gerrymanders in the history of our nation,” he says. “The sophistication of computer software, the speed of computers, the amount of available data allows partisan cartographers to put their maps through 60 or 70 different iterations and to really improve and optimize the partisan performance of those maps. . ”

As Michael Li, a redistribution expert at the Brennan Center for Justice at New York University School of Law, says, “What was once dark art is now dark science.” And when manipulated cards are applied in elections, he says, they are almost impossible to master.

Mathematical microscope

Mattingly and his Duke team they have long been late writing code that they expect to produce a “big win, algorithmically” -prepared for the actual application of their latest tool, which debuted in a paper (currently under review) with a technically intoxicating title “Multi-Scale Merge-Split Mark’s Monte Carlo redistribution chain. ”

Improving technical discourse, however, is not a top priority. Mattingly and his colleagues hope to educate politicians and the public, as well as lawyers, judges, fellow mathematicians, scientists – all who are interested in the cause of democracy. In July, Mattingly gave a public lecture with a more accessible title that shortened: “Can you hear the will of the people in the vote?

Deformed districts are often considered a sign of an attacker. With the 2012 map in North Carolina, congressional districts were “beasts of very strange appearance,” says Mattingly, who (with his key associate Greg Herschlag) gave expert testimony in some of the lawsuits that followed. In the last decade, there have been legal challenges across the country – in Illinois, Maryland, Ohio, Pennsylvania, Wisconsin.

But while such crippled counties “make really nice posters, coffee cups and T-shirts,” Mattingly says, “the truth is that stopping weird geometries won’t stop slipping.” And in fact, with all the technologically sophisticated sleeves, a map that breaks can prove difficult to detect.

These North Carolina County Congress maps illustrate that geometry is not a sure indicator of slippage. Maps of NC 2012, with its bizarre county boundaries, were judged by the courts to be a racial attacker. The replacement, the NC 2016 map, looks quite different and tame compared to that, but was considered an unconstitutional political striker. An analysis by Duke’s Jonathan Mattingly and his team showed that the 2012 and 2016 tickets were politically equivalent in terms of party outcomes. A court-appointed expert drew a map of the NC 2020.


Tools developed simultaneously by numerous mathematical scientists provide what is called the “test of extreme external values.” Each researcher’s approach is somewhat different, but the result is as follows: a map suspected of being made incorrectly is compared to a large collection, or “whole,” of unbiased, neutral maps. Mathematical method in action – based on what is called Markov chains Monte Carlo algorithms—Generates a random sample of maps from the universe of possible maps and reflects the probability that any drawn map will satisfy different policy considerations.

Unit maps are coded to encompass the various principles used to draw districts, taking into account the way in which these principles interact with the geopolitical geometry of the state. Principles (which vary from state to state) include such criteria as keeping districts relatively compact and connected, making them approximately equal in population, and preserving counties, municipalities, and communities with common interests. County maps must comply with the U.S. Constitution and the 1965 Voting Rights Act.

With the release of the 2020 Census Board data, Mattingly and his team will load a dataset, run their algorithm, and generate a collection of typical, nonpartisan county plans for North Carolina. From this large distribution of cards and taking into account historical voting patterns, they will discern criteria that should serve as fences. For example, they will assess the relative likelihood that these cards would yield different election outcomes — say, the number of seats won by Democrats and Republicans — and with what difference: with a 50 to 50 split and given the likely sample vote, it is unlikely that a neutral card would give Republicans 10 seats and Democrats only three (as was the case with that 2012 card).

“We use computational math to figure out what we would expect as outcomes for unbiased maps, and then we can compare it to a particular map,” Mattingly says.

They will publish their findings by mid-September, and then hope that state legislators will pay attention to protective fences. When new district maps are proposed later in the fall, they will analyze the results and engage in the public and political discussions that follow – and if the maps are again suspected to be distorted, there will be more lawsuits in which mathematicians will play a central role again.

“I don’t just want to convince someone that something is wrong,” Mattingly says. “I want to give them a microscope so they can look at the map and understand its properties, and then draw their own conclusions.”

Jonathan Mattingly
Jonathan Mattingly is an applied mathematician at Duke University.


When Mattingly testified in 2017 and 2019, analyzing the next two iterations of North Carolina County maps, the court agreed that the maps in question were overly partisan gerrymanders, discriminating against Democrats. Wes Pegden, a mathematician at Carnegie Mellon University, testified using a similar method in the Pennsylvania case; the court agreed that the card in question discriminated against Republicans.

“The courts have long struggled with the way partisan violence is measured,” Lee said. “But then there seemed to be progress, when court after court erased the maps using some of these new tools.”

When the North Carolina case reached the U.S. Supreme Court in 2019 (along with the Maryland case), mathematician and geneticist Eric Lander, a professor at Harvard and MIT who is now President Biden’s best scientific adviser, briefly remarked that “computer technology has caught up with the problem it has spawned. ”He considered it an extremely extraordinary standard-test that simply asks,“ Which part of the redistribution plans is less extreme than the proposed plan? ”-“ a simple, quantitative mathematical question for which there is right answer. ”

Most judges concluded differently.

“Five judges in the Supreme Court seem to have had a hard time seeing how math and models work,” Lee said. “State and other federal courts have managed to apply this – this was beyond the intellectual capacity of the courts to act, nothing more than a complex case of gender discrimination or a complex case of securities fraud. But five Supreme Court judges said, ‘This is too hard for us.’ ‘

“They also said: ‘This is not for us to fix – this is for the states to fix; This is to fix Congress; it’s not up to us to fix it, “Lee said.

Will it matter?

As Daley sees it, the Supreme Court decision gives state lawmakers “a green light and a speed limit when it comes to the types of partisan attackers they can bring in making maps later this month.” At the same time, he says, “technology has improved to such a place that we can now use it [it] to see through the technological drivers gerrymanders created by legislators. “

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