Jeremy Markovich is a writer in North Carolina.

ASHEVILLE, N.C.—The Gerrymander 5K wasn’t even a 5K. It was a quarter mile too long. It wasn’t timed. There was no exact finish line. The beginning was improvised. “I’ve never done this before,” shouted the starter, “so let’s just do 1-2- 3 go, OK?”

I knew going in the race wasn’t meant to be competitive. It was a publicity gimmick, dreamed up by the League of Women Voters in Asheville, North Carolina, to draw attention to what it considered an egregious example of gerrymandering by Republicans after the 2010 census. The race course, which featured a slightly sadistic series of speed-sucking hills and tight turns, followed the meandering dividing line between North Carolina’s 10th and 11th congressional districts. The route might have been challenging for runners, but it was perfect if you were running a campaign as a Republican.


A little history. Before 2011, the 11th District included all of Asheville, a redoubt of liberalness in an otherwise conservative western end of the state. This made the district one of the most competitive in the South. From 2007 until 2013, it was represented by former NFL quarterback-turned-Blue Dog Democrat Heath Shuler, whose moderate, compromising approach was the only way forward in a decidedly purple district. In 2011, after Republicans won control of both houses of the North Carolina Legislature for the first time since Reconstruction, they got the added bonus of being in control of redistricting after the 2010 Census. They shifted political districts large and small, and North Carolina’s congressional delegation turned from 7-6 advantage for Democrats to today’s 10-3 GOP majority.

A big key was Asheville. To dilute its impact, Republican mapmakers grafted most of the city onto the 10th District, safely held by Republican stalwart Patrick McHenry, and shifted some staunchly Republican counties in the foothills into the 11th. “They cut into McHenry’s vote share,” said Western Carolina University political science professor Chris Cooper, “but not enough to give him competitive elections.” Overnight, the 11th, the most up-for-grabs congressional district in North Carolina, became the most safely Republican. In 2012, with Shuler deciding not to run, Republicans crowded the primary field, and a relatively unknown real estate developer named Mark Meadows won the seat. He went on to co-found and then chair the Freedom Caucus, the group that shut down the government in 2013 over a budget dispute and has battled more moderate, establishment Republicans.

“If this district hadn’t been redrawn,” said Cooper, “there’s still a chance that John Boehner is still Speaker of the House.”

Back to the race. The Gerrymander 5K, as the League of Women Voters envisioned it, was designed to put gerrymandering under the microscope in West Asheville, a hipster enclave of tattoo parlors and biodiesel stations that Thrillist once described as North Carolina’s Brooklyn. The point of the race was to mock the absurdity of the tiny contortions the redistricters had performed to engineer such an obviously self-serving electoral map. Looking at the course, it was easy to see what they were talking about: Much of the line sliced up the neighborhood along main roads, but in two spots it swerved to surgically grab about two dozen homes and pull them into the 11th District.

“It doesn’t really make any sense,” said Alana Pierce, the president of the local League of Women Voters, told me when I asked her about it. She was most perplexed by one place in the line, where it plucks only a handful of houses from the 10th District and puts them in the 11th. “It doesn’t look like one house is strongly partisan Republican or Democrat or anything,” she said. “It’s six houses! It can’t make a difference!”

What I discovered, after running the slowest 5K time of my life, was that those houses actually do make a difference. But it wasn’t the difference the organizers thought. To figure out their significance, I had to do some detective work. The answer I found explains something about modern political mapmaking. It’s not always about what districts look like, or whom they include or exclude, or how they split counties, or neighborhoods. It’s not about whether you think they’re gerrymandered. It’s about whether those lines will hold up in court.



***

As a race, the Gerrymander 5K was unsatisfying. We had to run on the sidewalks; one poor woman nearly decapitated herself when she ran right into the guywire of a telephone pole. Since I knew I wasn’t going have an official time, I tried to pick up some clues as I ran, but with the course’s frequent twists and turns, my brainpower was mostly being used to keep me from getting lost. So, an hour after I finished, I drove back out to the neighborhood in question—a rectangle formed by Louisiana and Majestic avenues and Brucemont Circle—and knocked on the door of every house on the block, six in all.

One was brick veneered and nicely kept, with a pair of Japanese maples in the front yard. Another was a bungalow with a porch crowded with enough gardening debris and junk to gave it a sort of hoarder feng shui. Nobody was home at either one. At what seemed to be a vinyl-sided duplex, a young, skinny, bearded guy came to the door. He’d just moved in and couldn’t tell me much about the neighborhood. Same with a guy at a brand new white two-story. “I’m new,” he said, before saying he still had to unpack. Next door, Aaron Nadler came up to the edge of his chain link fence and filled me in on the neighborhood, called Brucemont. “I’m not sure you’re going to find anything for your story,” he said. I asked him what was the difference between individual houses. “Nothing,” he said. “Nothing.” Nadler is a rare conservative here, and he pointed out where he thought other conservatives lived—mostly, he figured, in the older, slightly shabbier homes owned by older, longtime residents. He also had no idea about the 5K, or the meaning behind the route. “I thought they chose it because I have a bunch of Halloween stuff all over the place,” he said.

Walking the streets, I picked up a lot of subtle details of Brucemont life: The smell of charcoal, the barking dogs, the young kids skateboarding, the older Asian couple waving as they walked. You can see which house has a Honda Accord in the driveway, and which one has a Kia with a Thule bike rack. You can track yard signs for local city council races, but Aaron was right: There was really no major difference between one house or the next. It’s not like a mansion is sitting next to a row of crumbling mill houses. I finished my second tour of the neighborhood no wiser about redistricting than I before I’d laced up my running shoes.

Maybe, I thought, it simply wasn’t possible for a human to spot the differences or patterns. Over the past decade, political mapmaking has turned from an art into a science, backed by reams of data, demographic and political, public and private. Political parties can target individual homes and people beyond voting patterns and party affiliation. Now, they can assign you a number that says how likely you are to vote a certain way based on a myriad of data points, as deep as magazine subscriptions or even whether you own a cat. But it’s unclear if that data filters its way into the maps. In August, North Carolina lawmakers released the raw data used to redraw their highly contentious General Assembly districts, and they stuck mostly to vote totals in presidential, U.S. Senate, and state-level races.

Still, maybe the computer had become sentient. I’d had a theory that this little notch in the map might be completely computer generated and therefore unexplainable—in the way that an engineer at Facebook wouldn’t be able to tell you exactly why your News Feed displayed the exact stories it did in a specific order. But Jane Pinsky, with the Coalition for Lobbying and Government Reform in Raleigh, told me the machines have not taken over completely. A human definitely drew that line, she contended, and there’s a definite reason why it’s there. She also gave me a helpful piece of information. Nearly every state in the country uses the same program to draw its districting lines. It’s called Maptitude. And it’s really expensive.

Pinsky suggested I mess around with a free open-source facsimile of Maptitude named, nerdily, Dave’s Redistricting. It’s like SimCity for politically motivated geography geeks. So I started creating my own makeshift 11th District, watching the numbers change with every new chunk I added. I understood the nuance: A box showed, in real time, whether the district was becoming more red or more blue with every click. But it still didn’t tell me anything specific, and I couldn’t get down to house level, anyway.

I stumbled across more clues, but they, too, didn’t get me any closer to an answer. The dividing line followed the edges of precincts through West Asheville, and split only one of them, Precinct 14.2, where Brucemont lies. But shifting individual houses into Meadows’ district didn’t seem to help him very much. In fact, of the mere 12 votes cast there in the 2016 general election, 10 went to Meadows’ Democratic opponent. The reason for this tiny tweak, then, wasn’t overtly political.

Things made sense after I called a guy named Blake Esselstyn. Until 2015, Esselstyn was the GIS director in Asheville’s planning department, meaning he’d looked at complex data-rich maps of the city nearly every day for more than a decade. Recently, he’d left to go into the private sector, but became obsessed with political districts, started blogging, and attended redistricting conferences. There was a simple explanation, he said, and it had nothing to do with what sort of people lived in which house, but how many.



***

Up until the 1960s, some states almost never touched their political boundaries, despite the fact that population growth and shifts to urban areas made their populations wildly unequal. The U.S. Supreme Court’s landmark decision in Baker v. Carr in 1962 allowed the court to have a role in declaring whether legislative districts were constitutional. Two years later, the court decreed in Wesberry v. Sanders that states should draw congressional districts to make them nearly identical in population, and a slew of cases afterward held that each district in a state should have as equal a population as possible, to hew to the concept of “one person, one vote.”

With modern mapping, it’s now possible to make districts not just close to equal, but exactly equal. In North Carolina, nine of the 13 districts have a population of 733,499, according to the 2010 census. The other four each had one fewer person. Court decisions have shown that if districts’ populations are not equal, a state has to have a compelling reason why. Thus, many states, including California, Connecticut, Florida and Indiana, drew congressional districts with the exact same number of people in them statewide. By making each district’s population precisely the same, a mapmaker takes that argument out of a legal challenger’s arsenal.

What’s another way to make districts more court-friendly and lawsuit proof? By following county lines, whenever possible. North Carolina has 13 congressional districts, but splits just 12 out of 100 counties. Most of those splits are in urban areas. Activists say the same vote-splitting that’s at work in Asheville is also at work in other Democratic neighborhoods in places like Fayetteville and Greensboro. In those places, the density also makes it easier to subtly weave in and out of neighborhoods, methodically tweaking until you get the population exact, and your work is unable to be seen until you zoom in. That’s what Esselstyn thinks was at work in Brucemont. If all of West Asheville is blue, it doesn’t matter exactly where you zig or zag, so long as you get the population equal on both sides. “It is a fair amount of trial and error,” he says. At some point, the mapmaker needed to shift 12 people from one district to the other. He found them along Louisiana Avenue in West Asheville.

There was only one man who could, with absolute certainty, confirm all of this: Tom Hofeller, the prolific Republican mapmaker who drew the last two sets of North Carolina’s maps and created that line. He picked up the phone at his home in Raleigh, and we had an amiable chat for more than an hour, but he refused to go on the record for any of it, citing pending lawsuits over redistricting. Other than depositions, he’s spoken on the record at length only for a 2012 profile in the Atlantic, where he mentioned that political maps that aggressively tilted the landscape in one party’s direction, like Texas’, could get tossed out in federal court.

So, out of all of the answers, the equal population explanation is both the most likely and the most boring. And that, really, is the point.

To paraphrase the late Supreme Court Justice Potter Stewart, most people consider gerrymandering to be like pornography: They know it when they see it. In North Carolina, it used to be easy to see. A Democrat-controlled state Legislature created the 12th District in 1992 as a majority-minority district to satisfy the Voting Rights Act. In order to get enough black voters, the district followed interstates and back roads from Gastonia to Durham, branching off to grab African-Americans in Charlotte, Winston-Salem, and Greensboro. In some spots, it was only as wide as a lane on I-85. The move worked. Democrat Mel Watt, an African-American, easily won election in 1992 and had no serious challenger until he resigned in 2014 to take a position in the Obama administration.

The old 12th District was held up as a textbook case of egregious racial gerrymandering, and its shape and makeup went before the U.S. Supreme Court five times. In May, justices said that the district was unconstitutional because it packed too many black voters into it, but by then, it had been redrawn by Hofeller in 2016 to satisfy a lower court decision. It now fits inside the most Democratic section of North Carolina’s most populous county, Mecklenburg, where whites hold a slight majority now. The partisan effect is the same statewide: The packing of Democratic-leaning voters into the 12th makes the surrounding districts safer for Republicans.

(The redrawing of the 12th district in 2016 did have a ripple effect on the dividing line in West Asheville. To keep the official population in each district at 733,498 or 733,499, the line moved from a point farther west to its current location, which could be more proof that the overall intent wasn’t to split the neighborhood’s votes in half, but rather to put just enough of Democratic Asheville into the hyper-Republican 10th District to keep the 11th safely Republican as well.)

The 10th and 11th districts are overwhelmingly white and thus haven’t been challenged on racial grounds, which the Voting Rights Act makes easier to strike down. Lawsuits claim they’re a partisan gerrymander, and many North Carolina lawyers are eagerly awaiting the Supreme Court’s upcoming decision in a Wisconsin case, Gill v. Whitford, to see whether new rules on political data will be put into place. But so far, challenges to the 11th District haven’t gone anywhere, said Pinsky, whose group has filed lawsuits over many state and federal boundaries. “The only route we’ve had to play this out in North Carolina is racial,” she said.

On a broader scale, the move that shifted Asheville into a new district hasn’t gotten much national attention. When zoomed out, the district doesn’t look nearly as contorted as others, has held up legally, and all but guarantees a GOP winner. If you’re a Republican mapmaker, you couldn’t have done a better job.

At the post-race gathering, the author David Daley, who’d run the race and was selling his book on gerrymandering at $20 a pop, jumped onto a bench to speak to the runners, who were, by now, drinking beer. “This is one of the most gerrymandered districts in the country,” he shouted to a crowd of more than 300.

But it’s hard to say, legally, what gerrymandering even is, because judicial decisions are constantly shifting the rules. One Republican consultant told me that when a judge tosses out one set of data, like race, it’s possible to use different data to get the same outcome, and indeed, when North Carolina lawmakers redrew districts in 2016 to comply with a court order, the result was largely the same. An Associated Press analysis in June still found the maps to be among the most Republican-skewed in the country.

Yes, both sides do it. In our current climate of whataboutism, Republicans can point the finger back at, say, Democrats in Maryland, who are fighting off gerrymandering claims in that state. And yes, mischief in mapmaking has been around for as long as we’ve been drawing districts. It’s just now that technology is far better than ever, and people are quick to blame gerrymandering for our current polarized state.

“It still doesn’t change the United States Senate, it still doesn’t change governors’ mansions,” said Cooper. “It is a piece of this larger puzzle of American politics. And I worry, sometimes, a little bit, that people are beginning to think that it’s the biggest piece, or if it’s the one piece that we fix, that everything else will fall into line. I don’t know that that’s the case.”

There is a case to be made that gerrymandering is getting more sophisticated and harder to spot with the naked eye, even from the course of a 5K race. You might know something is wrong, but be unable to explain it, even though the proof is there, hiding in plain sight. “It doesn’t look bad,” said Pinsky, “unless you know what they’ve done.”