Laquesha Ellis couldn’t figure out why her voter registration could be stricken. The 31-year-old has lived with her two sons in the same gray shingled duplex in a majority black neighborhood for years.

Yet when the Guardian told her her name was one of one in 14 Wisconsin voters at risk of being removed from the voter rolls for potentially having changed addresses, Ellis was surprised. “I still live here. That’s not right,” she said. “Every vote is supposed to count.”

Approximately 232,000 Wisconsin voters are on this list after being identified by a complex matching system. In 2016, Donald Trump won the presidential election in Wisconsin by 22,748 votes, or less than 1%.

A new Guardian analysis has found voters in zip codes that were predominantly black or heavily populated by students were nearly twice as likely to be flagged for removal. These populations are also more likely to vote Democrat.

The Guardian also interviewed 100 people on the list and found that over a third either hadn’t moved at all, or had moved locally. Many were unaware they had to re-register.

“The right to vote could be taken away, regardless of who you are or where you live,” said Megan Gall, national data director for All Voting is Local, an advocacy group. “Eligible voters should never get kicked off the registration rolls.”

The Covid-19 pandemic is adding further complications. Wisconsin and other states are now pushing mail-in balloting rather than voting in person. But if voters are erroneously dropped from the rolls, they might never receive those ballots in the first place.

In 2016, Wisconsin joined the Electronic Registration Information Center (Eric), a multi-state partnership that helps its members keep their voter rolls current by comparing data between government sources such as the post office and Department of Motor Vehicles, to see who might have moved home. A year later, Wisconsin deactivated roughly 308,000 registrations, but eventually, the state reinstated approximately 7,000 voters who were erroneously struck off.

In 2019, the state decided it wouldn’t remove voters from the rolls until 2021, to avoid making the same mistake before this year’s presidential election. Yet in November, the Wisconsin Institute for Law & Liberty (Will), a conservative non-profit law firm, sued the Wisconsin Elections Commission, claiming it violated state law by putting off the cancellations.

The removals have so far continued to be blocked, but Will is asking the Wisconsin supreme court to hear the case before the election.

Will president Rick Esenberg has argued that the process won’t disenfranchise voters because they can register at the polls on election day. But in-person voting may be hampered by the coronavirus outbreak.

“This Will lawsuit says: let’s deactivate these people immediately and get them to register again. But that defeats the whole purpose,” said Reid Magney, a spokesman for the Wisconsin Election Commission. “The more people who have to re-register on election day, the longer the lines are.”

The zip code in Wisconsin where voters had the greatest odds of being put on the list of potential movers was composed entirely of student housing for the University of Wisconsin-Madison. Here, one in four voters, who are likely to vote Democrat, got a mover letter from the state.

“It’s not hard to see why college students – who have notoriously unstable addresses while they are in school, often changing one or more times a year – would be flagged,” said Kenneth Mayer, a political science professor at UW-Madison.

This can lead to confusion. Tommaso Tonelli, a 20-year-old sophomore at the university who was flagged by the Eric system, didn’t know how to update his address. “There are certain places I can go on campus, I’m pretty sure,” he guessed.

Wylie Boelter wasn’t sure why he was on the list. “I mean, I moved to a different place, but still in Madison,” he said.

Having to re-register could prove an obstacle for student voters. Under the state’s current law, students can use a school ID to register to vote only if it meets certain criteria. If they use a student ID, they have to provide additional documentation.

Tammy Patrick, a senior advisor at the Democracy Fund, a nonpartisan organization focused on election administration, said students are stuck in a residency grey area. “They’re often able to register to vote but may not be required to get a driver’s license in that state, meaning they may lack the identification necessary to vote.”

Areas populated by black voters had the second highest rates of voters being flagged for removal, according to the Guardian’s analysis. Twelve percent of voters in majority black zip codes were at risk of removal, compared to 7% of voters statewide. But about a third of the 37 voters interviewed in these areas said they hadn’t moved.

All of these zip codes were in Milwaukee, where African Americans make up nearly 40% of the population. The city plays a critical role in elections: High turnout there helped Barack Obama win the state twice, and low turnout contributed to Trump’s success in 2016, said David Canon, a political science professor at UW-Madison.

Kenneth Dixon, 57, who was also flagged, said he has never moved out of his neighborhood. But he wasn’t surprised that those in his predominantly black Milwaukee zip code, were likely to be on the list.

“So that is how they are trying to win the election for the Republicans?” he said. “Ain’t that a coincidence.”

Kyesha Rembert, whose zip code is 94% black, registered to vote at her cousin’s home, where she has lived for three years after losing her job. Yet her mail is sent to her mom’s address nearby.

When she went to vote in a local election in February, she was told by a poll worker that her name was flagged. Though she was allowed to vote, she was left confused. “I vote in every election, so I don’t know why I’m on the strike list,” she said.

Socioeconomic factors in some of these neighborhoods mean that some residents are more likely to change addresses. Rembert’s zipcode has one of the nation’s highest incarceration rates and two thirds of children live in poverty, the Milwaukee Journal Sentinel reported in 2018.

“You are affecting a population that is already, in some cases, a more vulnerable population on so many levels,” Canon said. “Making them less likely to be able to vote is just not something that should be tolerated.”

While Wisconsin’s method of maintaining voter rolls can be reliable, its margin of error could mean tens of thousands of voter registrations are wrongfully deactivated.

“The timing of this is the critical thing. You don’t want to be doing this in the months leading up to the presidential election,” Canon said. “If you do a purge like this on a big scale, you’re gonna catch 10,000 to 15,000 people that shouldn’t have been removed. ”

Though the state hasn’t deactivated anyone on the list yet, the back-and-forth of the Will lawsuit could still discourage voters.

Zina Noel, a student from a majority black community in Milwaukee, said she has had trouble voting and getting absentee ballots from the state for years. Noel, who is pursuing her PhD, has moved between universities such as Harvard, and technically should be allowed to vote from her permanent address at her parents’ house.

But when she got the letter about losing her registration status, it was the final straw. “It seems fitting that there would be a big purge of voters in mostly Democratic and black areas,” Noel said. “That’s what happens when you live in the black part of Wisconsin.”

She registered instead in Minnesota, where she is living for only few months.