MADISON - A conservative group is seeking to quickly remove thousands of people from the voting rolls who election officials believe may have moved.

The question over how to treat as many as 234,000 voters comes as Wisconsin emerges as one of the most heavily contested states in next year's presidential election.

The Wisconsin Election Commission last week sent letters to voters who it believes may have moved. The letters told the recipients to update their voter registrations with their new addresses if they have moved or to notify the commission if they have not moved.

If the voters do not act, their voter registrations will be suspended after April 2021, according to the commission.

Three Wisconsin residents represented by the Wisconsin Institute for Law & Liberty filed a complaint with the commission Wednesday demanding that the commission suspend the registrations of voters who do not respond to the letters by next month.

If the commission does not change course, the voters bringing the complaint will likely sue over the issue, said one of their attorneys, Anthony LoCoco.

"It's important to have accurate voter rolls," LoCoco said. "Part of maintaining accurate voting rolls is making sure people are registered to vote at the proper place."

The state generated the list of voters who have possibly moved with the assistance of the Electronic Registration Information Center, or ERIC, which helps 29 states keep their voting rolls accurate. The center gathers information from other sources, such as the U.S. Postal Service, to detect when someone has moved.

The complaint argues that state law requires the commission to remove people from the voter rolls within 30 days if it does not get responses after notifying them it has reliable information they have moved.

The commission's executive director, Meagan Wolfe, disputed the complaint's claim that the commission must remove voters from the rolls within 30 days of sending them a letter based on data from ERIC.

"I think it's really important to note that the ERIC process, there are no statutes that govern that process as far as how that (voter) list maintenance happens," Wolfe told reporters. "State law requires that the State of Wisconsin join ERIC, but it does not specify how this maintenance is conducted."

In a statement issued later in the day, Wolfe said the commission would discuss the issue at a Dec. 2 meeting.

"The commission is confident that it is complying with Wisconsin law," she said in her statement.

Commissioners have been reluctant to suspend people from the voter rolls as quickly as those who filed the complaint want because thousands of voters contended in 2017 they were improperly removed from the rolls when similar mailings were sent that year.

The purpose of the mailing is to make sure the state's voter rolls are as up-to-date as possible.

In addition to identifying people who have moved, the commission encourages people to register to vote. For instance, last year it sent postcards to 384,000 people who were eligible to vote but had not registered.

In 2017, the commission contacted about 340,000 voters who it believed might have moved. It removed many of them from the voter rolls because they did not respond.

But election officials in the months afterward determined many of the people were contacted because of faulty data.

In September 2018, the commission told local election clerks they could reinstate voter registrations if they believed people had been wrongly removed from the rolls. That cleared the way for Milwaukee to restore the registrations of about 21,000 voters — nearly half of the 44,000 Milwaukee voters who had been taken off the rolls in 2017.

To avoid similar problems, the commission in June voted unanimously to give people more than a year to respond to the latest mailings before they would have their voter registrations suspended.

The commission ordinarily consists of three Republicans and three Democrats. It has one Republican vacancy at the moment.

Voters who are removed from the voter rolls can re-register online, in a clerk's office or at the polls. Fights over voting rolls have been more intense in other states, particularly those that do not allow voters to register on election day, as Wisconsin does.

Analiese Eicher, executive director of the liberal One Wisconsin Now, accused the Wisconsin Institute for Law & Liberty of trying to give Republicans an advantage in next year's elections with a "back-door voter roll purge."

Contact Patrick Marley at patrick.marley@jrn.com. Follow him on Twitter at @patrickdmarley.