In a legal settlement being hailed by conservatives, Ohio will officially sign on to a controversial inter-state program to combat voter fraud. Voting-rights groups fear the program could make it easier for valid voters to be wrongly purged from the rolls. And that’s not the only cause for concern in the deal.

The news comes as the nation’s most pivotal swing state prepares to pass a new round of voting restrictions.

In the deal announced Monday, Ohio agreed to participate in the Interstate Voter Registration Cross-Check program, known as Cross-Check, run by Kansas’ Republican Secretary of State Kris Kobach, which aims to identify voters registered in more than one state. Ohio had been sued in federal court by two conservative groups—True the Vote, the Tea Party-linked group that stokes concern over voter fraud, and Judicial Watch—seeking to force the state to clean up its voter rolls.

“Dirty election rolls can lead to voter and election fraud,” True the Vote said in a press release touting the deal.

But voting-rights advocates say Cross-Check makes it too easy to wrongly remove voters from the rolls. Speaking to msnbc last month, Keesha Gaskins, at the time a senior counsel at the Brennan Center, called Kobach’s program “more of a purge mechanism.”

“It’s a really inefficient system,” said State Sen. Nina Turner, a Democrat and frequent msnbc contributor who is running for secretary of state this year. “It produces a lot of false positives, so it’s very easy to throw somebody off the rolls who is legitimately eligible to vote.”

Under Secretary of State Jon Husted, Ohio has already been officially participating in Cross-Check. Husted, a Republican, said in May that 20 people who may have voted in both Ohio and another state had been flagged via the program, and referred to prosecutors. And just last month, Ohio Republicans passed legislation aimed at making it easier for Husted to cross-reference voter rolls with out-of-state databases.

In that sense, said Matthew McClellan, a spokesman for Husted, Monday’s agreement merely codifies what the state was already doing.

But the deal, which runs through the 2018 election, nonetheless gives Buckeye State conservatives an additional tool to push for aggressive culling of voter tools in advance of the 2014 and 2016 elections. And it makes it harder or impossible for a future secretary of state—most likely Turner—to withdraw from Cross-Check while the agreement is in effect.

Kobach, who has spearheaded Cross-Check, is a former GOP operative who has made stopping voter fraud and non-citizen voting a centerpiece of his time in office in Kansas. The program lets officials in the 26 participating states—most of them GOP-controlled—compare voter rolls and remove people who are registered in one more than one place.

Everyone agrees on the need to clean up voter rolls, which typically are riddled with errors. A competing inter-state system, devised by the Pew Charitable Trusts and known as ERIC, has won widespread praise for accuracy and reliability.

One problem with Cross-Check’s approach is that voters who register after moving from another state are often left on the rolls in the state they left, meaning they might then be struck from the rolls in their new home state after being flagged by Cross-Check. That’s what happened to Ebony Wright, who moved from South Carolina to Virginia several years ago, and was wrongly struck from the rolls last fall after being flagged by Cross-Check, she told msnbc in November.

Wright ultimately straightened things out with her local election board, but she was far from the only false match. One local Republican election official, Lawrence Haake III of Chesterfield County, told msnbc he was told by the state to strike around 2,200 names from the rolls because they’d been flagged by Cross-Check as double-registered. But Haake said when he tested 1,000 of the names, he found that 174—over 17%–had registered in Virginia more recently than any other state, making them valid Virginia voters.

Of course, much depends on what states and counties do with the information Cross-Check provides. Many appear to have used it more carefully than Virginia, whose flawed purge came just weeks before last fall’s election.

True the Vote, an offshoot of a Houston-based Tea Party group, has forged a reputation as a zealous pursuer of voter fraud, despite little evidence that large-scale fraud exists. At the August 2012 meeting where the Ohio lawsuit was announced, a True the Vote official said the group planned to place poll watchers at thousands of polling sites around the country, likening the intended effect on voters to the feeling of “driving and seeing the police following you.”

Turner said the use of Cross-Check isn’t the only worrying aspect of Monday’s settlement. It also requires the state to send confirmation letters annually to people who haven’t voted for two years, to check that they still live where they’re registered. That’s likely to increase the number of voters flagged as “inactive,” meaning they wouldn’t receive election information like mailings and absentee ballots, which act as a spur to voting. The deal also doesn’t do enough to bring new voters into the system, she said.

The settlement comes as Ohio Republicans appear poised to green-light a wave of new voting restrictions in the Buckeye State. Bills to reduce early voting, to end same-day voter registration, and to make it harder to cast an absentee ballot are all likely to be approved in the coming weeks. And late last year, Ohio passed a law that reduced the number of voting machines that counties must have on hand for Election Day. Taken together, the measures could be a recipe for longer lines on Election Day.

A voter ID bill is said to be in the works, though it has not yet been introduced and could face a tough road.

An exhaustive investigation by Husted’s office last year found 135 possible cases of voter fraud—or 0.002% of the 5.63 million votes cast—in the state in 2012. Almost none have led to convictions.

As part of Monday’s settlement, Ohio also agreed to take several other mostly non-controversial steps to keep voter rolls accurate. Those include using federal sources to collect out-of-state death notices in order to remove dead people from the rolls; using Bureau of Motor Vehicle data to update voter registrations with address changes; and encouraging voters to use online tools to keep their records updated.