When Wayne Fish, who lives in Lawrence, Kansas, went to renew his driver’s license in August 2014, the clerk at the DMV asked him if he’d like to register to vote. Fish, 36, had never registered before, but he was concerned about recent cuts to the state’s education budget, so he said yes.

But not long after, Fish was told by his county election office that he’d never been added to the voter rolls, because he hadn’t provided proof of citizenship when he registered —even though he wasn’t asked for it. Fish has no passport, and he was born on a military base that closed decades ago, so he doesn’t know how to locate his birth certificate. As a result, Fish couldn’t vote that fall — and he still isn’t registered.

Now, Fish is the lead plaintiff in a lawsuit filed Thursday by the American Civil Liberties Union that challenges the strict voter registration practices imposed by Kansas’ Republican secretary of state, Kris Kobach. It’s the latest development in an escalating fight over voter registration that also has ensnared a federal election agency and two other Republican-led states.

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The new lawsuit claims that Kansas’ policy of requiring people who register to vote at the DMV to provide proof of citizenship violates federal voting law. More than 30,000 would-be voters have been kept off the rolls as a result of the policy, it alleges. It also seeks to stop Kansas’ plans to trash more than 35,000 registration applications that have been placed on a “suspense list” because they don’t include proof of citizenship.

“What’s happening in Kansas is outrageous,” said Dale Ho, director of the ACLU’s Voting Rights Project. “Thousands of Kansans, including military veterans who have valiantly served our country, are blocked from voting by unnecessary bureaucratic roadblocks imposed by state officials. These shameful actions have made Kansas an epicenter of voter suppression.”

Around 14 percent of all Kansans who have tried to register to vote since the state’s proof of citizenship law went into effect in 2013 have been stymied, the suit claims. It says the law has had a “devastating effect” on voter registration in the state.

“The claim that thousands of potential voters have been blocked from registering as a result of the Kansas proof of citizenship law is entirely false,” Kobach said in a statement. “Kansas’s law, which was passed by a large majority, ensures that every person who registers to vote is a United States citizen. This law has prevented numerous aliens from registering, and that ensures the integrity of our voter rolls.”

The suit is part of a sprawling legal battle between Kansas and voting rights advocates over the state’s efforts to enforce its 2011 voter registration proof-of-citizenship law. Earlier this month, the ACLU and other groups sued the new director of the Election Assistance Commission, the federal agency that helps states run their elections, after he unilaterally granted Kobach’s request to add the proof of citizenship requirement to the instructions for Kansas, Georgia, and Alabama accompanying the federal voter registration form. Kobach’s past attempts to have the form changed were rejected by the EAC and by a federal court.

On Wednesday, the plaintiffs in that lawsuit filed a new motion asking a judge to immediately block the move by the EAC director, Brian Newby, who as a county election administrator in Kansas had a cozy relationship with Kobach.

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The EAC hasn’t responded to the suit against it. A spokesman said Wednesday that the agency had yet to receive it.

In yet another lawsuit, last month a court struck down Kobach’s effort to divide his state’s voters into two groups — one composed of those who provided proof of citizenship and can vote in all elections, and the other composed of those who didn’t, and can vote only in federal elections.

At the root of all the lawsuits is a seeming contradiction between federal voting law and the proof of citizenship laws passed by Kansas, Alabama, and Georgia. States control most aspects of the voting process. But the National Voter Registration Act, which aims to make registering to vote as easy as possible, bars them from imposing additional requirements of would-be registrants — like proof of citizenship.

Kobach, a former GOP operative, pushed hard for Kansas’ law, and helped write strict immigration laws passed by several states. He has argued that the voter registration law is needed to stop non-citizen voting, but has produced no evidence that non-citizen voting is happening on a significant scale in the state.