An odd repercussion has arisen over Kansas’ proof-of-citizenship requirement for residents who register to vote.

So odd that the American Civil Liberties Union of Kansas has asked a state court to put an end to the two-tiered voter registration system Secretary of State Kris Kobach has created, a system that critics call the law’s “unintended consequence” or, less kindly, “collateral damage.”

Kansas now requires residents to produce citizenship documents, typically a birth certificate or passport, to register to vote. That law, championed by Kobach, took effect in 2013.

But citizens have long been allowed to use a federal form to register. That form requires registrants to sign a statement, under penalty of perjury, that they are U.S. citizens. No documents needed.

So what to do about Kansas residents who complete the federal form, which courts have said must be accepted by states?

This is the fallout critics are decrying: They are allowed to vote, but Kobach decided their ballots will be treated specially. Only votes in federal races are counted. If they cast votes in state and local races, those votes are not counted.

“It’s a great example of the law of unintended consequences,” said Mark Johnson, a Kansas City lawyer who teaches election law at the University of Kansas School of Law.

“So now we have people who can vote for Congress and the president, but not for governor, for the statehouse, in other elections we have every year,” Johnson said.

The ACLU filed a motion this month calling Kobach’s “dual system” illegal.

The motion said Kobach, the state’s top election official, didn’t have legislative authority to put it in place and that it unconstitutionally grants differing voter rights.

“The secretary of state adopted this kind of informal rule that treats people who use the federal form differently from people who use the state form,” said Doug Bonney, the ACLU of Kansas’ legal director.

“This is just making up a system that needs more thought and, at the very least, needs legislative authority.”

Bonney said because ballots include federal, state and local races, opening the ballots of certain voters to count only the federal part also could violate ballot secrecy, he said.

The ACLU motion came after Shawnee County District Judge Franklin Theis ruled Kobach had exceeded his authority, dismissing Kobach’s request for summary judgment in his favor. In his own filing, Kobach asked that he be allowed to immediately appeal Theis’ decision.

Kobach had also lost in another maneuver.

The ACLU’s suit was filed on behalf of two voters who registered using the federal form, which doesn’t require proof of citizenship. The secretary of state’s office found citizenship documents for the two plaintiffs through the motor vehicle office and completed state voter registrations for them.

Kobach then argued they no longer had standing to sue. Theis rejected that reasoning.

Bonney said appeals in the case, Belenky v. Kobach, probably will go on for months.

Kobach, who couldn’t be reached for comment, has said he again will ask the U.S. Election Assistance Commission to alter the federal voter registration form so it requires Kansas registrants to provide proof-of-citizenship documents.

Such citizenship documents are necessary to protect elections from noncitizens who attempt to vote, Kobach has said.

But Bonney maintained protections were already in place — a person’s signature attesting he or she is a U.S. citizen plus the government’s authority to prosecute violators.

“There hasn’t been any significant problem with citizen impersonation fraud,” Bonney said. “This was a solution looking for a cause, and the result is a lot of collateral damage like this bifurcated system.”

Johnson said the attempt to eliminate a few possible cases of fraud should be weighed against a process that potentially keeps thousands from voting.

“With every one of the hurdles to voting, a certain percentage of the electorate says they’re not going to bother, and they end up not voting,” Johnson said. “This is trying to make something perfect, but with the effect of potentially ruining a very, very reliable system.”