Secretary of State Kris Kobach is seeking authority to hold bifurcated elections so that people who register to vote without showing proof of U.S. citizenship would only be allowed to vote in federal races.

Topeka ? Kansas Secretary of State Kris Kobach urged a Senate committee Tuesday to pass a bill that would authorize his office to block an estimated 18,000 registered voters from casting ballots in state and local elections if they registered under a federal system that does not require people to show proof of U.S. citizenship.

“The first reason we have this bill is to preserve the integrity of our proof of citizenship requirement,” Kobach said.

Last year, a federal judge in Kansas City, Kan., granted a temporary injunction blocking Kobach’s office from enforcing that requirement on voters who had registered using a federal system that does not require proof of citizenship.

Secretary of State Kris Kobach is seeking authority to hold bifurcated elections so that people who register to vote without showing proof of U.S. citizenship would only be allowed to vote in federal races.

That ruling, however, applied only to a person’s right to vote in races for president or Congress. Kobach then attempted to enact regulations that would have required those people to cast provisional ballots so only their votes in federal races would be counted while votes in any other races or ballot issues would be thrown out.

But a judge in Shawnee County overturned that regulation, saying Kobach had no legal authority to maintain two separate voter rolls or to conduct what he called a bifurcated election.

The bill being considered in the Senate Ethics, Elections and Local Government Committee, would give him that authority, at least until the federal courts make final rulings on cases challenging the law.

During the 2016 elections, Kobach’s office said there were more than 17,000 people who fell into the category of people who’d registered without showing proof of citizenship. During his testimony Tuesday, Kobach argued that there could be as many as 18,000 non-U.S. citizens currently on the Kansas voter registration rolls.

However, that number, which Kobach said he submitted as evidence in one of the federal court cases challenging the proof of citizenship law, was based on the same widely debunked study by researchers at Old Dominion University that President Donald Trump has used to assert that millions of noncitizens voted illegally in the 2016 election.

The study used large-sample survey data from the 2008 and 2010 elections that suggested roughly 15 percent of the adult non-U.S. citizen population in the country was registered to vote, and that as many as 6 percent actually had cast ballots.

That study was harshly criticized by other researchers who questioned the methodology and noted that many of the people in the original study who were identified as noncitizens probably were misclassified.

That’s because in any survey a very small percentage of people will accidentally check the wrong box or give an incorrect answer. But in a large-sample survey, those errors can produce a seemingly large number of people who claim to have a particular characteristic — like being a noncitizen who voted — when, in fact, they don’t.

Only four other people testified in favor of the bill, all of them county election commissioners whom Kobach himself either appointed or reappointed to their positions. In Kansas, the four largest counties — Johnson, Sedgwick, Shawnee and Wyandotte — have appointed election commissioners while in the other 101 counties, the county clerk is the chief election officer.

Sedgwick County Election Commissioner Tabitha Lehman said her office has verified that 12 noncitizens have voted since 2004. She said one way officials know that is by attending naturalization ceremonies held in Wichita and signing people up to vote as soon as they become citizens, only to find out they are already registered and have cast ballots in previous elections.

She also said another case of a noncitizen voting in Sedgwick County had been confirmed as recently as last week.

Although Kobach now has authority to prosecute election crimes, he has only filed charges in a handful of cases, none of them involving noncitizens who voted illegally. When asked by reporters why he hadn’t filed any, he said that in most cases officials only learn that a noncitizen has voted long after the statute of limitations has expired.

When reminded of Lehman’s statement that one had been confirmed only last week, he said: “That one is one we may be looking at to prosecute because that person actually did vote, I believe in the 2014 election, but in most of these instances we don’t discover the crime that the noncitizen committed until 10 years after the crime is committed.”

But Rabbi Moti Rieber, of the group Kansas Interfaith Action, said the small number of noncitizens who may be voting does not justify the thousands of otherwise eligible voters being barred from voting because of the citizenship law.

“Eighteen thousand Kansans will lose their right to vote if this bill passes,” Rieber said.

Doug Bonney, an attorney for the American Civil Liberties Union of Kansas who is involved in the lawsuits still pending in federal court, said passage of the bill would only result in more litigation.

“This law would be challenged, if it were to pass, on constitutional grounds under the Kansas State Constitution as violating principles of equal protection and due process,” he said.

U.S. District Judge Julie Robinson has scheduled a hearing for March 3 to hear oral arguments in the case challenging the proof of citizenship law. That case will decide whether the temporary injunction she issued last year will be lifted or made permanent.