Topeka ? Republicans pushed a bill through the Kansas House Thursday requiring potential voters to prove their U.S. citizenship ahead of this year’s election, although GOP senators are divided on whether the state will be ready to enforce the rule.

The House approved the bill, 81-43, with all of the votes for it coming from Republicans. It would impose the proof-of-citizenship requirement for people registering to vote for the first time in Kansas starting June 15, more than six months ahead of schedule and in time for the normal surge before a presidential election.

Secretary of State Kris Kobach, who introduced the bill, says the rule combats election fraud, but critics believe it will suppress turnout among poor, minority and elderly voters.

Legislators approved a proof-of-citizenship rule last year but — at the Senate’s insistence — it’s not scheduled to take effect until Jan. 1, 2013. The Senate has a large GOP majority, but its leaders are less conservative than Kobach and his allies and hesitated to move too quickly to impose the requirement.

Top Republican senators said a key issue for them remains a $40 million upgrade of the state Division of Vehicles computer system that handles driver’s licenses. The project will allow the division to store electronic copies of birth certificates and other documents proving a driver’s citizenship and transfer them to election officials as needed.

Officials in the Department of Revenue, which oversees the division, have said repeatedly that they think the system will be ready by June. But GOP leaders in the Senate want a guarantee, and Ethics and Elections Committee Chairwoman Terrie Huntington, of Fairway, said she’ll probably delay action on Kobach’s bill for several weeks to get such assurances.

“It really all centers around the ability of the Department of Revenue to have the motor-vehicle computer system working,” Huntington said. “They’re thinking that it might be, but they cannot guarantee that it will.”

Kobach has been frustrated by the focus on the Division of Vehicles computer project, arguing repeatedly that it’s not necessary for it to be finished to move ahead with a proof-of-citizenship requirement. He’s said it will prevent illegal immigrants and other non-citizens from registering to vote, and it makes sense to have the rule in place ahead of the busiest registration period between presidential elections.

His office said it identified 32 non-citizens on Kansas voter rolls last year. Critics note Kansas has about 1.7 million registered voters and that reported cases of illegal immigrants voting remain rare.

Some GOP senators have no problem with moving up the date of the proof-of-citizenship rule. Sen. Dick Kelsey, a Goddard Republican, said he’s confident that Kansans who will need free birth certificates to prove their citizenship will be able to get them to register, as state law currently provides.

But the Division of Vehicles’ computer upgrade is an important issue for other Republicans because they believe its completion will simplify voter registration.

Part of the division’s project is a response to a federal law pushing states to verify that residents are living in the U.S. legally before issuing them driver’s licenses. Kansas already requires proof of legal status when it issues a new license, but with the computer upgrade, the same proof will be required the next time anyone in Kansas renews a license.

By 2019, every Kansas license is supposed to indicate whether someone is a citizen and the Division of Vehicles must store the supporting documents electronically. Then, a Kansas driver’s license will be one of 13 documents that proves citizenship.

Department of Revenue spokeswoman Jeanine Koranda said June 15 remains a reasonable date for completion of the computer upgrade. But she called the project “massive” and acknowledged, “Delays are possible.”