Topeka ? A dispute about requiring voters to show identification at the polls or when they request advance ballots threatens to cost the state $27 million and open Kansas to potential lawsuits.

Gov. Kathleen Sebelius, a Democrat, and Secretary of State Ron Thornburgh, a Republican, disagree over how best to bring the state into compliance with last year’s federal election law, the Help America Vote Act. Thornburgh is the state’s chief elections officer, but any bill must pass muster with Sebelius because she has veto power.

Thornburgh backed a bill requiring all voters to show proof of their identities at the polls or when they seek advance ballots. Sebelius vetoed it, preferring instead to impose the requirement only on new voters — something Thornburgh insists would be difficult to administer.

A bill has to be in place by next year, or the state risks losing more than three-quarters of the money it would receive under the federal law to replace outdated voting machines, purchase equipment to make voting accessible to the people with disabilities, improve voter education and enhance training for poll workers.

And, under the federal law, if the state does not upgrade voting machines, it can be sued for denying people access to the ballot box.

“In the long run, it’s going to be problematic for us,” Thornburgh said during a recent interview. “Sooner or later, you have to do something.”

Sebelius vetoed the voter identity bill April 18, while legislators were taking their annual spring break. She had hoped they would consider a new proposal after their wrap-up session began April 30.

They did not, and the House voted to sustain the veto.

“I was hopeful the Legislature would deal with the issue,” Sebelius said during her most recent news conference.

The Help America Vote Act promised states $3.9 billion in aid, with Kansas expecting to receive $34.5 million over four years, with the first $7.5 million due after the next federal fiscal year begins Oct. 1.

Thornburgh believes the state will have no problem securing that first installment, even with a plan he expects will be “very vague.”

“Next year, we’ve got to get legislation passed,” Thornburgh said.

The federal law mandates that states require proof of identity only from new voters. Sebelius argues the state should not go beyond that requirement.

She said some Kansans — particularly elderly residents of nursing homes — may no longer have driver’s licenses. She said the change would undercut the use of advance ballots. She also said the new requirements, if imposed for all voters, could depress turnout. Sebelius also said there was no evidence of significant voter fraud warranting the measure.

But Thornburgh, asked about the possibility an ID requirement would stifle turnout, said, “I cannot find any shred of evidence that’s true.”

He said imposing the ID requirement only for new voters would create different classes of citizens, making educating potential voters more complicated.