Two of the most prominent Republicans in the race for governor locked in a war of words Thursday over a proposal that would replace the state’s aging voting system with paper ballots.

It was the most public rift yet between Lt. Gov. Casey Cagle and Georgia Secretary of State Brian Kemp, the two candidates in the governor’s race with statewide victories under their belts.

And their feud, which escalated throughout the day, signaled the debate over the 16-year-old touch-screen voting network could play a larger role in the race to succeed Gov. Nathan Deal.

It started when Cagle announced he would back a measure to scrap the state's touch-screen voting machines and largely replace them with a paper-based system. He told WABE that a paper-ballot trail ensures "no games" could be played with votes.

Kemp’s most visible job involves overseeing the state’s elections, and his campaign took Cagle’s move as an insult. His spokesman said Cagle sided with “liberal conspiracy theorists” like Stacey Abrams, a Democratic candidate for governor, on the issue.

“Is Casey Cagle that desperate for higher office that he would side with the radical left to tear down Georgia and our institutions?” said Kemp, who added that the decision needs to involve lawmakers, voters and local officials and not “misinformed, craven candidates for higher office.”

Cagle’s campaign manager, Scott Binkley, responded by asserting that conservative Republicans who are backing the measure “just don’t trust the current secretary of state to run a competent election — and with good reason.”

It was a jab about high-profile controversies that have rocked Kemp's tenure. His office in 2015 accidentally disclosed the Social Security numbers and other private information of more than 6 million voters to media outlets and political parties.

And he was forced to move the state's elections work in-house after a private researcher discovered security lapses at a Kennesaw State University center that houses election servers that could have exposed more than 6.5 million voter records and other sensitive information.

A growing number of lawmakers have recently pushed for paper backups to ballots and other new safeguards, worried that a system once considered state-of-the-art is now vulnerable to security risks and hobbled by buggy software.

The state’s 27,000 touch-screen machines now leave no paper record of how people voted, making it impossible to audit elections for accuracy. The machines use the Windows 2000 operating system, which is no longer supported by Microsoft.

The legislation, introduced by state Rep. Scot TurnerR-Holly Springs, with bipartisan support, would replace the touch-screen machines with new voting equipment — primarily optical scanning machines to read paper ballots. It would cost at least $25 million, and Deal's budget proposal doesn't include funding for the plan.

Supporters of the proposal say paper ballots, used by about 70 percent of the nation, are more secure than electronic machines because they can't be hacked. The plan's critics say paper ballots also could be vulnerable to shenanigans, and that overhauling the system is a costly and cumbersome process.

The Democratic candidates for governor were unified in their support of the paper-ballot plan.

Abrams, once the House’s top Democrat, said she broadly supported efforts to “make voting easier and more transparent, including paper ballots.” Her Democratic rival, former state Rep. Stacey Evans, said it was “long past time” for Georgia to embrace a paper-ballot system.

“While I agree with the lieutenant governor’s call, it is disappointing that as leaders of the majority party, the lieutenant governor and the secretary of state have failed to act during their time in office,” she said.

For Kemp and Cagle, the back-and-forth this week may be the start of a new and more bitter phase of the race. Kemp’s spokesman, Ryan Mahoney, capped the tit for tat Thursday with a searing response that painted “Cagle and his attack Chihuahuas” as closet liberals.

“Instead of playing petty politics with our elections systems,” Mahoney said, “Casey Cagle should focus on doing something meaningful this session that actually helps hardworking Georgians — not the political elite.”

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