ATLANTA — A federal judge ruled Monday that forcing Georgia to scrap its electronic voting machines in favor of paper ballots for the upcoming midterm elections is too risky, though she said she has grave concerns about the machines that experts have said are vulnerable to hacking.

U.S. District Judge Amy Totenberg's ruling means the state won't have to use paper ballots for this year's midterm elections, including a high-profile gubernatorial contest between the state's top elections official, Republican Secretary of State Brian Kemp, and Democrat Stacey Abrams, a former state House minority leader who's trying to become the country's first black, female governor.

Voting integrity advocates and Georgia voters sued state and county election officials, arguing the touchscreen voting machines Georgia has used since 2002 are vulnerable to hacking and provide no way to confirm that votes have been recorded correctly because there's no paper trail.

Georgia has repeatedly ignored warnings from cybersecurity experts and federal officials about the insecurity of electronic voting machines with no paper record, the voting integrity advocates argued. A Sept. 6 report from the National Academy of Sciences report they cited says all elections should be conducted with "human-readable paper ballots" by 2020 with every effort made to use them in this year's general election.

The case is being watched closely because Georgia is not the only state that uses the machines. Four other states, along with more than 300 counties in eight other states, exclusively use touchscreen voting machines that provide no paper record, according to Verified Voting, a nonprofit group focused on ensuring the accuracy of elections.

Kemp, who rejected federal offers of assistance with election system security in 2016, has conceded that the current machines should be replaced. But he and other election officials argue the machines are still secure and a last-minute change would be costly and cause chaos. Early voting starts Oct. 15 for the Nov. 6 midterm elections.

Kemp earlier this year established a commission to look at changing machines and last month called for proposals to implement a system with voter-verifiable paper records in time for the 2020 presidential election.

Voting integrity advocates noted that Georgia already uses paper ballots for absentee voting and for provisional voting at polling sites and argued the state could easily scale up to accommodate all voters.

State elections director Chris Harvey testified at a hearing last week that the state doesn't have enough optical scanners to handle such an increase in the volume of paper ballots and likely can't secure enough in time. It would also be tough to get enough ballots and to conduct necessary election worker training and voter education, he testified.

But paper-ballot elections are easier, and costs would be offset by huge savings because election officials wouldn't have to test, program, transport, set up, take down and secure the state's 27,000 voting machines and account for all the memory cards, lawyers for the voting integrity advocates argued.

They said the state's 891 optical scanners should suffice and, if not, that the state can easily get more. Election workers are already trained on paper ballots for provisional voting, they said.

Under questioning by lawyers for the Coalition for Good Governance and for a group of Georgia voters, election officials didn't say it would be impossible to switch by November. Those seeking to change to paper ballots argued that logistical difficulty and expense are not valid reasons to continue to use a system they say is not secure.

In addition to worries about the machines, voting integrity advocates also point to other concerns in Georgia that they say make a more secure system imperative.

Security experts last year disclosed a gaping hole that exposed personal data for 6.7 million Georgia voters, as well as passwords used by county officials to access election-staging files. That hole still wasn't fixed six months after it was first reported to election authorities.

Kemp's office blamed the Center for Elections Systems at Kennesaw State University that managed the system. But ultimately, it reported to his office.

Less than a week after the lawsuit was filed in July 2017 demanding the touchscreen system be replaced, the server that had been accessed was wiped clean by staff at Kennesaw State. Kemp denied ordering the data destruction or knowing about it in advance.