ATLANTA (AP) — Time and money are running short for states to replace aging or inadequate voting machines before the 2020 presidential primaries, according to a report released Tuesday.

State and local election officials in 31 states say they want to replace their voting equipment before the elections, but the vast majority said they don't have enough money to do so, according to The Brennan Center for Justice at NYU's School of Law.

"We basically have this year and then it's too late," said Lawrence Norden, deputy director of the center's Democracy Program and author of the report.

It can take months to decide on replacement machines, secure the funding, develop security protocols, train workers and test the equipment.

States received $380 million in election security grants from Congress last year, but experts have said that's merely a down payment on what is needed.

Pennsylvania received $13.5 million from the federal government, but that's just a quarter of what it would cost to switch to voting machines that use paper ballots, said J. Alex Halderman, director of the Center for Computer Security and Society at the University of Michigan.

"Without further federal assistance, we risk that new equipment and other critical improvements won't be in place for many years," Halderman said in congressional testimony last month. "With the 2020 election on the horizon, the next major target for foreign cyberattacks, we need to act before it's too late."

In 2016, Russian hackers are believed to have targeted the nation's voting systems, searching for vulnerabilities. The nation's intelligence community has said there is no evidence of votes being changed, but warn of the continuing danger posed by foreign governments interested in undermining U.S. elections.

Congressional efforts to send more election security money to the states have yet to gain momentum despite some bipartisan support.

The most urgent concern centers on the 12 states that use, either statewide or in certain local jurisdictions, electronic voting machines that do not produce a paper record so voters can verify their choices before they cast their ballot. Experts say these machines are vulnerable and that hackers could manipulate the outcome without detection.

Of these states, Delaware has set aside money to buy replacement machines while lawmakers in Georgia and South Carolina are considering proposals to do the same. Louisiana's plan to replace voting machines was delayed amid a dispute over the bidding process.

Officials in Pennsylvania, New Jersey, Kansas and Kentucky have called for new machines, but efforts to secure the money haven't gained much traction, according to the Brennan Center report. Indiana, Mississippi, Tennessee and Texas do not appear to be taking major steps at this point to replace their paperless machines by 2020, the report said.

Cybersecurity experts and officials with the U.S. Department of Homeland Security say a paper record is essential to securing the nation's elections and that rigorous audits are needed to detect any malfunction or efforts to interfere.

There is less a consensus on a return to paper ballots that are filled out by hand, although cybersecurity experts largely prefer them. That debate is playing out in Georgia as state lawmakers consider replacing the state's paperless machines. Democrats and voting advocates say systems that use those types of ballots are the most secure and cost-effective options.

Republicans have thrown their support behind a more expensive "ballot-marking" voting machine. It features an electronic touchscreen that prints out a ballot that is then verified by voters before being cast.

They say this allows for one system used by all voters, including those with disabilities, while also offering a secure method for post-election audits.

Elsewhere, California has already allocated $134.3 million for counties to upgrade or replace old voting systems. It plans to decertify certain machines.

Norden, with The Brennan Center, said states can't expect the federal government to cover everything, but the federal government can't leave national security to state and local governments either.

"There needs to be an acknowledgement that everyone has a responsibility for this at the federal, state and local level," he said. "There has been an attempt to shift responsibility from one to the other and too often that means nobody is responsible."

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