On Election Day this November, about 1 in 4 Americans will vote using a device that never lets the voter see a copy of his or her vote on paper.
The idea of relying on such machines has troubled some security experts for years. And this year the stakes may be even higher, because one candidate is charging that the election is rigged, and government officials have warned that state election systems have been targeted by foreign hackers with ties to Russia.
Five states exclusively use voting machines that lack the kind of independent paper trail needed to do a convincing recount, according to a nonprofit, nonpartisan group called Verified Voting. Those states are New Jersey, Delaware, Georgia, Louisiana and South Carolina.
"And then there are another nine states that have paperless voting machines in some jurisdictions," says Pamela Smith, president of Verified Voting.
In Pennsylvania, considered a battleground state, those machines are used in a majority of counties.
"On a scale of all of the states, I would say that Pennsylvania would be my biggest concern," says Smith.
Pennsylvania also worries Avi Rubin, a computer security expert at Johns Hopkins University. "What do we do if, at the end of the election, it comes down to Pennsylvania and there's a challenge saying, you know, these machines were corrupted?" Rubin asks. "We can't do recounts. We don't have paper ballots. We just have to live with those machines."
But Gerald Feaser, director of elections and voter registration for Pennsylvania's Dauphin County, thinks the paperless machines have a lot of advantages and are a dependable, time-tested technology. His county started using the Danaher 1242 paperless voting machine back in 1985, he points out.
"When I first turned 18 and started voting myself, this was the first machine I ever voted on," says Feaser. "This is the only voting machine I've ever known."
He points to the plug in the electric outlet and says this is the only connection this machine has with the outside world. And while a hacker could try to sneak into a warehouse or polling place to tamper with the hardware, Feaser says his county's nearly 500 machines get thoroughly checked out and then get numbered security seals before they are delivered to polling places.
"I could take this voting machine, drop it off in the middle of Red Square in Moscow, and the Russians couldn't hack into it," says Feaser.
At the end of election night, the machine spits out a long paper receipt showing the total votes recorded for each candidate. But that kind of paper trail is not the kind of paper backup you really need, say experts in voting security. Without a hard copy of the individual ballot that each voter checked, they maintain, it's not possible to do a legitimate recount.
"They don't have a separate record that the voter got a chance to see and confirm was correct at the time that they voted," says Smith, who notes that this type of machine gives you "nothing independent of the software in the machine."
Computer security specialists note that many jurisdictions use equipment provided by a small number of vendors.
"So an attack that works against one county will work against many counties," says Dan Wallach, a computer scientist at Rice University who studies voting machine security.
Plus, other nations are surely aware of how the Electoral College system works and could target battleground states in clever ways, says Wallach, adding that he finds it disquieting when election officials simply dismiss concerns.
"Because that suggests some people don't understand what it means to be facing a nation-state adversary," he says. "It's important to take the threat seriously."
Federal officials have warned that this year foreign hackers have targeted the voter registration systems in multiple states. And the Department of Homeland Security recently offered to help states review their election systems for vulnerability.
"We in Pennsylvania thought that that was a good idea — to take advantage of those services," says Marian Schneider, Pennsylvania's deputy secretary for elections and administration
She says she has confidence in local officials' commitment to a fair and smooth election.
"I think the rhetoric about cheating and rigging is very irresponsible," says Schneider.
When asked if, in the event of a challenge, Pennsylvania would be able to do a convincing recount or audit, she replies that "the systems will be examined at that point. At this point it's really speculation."
After all, state law doesn't trigger a recount unless the difference between candidates is very, very small — just one half of 1 percent of the total votes cast.
State officials in Pennsylvania certify voting systems that counties purchase and use, Schneider says.
"We're committed to making sure that voting systems are secure, accurate and verifiable going forward," she says.
But it is expensive to run elections. If the legacy voting systems are going to be replaced with something different, Schneider notes, "there needs to be a significant infusion of cash."
KELLY MCEVERS, HOST:
On election day, about 1 in 4 Americans will cast their votes on a so-called paperless machine, which means they'll never get to see a hard copy of their vote. Security experts worry about the lack of an adequate paper trail, especially this year, given concerns about foreign hacking and the campaign rhetoric about rigged elections. NPR's Nell Greenfieldboyce reports from the battleground state of Pennsylvania.
NELL GREENFIELDBOYCE, BYLINE: I've come to Harrisburg to see the Danaher 1242, a voting machine also known as the ELECTronic. Get it? The ELECTronic? Folded up, this contraption looks like a huge, beige suitcase.
JERRY FEASER: Lift the latches. And then gently lifting up...
(SOUNDBITE OF VOTING MACHINE)
GREENFIELDBOYCE: Jerry Feaser is director of elections for Dauphin County. Once the machine is vertical, he opens its doors.
(SOUNDBITE OF VOTING MACHINE)
GREENFIELDBOYCE: There's a panel with blinking lights, the candidates' names. It's a familiar sight to voters here. They've used these machines for over 30 years.
FEASER: When I first turned 18 and started voting myself, this was the first machine I ever voted on. This is the only voting machine I've ever known.
GREENFIELDBOYCE: Now, this year, there's concerns about hacking. But Feaser says, consider this. These machines aren't connected to the internet. The only link to the outside world is the plug in the electrical outlet. And while a hacker could try to sneak in and tamper with the hardware, Feaser says these machines get checked and decked out with numbered security seals before going to polling places.
FEASER: I could take this voting machine, drop it off in the middle of Red Square in Moscow, and the Russians couldn't hack into it.
GREENFIELDBOYCE: At the end of election night, the machine spits out a paper receipt showing the total votes recorded for each candidate.
(SOUNDBITE OF VOTING MACHINE)
FEASER: And tear off the tape results.
GREENFIELDBOYCE: (Laughter) How long is that piece of paper? That's, like, a 10-foot-long piece of paper there.
FEASER: At least.
GREENFIELDBOYCE: But critics say this paper is not the kind of paper backup you really need. Without a hard copy of individual ballots, you can't do a real recount.
PAMELA SMITH: They don't have a separate record that the voter got a chance to see and confirm was correct at the time that they voted - nothing independent of the software and the machine.
GREENFIELDBOYCE: Pamela Smith is president of a nonpartisan nonprofit called Verified Voting. She says five states exclusively use voting machines that lack an independent paper trail, New Jersey, Delaware, Georgia, Louisiana and South Carolina.
SMITH: And then there's another nine states that have paperless voting machines in some jurisdictions.
GREENFIELDBOYCE: In Pennsylvania, a battleground state, those machines are used in a majority of counties.
SMITH: You know, on a scale of all of the states, I would say Pennsylvania would be my biggest concern.
GREENFIELDBOYCE: Others agree, like Avi Rubin, a computer security expert at Johns Hopkins University.
AVI RUBIN: What do we do if, at the end of the election, it comes down to Pennsylvania, and there's a challenge saying, you know, these machines were corrupted? We can't do recounts. We don't have paper ballots. We just have to live with those machines.
GREENFIELDBOYCE: At a time when Donald Trump is warning of a rigged election - here's what he said during one recent visit to the state.
(SOUNDBITE OF ARCHIVED RECORDING)
DONALD TRUMP: The only way we can lose, in my opinion - I really mean this - Pennsylvania is if cheating goes on. I really believe it.
GREENFIELDBOYCE: That doesn't sit well with Marian Schneider. She's Pennsylvania's deputy secretary for elections and administration.
MARIAN SCHNEIDER: I think the rhetoric about cheating and rigging is very irresponsible.
GREENFIELDBOYCE: Concerns about hacking, on the other hand - federal officials have warned that state election systems have been probed by hackers with ties to Russia. The Department of Homeland Security offered to help states review election systems for vulnerabilities.
SCHNEIDER: And we in Pennsylvania thought that that was a good idea - to take advantage of those services.
GREENFIELDBOYCE: She has no evidence of any tampering. I asked her, if the election is close, and there's a challenge to the results, could Pennsylvania do an adequate audit or recount?
SCHNEIDER: The systems will be examined at that point. I mean, that's - at this point, it's really speculation.
GREENFIELDBOYCE: She says state law doesn't trigger a recount unless the difference between candidates is very, very small. Recent polls in Pennsylvania show that Hillary Clinton currently has a solid lead. Nell Greenfieldboyce, NPR News. Transcript provided by NPR, Copyright NPR.