Touch-screen electronic voting machines in at least four states pose a risk to the integrity of the 2012 presidential election, according to a Monitor analysis.

In four key battleground states – Pennsylvania, Virginia, Florida, and Colorado – glitches in e-voting machines could produce incorrect or incomplete tallies that would be difficult to detect and all but impossible to correct because the machines have no paper record for officials to go back and check.

While many state officials laud the accuracy of e-voting machines, mechanical and software failures are not a new problem. What makes the risk more serious this year is that polls project a close election, and e-voting problems in any of the four states in question could affect who wins the presidency.

"No matter how unlikely it seems now, there's a chance that this election will be so close that it could be flipped by a single voting machine problem in a single place in any one of those states," says Edward Felten, a professor at Princeton University in New Jersey who has analyzed e-voting machine weaknesses. "To avoid that, it's key to have a record of what the voter saw – and that means having a paper ballot or other paper record."

Paper verification of votes has proved to be a vital backstop to ensure that voting-machine software is not corrupt and that programming errors did not affect the accuracy of electronic vote tallies. Voting machines have at times "lost" thousands of votes or even "flipped" votes from one candidate to another, and total breakdowns are not unheard of.

For example:

In 2006, some 18,000 votes were electronically "lost" by e-vote systems in a single Florida congressional race with no paper backup or ballots available to review.

In May 2011, voters in Pennsylvania’s Venango County complained that paperless electronic touch-screen machines were "flipping their choices from one party to another," according to a report by Verified Voting, a nonprofit group in Carlsbad, Calif., that tracks voting machine use nationwide. After an inconclusive audit of election results, the county simply decided to use paper ballots counted by optical scanners in future elections.

In March, an e-voting system in Florida’s Palm Beach County experienced a "synchronization” problem in a municipal election. The election software attributed votes to the wrong contest and the wrong candidates won. Thankfully, paper ballots existed. After a court-ordered recount, results were changed and two losing candidates were declared winners.

More than 1,800 voting machine problems were reported to election protection hotlines during the 2008 general election, according to Verified Voting. Such election failures mattered far less in 2008 because Barack Obama won by a landslide. But this year, the loser might be likely to demand a recount if the winning margin is small. In states that still use Direct Recording Electronic (DRE) machines – touch-screen voting equipment that lacks any paper verification – that could be a problem. [Editor's note: The original stated the full name of DREs incorrectly.]

"Without a paper trail there's no opportunity to check, so then you just have to rely on faith that the software is functioning properly and capturing votes properly," says Pamela Smith, president of Verified Voting. "Maybe the machine is working OK right now. But if there is a bug or glitch, there's nothing to go back to."

After the controversy over "hanging chads" in Florida in the 2000 election, touch-screen e-voting machines proliferated nationwide as the Help America Vote Act of 2002 helped states pay for new equipment. Most states have since replaced e-systems that lack paper verification with paper ballots counted by optical scanners. While scanners can also fail, the paper ballots are there to be recounted.

But 17 states still use paperless DREs, according to Verified Voting. Among those, four are expected to see election results close enough to potentially demand a recount.

"Most of the country has gone to some sort of paper-based optical or electronic system," says Peter Lichtenheld, vice president of operations for Austin-based Hart InterCivic, one of four major voting machine companies in the US. "In counties that have decided to stay with DREs, they've put in people and procedures to make them more secure."

For example, most states now run preelection software tests on the machines to verify that they are counting correctly. The machines are "sealed" against tampering and, increasingly, they are monitored by surveillance cameras even in off-use periods. Memory cards in the machines should retain votes, even in a power failure, but have not always done so.

To critics, however, reliance on electronic methods alone as a backup means that the machines are, in essence, checking themselves. Only a paper document checked by the voter ensures that the vote was recorded correctly and is immune to system failures or even cyberattack.

In Pennsylvania, 50 of 68 counties have paperless equipment as their standard voting system, Verified Voting data show. Those machines serve some 7 million of about 8.5 million registered voters statewide.

In Virginia, 127 of 135 counties use paperless DREs, accounting for 3.7 million of the state’s 5 million registered voters, according to Verified Voting.

Colorado is shifting to mail-in paper ballots, but the transition isn't complete. Jefferson County, the state’s fourth most populous, is using paperless DREs as well as mailed ballots. So many of its 320,000-plus "active" registered voters will vote on the machines – more than enough to tip a tight race, says Ms. Smith of Verified Voting.

In Florida, all counties are required by law to have paper backups for their voting machines by 2014. Even so, a small but potentially significant number of disabled voters statewide still will use paperless touch-screen machines this year. Although only a few thousand votes may be cast on those "accessibility" machines, it could still be enough to throw the race if the state's vote tally were to end up as close as it was in the 2000 presidential election, when George W. Bush controversially won by 537 votes.

State officials stand by the machines.

"These DREs have been one of the more reliable pieces of equipment we've had," says Donald Palmer, secretary of Virginia's Board of Elections, the state's most senior election official. "We haven't had any major problems with them."

In fact, Colorado’s Jefferson County recently had to conduct a recount in a congressional race, in which votes cast on paperless DREs were included. Significantly, both candidates accepted the result although there was no paper to confirm that the machines had recorded the votes correctly.

"We think we have the right processes in place to make sure everyone is able to vote and that their votes count," says Andrew Cole, a spokesman for the Colorado Secretary of State's office.

Still, Princeton’s Professor Felten has put all four states on his top 10 states “at risk” of an e-voting meltdown. Among the factors going into the the list is the effectiveness of a state’s vote-audit laws.

California, for example, is lauded because its post-election audits draw statistical comparison between paper totals and voting machine tallies to ensure the machines are accurate. In contrast, Virginia has no post-election audit and limited provisions for a recount in state law in case machine vote-count problems are detected. Similarly, Florida state laws are such that a recount may not be permitted even if a machine is known to have malfunctioned.

"Florida's post-election audit law is absolutely atrocious and does not afford the voters any certainty that their votes have been accurately counted," says Ion Sancho, supervisor of elections in Florida’s Leon County. "Because our laws only allow erroneous totals to be corrected on the basis of fraud, a machine could break down, but if there's no fraud, our laws would still not allow us to correct those erroneous totals."

The small number of voters who will use paperless DREs in the state limit the chances of an e-voting meltdown there, he acknowledges. But it is a concern. He notes that the blatant mistake made by e-voting machines in Palm Beach might have never been corrected had that been a statewide election, since there was no obvious fraud. "State law doesn't require it," he says.

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"I'm hopeful," he adds, "that we can get through to 2014 without an election disaster like 2000 and finally get rid of all these [paperless] machines once and for all."

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