(CBS) - Four of of ten American voters will be casting ballots this November on equipment that's different from what they used in 2004.
One reason is the doubts raised about ATM-syle electronic touch-screen machines, which have prompted half a dozen states to turn them off and turn back to paper ballots.
In fact, at least 55 percent of Americans voting this November will vote on paper ballots that will be counted by optical scanners, according to Virginia-based Election Data Services, Inc.
"That's an all-time high for optical scan usage in this nation," says EDS President Kimball Brace.
Only one-third of voters will be using touch-screen systems, according to EDS.
"Electronic system usage will go down in 2008 for the first time since we started collecting data in 1980," Brace says.
In the key presidential battleground of Ohio, the switch away from touch-screens came after Secretary of State Jennifer Bruner took office last year and commissioned a top-to-bottom review of the Diebold machines used in 53 of Ohio's 88 counties.
"We studied these systems and all the systems in use in Ohio and the most vulnerable to risk are the touch-screen voting machines," Brunner says. "The software is antiquated, and it's unstable."
Last week Brunner sued the manufacturer, now known as Premier Election Systems, for breach of contract, citing recent elections where votes were dropped when memory cards were uploaded.
"There have been no votes lost, just votes that are missed and hours later or days later recovered," Brunner says. "We have a system that is performing inadequately."
"We are in fact in compliance with the terms of the contracts," says Chris Riggall, a spokesman for Premier, which has voting equipment in 34 states.
"We have provided a high-quality system," Riggall says.
Still, Brunner forced the state's most populous county, Cuyahoga, which includes Cleveland and has suffered computer crashes in recent elections, to abandon its touch-screens for optical scanners. Three other Ohio counties followed suit.
Bolstered by $4.5 million in federal funds, Brunner has also ordered every county in the state to print enough paper ballots to supply a quarter of the electorate expected to show up at the polls.
"If there's a machine failure or a power outage, or some kind of misprogramming with the machines, it will enable people to keep voting," Brunner says.
The national rush toward touch-screens began after Florida's too-close-to-call presidential race between Al Gore and George Bush in 2000 led to the spectacle of election officials trying to discern voter intent by studying hanging chads on punch card ballots.
Congress passed the Help America Vote Act in 2002 with funds for states to upgrade their equipment. States spent at least $2 billion by the end of 2007, according to the Election Assistance Commission.
Florida led the way to touch-screens, but in 2006, experienced another meltdown in Sarasota, where about 18,000 ballots cast on machines made by ES&S registered no vote in a hard-fought congressional race decided by fewer than 400 votes.
The Sarasota machines contained no paper trial - a scroll, stored inside a machine, that displays a person's ballot choices before the "vote" button is hit - so the recount could not recover any lost votes.
When Charlie Crist became governor last year, he deep-sixed Florida's touch-screens. A Tampa electronics recycler was tapped to pick up nearly 30,000 of them.
The two closest swing states in the last election have made a change too.
Iowa became the latest state to disconnect touch-screens, when Governor Chet Culver signed a bill in April to replace the machines in 19 counties that used them with optical scanners.
New Mexico Governor Bill Richardson moved his state from a hogdepodge of voting methods onto a single paper-based system in 2006.
Most California voters now use optical scanners, with only three of the state's 58 counties using touch-screens.
In Maryland, which has experienced glitches with its paperless touch-screens, Governor Martin O'Malley pushed through a plan to abandon them in 2010.
"What has happened since Florida 2000 is we've taken a problem that was a disaster for that election and made it exponentially worse," says John Bonifaz, legal director of the watchdog Voter Action.
"These machines cannot be trusted for the counting and recording of our votes," Bonifaz says. "Computer scientists around the country have demonstrated that in less than 60 seconds one of these machines can be broken into and can infect the entire system on which people are voting."
However, machine makers are quick to retort, there's been no documented case of hacking during an actual election, despite what professors have been able to do to a single machine in a lab setting.
"Touch-screen voting machines have proven to be accurate, reliable, and secure time and time again," says Ken Fields, a spokesman for ES&S.
Fields says the ES&S equipment deployed in 43 states complies "with rigorous standards for quality, accuracy, security, and reliability."
Sequoia, which supplies 17 states with voting equipment, points to poll worker training as a cause of recent election ills. The Election Assistance Commission estimates that two million poll workers, mostly citizen volunteers, will be needed nationwide November 4.
During the last presidential election, six percent of polling places and four percent of precincts reported having too few poll workers, according to the EAC.
"It is important to note that successful elections necessitate people, processes, and the technology all working together," says Sequoia VP Michelle Shafer.
"Anytime there has been a change in voting equipment, there have been some some doubts and concerns which lessen over time due to familiarity with the new equipment," Shafer says.
Maybe so, but doubts about touch-screens have reached the point that ES&S, Premier, and Sequoia tell CBS News they're no longer getting any new orders for counties switching their systems to touch-screens.
New Jersey Congressman Rush Holt, himself first elected after a recount, particulary worries about voters in 14 states, including his own, Pennsylvania, Indiana, Georgia, and Virginia, that use touch-screen machines that have no voter-verifiable paper trail.
"If all you have is the electronic memory, you can reprint that electronic memory as many times as you want, it's going to say exactly the same thing. And you won't know whether it's right," Holt says. "More than a third of the voters in this country will be voting in an unverifiable way."
Holt's legislation, currently gridlocked on capitol Hill, would allocate millions of dollars to states to offset the cost of printing backup paper ballots and randomly auditing the machines.
"Without an audit, without the ability to audit, it will be unreliable, and without paper record, you can't really audit," Holt says. "This is the central act of democracy. It is the basis for the all the legitimacy of our government and its actions. We believe or at least want to believe that people are put in office by the will of the voters. That's what you need to be able to verify."