Voters in Maryland use a touch-screen voting system by Diebold that lets them make and review selections before casting a ballot. For absentee voting and provisional voting, voters use a paper-based system.

The state contends that the transition to electronic voting from paper-based systems has improved the accuracy of the vote count and reduced the number of voter errors.

E-Voting Pros and Cons

But the challenges and benefits of e-voting have come under scrutiny almost since its inception. The arguments and counterarguments mostly center on security: Can the machines be hacked and do they accurately record the voter's intent?

Opponents point to the glitches in other forms of self-service technologies as worrisome indicators that electronic voting will cause similar problems on election day. Proponents argue that such technology works just fine, and that mistakes happen because of the people and processes surrounding its use.

Regardless of the relative seriousness of this release of voting-machine software, the incident has an adverse effect on the perception among public officials, voters, and voting-equipment manufacturers, said Paul Stamp, a security analyst at Forrester Research.

"Electronic voting is the wave of the future, but there remains the question of people putting their trust in unfamiliar equipment," he said. "Without a paper ballot process you are at the mercy of machines that will hopefully work properly."

Stamp noted that, while the merits of e-voting have been fiercely debated, traditional methods of casting ballots are far from perfect. He cited the "hanging chad" problems of 2000 as but one example. "But at least with paper ballots, there is a physical record to consult," he said.

Perception Is Key

Following the 2000 election, the Electronic Frontier Foundation, a nonprofit privacy-advocacy group, pointed to glitches that made it difficult to change votes if people made mistakes. Some electronic machines were not calibrated properly, the EFF said, which made it easy to vote for the wrong person.

And there were indications that the electronic voting process takes longer than officials expected, which could result in long lines on election day.

Unauthorized distribution of software underscores the potential for security problems associated with the use of electronic voting systems, said Stamp.

"Perception among voters is key, because we know the lengths to which people might go to rig an election, for example, with a fully-automated process," he noted.

Bob Wilson, an official with the Illinois Ballot Integrity Project - which bills itself as a not-for-profit civic organization dedicated to the correction of election system deficiencies - tells ABC News that last week his organization hacked the database, which contains detailed information about hundreds of thousands of Chicago voters, including their Social Security numbers, and dates of birth.

"It was a serious identity theft problem, but also a problem that could potentially create problems with the election," Wilson said.

A nefarious hacker could have changed every voter's status from active to inactive, which would have prevented them from voting, he said.

"Or we could've changed the information on what precinct you were in or what polling place you were supposed to go to," he said. "So there were ways that we could potentially change the entire online data base and disenfranchise voters throughout the entire city of Chicago."

"If we'd wanted to, we could've wiped the entire database out," Wilson claimed.

Tom Leach, a spokesman for the Chicago Election Board, tells ABC News that the problem seems to have arisen because the city's database allowing voters to locate their voting precinct once asked voters for detailed information such as Social Security numbers.

Approximately six years ago, Leach said, when the website was updated - requiring only name and address - city computer experts "never cut the links to the Social Security numbers and the dates of birth."

Leach said he doubted the Illinois Ballot Integrity Project could have disenfranchised voters or wiped out the database, but he and the Election Board were very concerned and had taken steps to remedy whatever problems exist, including bringing in an outside computer forensic expert to verify that the database is secure and to ensure no one had already hacked the database.

"We're also making arrangements to remove the Social Security numbers," he added, and the Election Board was also alerting law enforcement to the problem as pointed out to them.

"Even though they could hack into the Web site, they couldn't hack into the voter file," Leach said. "The Web site feeds into a copy file, not the actual original file."

Leach said the issue had absolutely nothing to do with the city's electronic voting machines, which are manufactured by Sequoia Voting Systems.

But Wilson counters that this is just one hole in a system that may be full of them.

"This is a part of the entire electronic voting program that we're depending on - computerized voter databases and electronic voting machines," Wilson said. "Any computer is subject to failure and security flaws and we have seen in electronic voting hundreds of news reports about dozens and dozens of jurisdictions where there are problems."

"You constantly distort and, frankly, just tell lies," Lieberman, who ran as an independent after losing the Democratic primary to Lamont, said at the Garde Arts Center New London. "No matter how many millions of his own family's money Ned Lamont spends, the polls show the people of Connecticut are not buying it. They can't be bought."

Lamont, a wealthy cable TV executive who has poured $12.7 million of his own fortune into his campaign, bristled.

"Senator Lieberman just called me a liar and he made a lot of outrageous accusations," Lamont replied. "Senator, everything we're talking about is your record, and you can't run from your record."

Hecklers interrupted the debate at times, and some chanted "Lieberman Protects Cheney." They were escorted from the theater.

An exasperated Lieberman, a particular target for outbursts from the audience, scolded the hecklers. "C'mon," he said, "let's let the candidates talk."

Lieberman's support for the war in Iraq drew criticism from Lamont and Republican candidate Alan Schlesinger.

"Joe Lieberman and George Bush's stay-the-course strategy, that's the recipe for failure," Lamont said.

Lieberman warned that Lamont's support for a deadline for U.S. troop withdrawals would be disastrous.

"Your answer is to give up on Iraq," Lieberman said. "Your plan is a recipe for retreat and disaster."

Lamont's primary upset of Lieberman last August was fueled primarily by his strong anti-war views. Lieberman reiterated Monday night that if re-elected he would still caucus with the Democrats.

"Not only am I a man of my word, it's what I want to do," Lieberman said.

Schlesinger has tried to use the debates to climb out of the single digits in the polls. Lieberman and Schlesinger are vying for Republican support, so any Schlesinger gains could come at Lieberman's expense.

Schlesinger accused Lieberman of trying to mask his liberal record to win GOP votes.

"In the spirit of Halloween, we have a U.S. senator here who's masquerading as a Republican," said Schlesinger, the former mayor of Derby.

Schlesinger also chided Lieberman on health care, accusing him of avoiding the truth about how the massive generation of baby boomers needing health care in coming years will overwhelm the nation's medical system.

"For 18 years, our senator has not been straight with you," Schlesinger said.