An estimated 40 million Americans cast votes last week on approximately 175,000 touch-screen voting machines, also known as direct-recording electronic, or DRE, voting systems. While fears of widespread problems with the systems didn't come to pass, scattered problems did occur and at least one county suffered a major glitch. Don't expect the controversy surrounding DRE systems to end anytime soon.

Following the 2000 presidential election, Congress passed the Help America Vote Act of 2002, which allocated $3.6 billion for improving election administration and updating antiquated paper-based voting systems.

Many states quickly invested in touch-screen systems. Too quickly, some say, and without safeguards such as "voter-verified paper-trail" technology that lets voters validate that votes on the screen match a paper printout. In the event of a recount, election officials also could use the printouts and not rely solely on machine tallies.

The touch-screen systems weren't perfect last week. More than 4,500 votes were lost in Carteret County, N.C., when more votes were cast than the electronic voting systems could store. The incident is being investigated by the North Carolina State Board of Elections.

The election incident-tracking Web site voteprotect.org, operated by election-watch groups, said 1,222 voting-machine-related incidents were reported through Wednesday afternoon. Not all of those involved DRE systems. But in Florida's Broward and Miami-Dade counties, there were scattered reports that system-checkout screens switched the candidates voters had selected.

In Nevada, the only state with a large number of electronic-voting systems with voter-verified paper-trail capabilities, only a handful of problems were reported. Many states, including California and Ohio, have mandated that DRE systems be equipped with paper-trail capabilities in future elections.

Backers of touch-screen voting systems say they enhance the election process by providing more-precise vote tallies than manual counts, enabling disabled and non-English-speaking voters to cast ballots more easily, and eliminating "overvoting," when a voter selects two candidates for the same office.

Electronic voting machines used around the country were manufactured by Diebold Election Systems, Election Systems & Software, Hart InterCivic, and Sequoia Voting Systems.

"Overall, electronic voting went well," says Doug Chapin, director of the Election Reform Information Project, a nonpartisan research group. "I think because the discussion now is about why [John] Kerry lost and [President] Bush won, and not about the election process itself, means it was generally a success. It's a positive thing that people are looking for problems and documenting issues. It will only make the systems better."

Avi Rubin, computer science professor and technical director of the Information Security Institute at Johns Hopkins University, isn't comforted by Tuesday's results. Rubin co-authored a 2003 report about the security of the software used in many Diebold voting systems. "In a voter-verified paper-trail system, the North Carolina problem couldn't have occurred," he says. "If the electronic votes were lost due to a computer malfunction, the paper votes would still be there and could be counted."