WASHINGTON -- Congressional Democrats hope to move quickly on legislation that would make obsolete many touch-screen voting machines, including those in use across Pennsylvania.

Rep. Rush Holt, D-N.J., this week introduced a bill that requires machines to have paper trails that allow voters to verify their choices. Sen. Dianne Feinstein, D-Calif., plans to bring a similar bill before the Senate.

Both lawmakers want to put the new standard in place before the 2008 presidential election.

"I think we should try. Whether we can get there or not remains to be seen," Ms. Feinstein, who chairs the Senate Committee on Rules and Administration, said yesterday after a hearing on problems with electronic voting. "There needs to be some national standard."

Momentum for such a move has been building nationwide. In Florida, home of the infamous "hanging chads" of the 2000 election that prompted widespread changes in voting technology, Gov. Charlie Christ announced last week that the state would dispose of expensive touch-screen machines in favor of paper ballots read by optical scanners. The Virginia Senate also passed a bill that would gradually replace touch-screen units with the scanners.

Florida's most recent voting woes were at the center of yesterday's committee hearing. Uncertainty still hangs over November election results in the state's 13th Congressional District, where Republican Vern Buchanan bested Democrat Christine Jennings by 369 votes.

Ms. Jennings has sued, pointing to Sarasota County's 18,000 "undervotes," or the number of voters who made no choice for their ballot's congressional contest. Neighboring counties recorded much fewer undervotes.

So far, a judge has not allowed the Jennings campaign to bring in its own experts for an examination of the copyright-protected software in the ES&S iVotronic voting machine. Florida officials have already conducted a review, said ES&S spokesman Ken Fields.

The Nebraska company is the most popular vendor in Western Pennsylvania. Allegheny, Beaver, Butler, Cambria, Greene and Westmoreland counties all have purchased the firm's iVotronic machines.

Last year, Allegheny County used primarily federal money to award an $11.9 million contract for more than 4,600 touch-screen machines. The county also negotiated a $3 million option to add a paper-trail system to those machines, but that option most likely would not meet the standard of the proposed federal change.

New Jersey's Mr. Holt called the Florida situation "Exhibit A" in his push for mandatory paper trails. "A Democratic government works only if we believe it does," he said. "And the confidence in the mechanism of our government has been shaken badly."

His bill would make the paper trail the "vote of record," and it would require random audits to ensure that machines are properly compiling votes. It also would provide $300 million to help states and local governments pay for new equipment.

That figure, however, is dwarfed by the $3 billion in federal money doled out under the Help America Vote Act, or HAVA, the law passed in the wake of Florida's 2000 presidential debacle. The expense for more equipment, or upgrades to earlier purchases, would be considerable, and local governments would face another daunting transition just a few years after their first purchases of new technology.

"Obviously, if something were passed at the federal level, we'd have to accomplish it in whatever timeline was given," Pennsylvania Department of State spokeswoman Cathy Ennis said.

Several election officials yesterday urged senators to be wary of making hasty modifications to HAVA.

"Please remember that any additional change prior to the 2008 presidential election is likely to place an additional burden on the already very stressed system," said Connie Schmidt, president of Election Consulting Services.

She also said her organization has found that voters make fewer mistakes with touch-screen machines than with optical-scan ballots, which resemble standardized tests and can have stray marks that confuse scanning equipment.

Yet proponents of Mr. Holt's bill argue that a paper trail is a needed backup in cases of close elections in which a machine malfunction or fraud is suspected.

"The important thing here is not that there's a foolproof system, but that an auditable record enables you to check," said Michael Waldman, executive director of the Brennan Center for Justice at the New York University School of Law.

Mr. Holt's bill has encouraged a grass-roots movement of voting-rights activists that has long advocated for use of optical scanners in Pennsylvania.