The legislation, which the California Democrat and Rep. Rush Holt, D-N.J., plan to introduce early next year, also would require electronic voting companies to meet tougher security standards, including background checks for software engineers.
"I'm not a paranoid person by nature in any way, but we need to make sure there's confidence built into the system," Boxer said Thursday in a phone interview. "I can think of nothing more important than to be sure that every vote counts."
Voting rights advocates and computer scientists have argued that paperless voting machines such as touchscreen terminals expose elections to hackers, software bugs and mechanical failures. But voting equipment companies and county registrars say requiring paper records would dramatically increase the cost and complexity of voting.
Last month, California's secretary of state announced that all electronic voting machines in the state must provide paper receipts by 2006.
Boxer's bill would provide emergency funding for counties across the country to accommodate printers, expected to cost at least $500 per machine.
Counties nationwide are rushing to modernize voting equipment to qualify for $3.9 billion in federal matching funds as part of the 2002 Help America Vote Act (search).
Electronic ballots, which some experts say will account for 75 percent of U.S. voting by 2010, have been lauded as more accurate alternatives to lower-tech methods such as the punchcard ballots criticized after the 2000 presidential election.
Voting companies immediately promised to comply with the bill if it becomes law, but executives characterized the deadline as unrealistic. None of the nation's largest voting equipment vendors sells printers that have passed federal certification.
Oakland-based Sequoia Voting Systems (search) plans to submit a printer for certification in the first quarter of 2004, but the certification process probably will take several months.
"We certainly wouldn't be able to provide this to every voting jurisdiction across the country by 2004," Sequoia spokesman Alfie Charles said.
Mischelle Townsend, registrar of voters for Riverside County, called the idea of requiring paper receipts "totally unreasonable."
Adding printers to the California county's 4,250 machines would cost at least $2 million, she said, and the printing would cost another $600,000 per year.
"For a legislator to irresponsibly mandate extraordinary costs in California, which is in the worst fiscal crisis in its history, is outrageous," Townsend said.
But Kim Alexander, president of the California Voter Foundation (search), said paper records would give voters peace of mind.
"I'd be thrilled to see a voter-verified paper trail come online by the 2004 election," Alexander said.