Election officials say electronic voting machines have been tested for security and accuracy, despite critics' accusations that the computers can be hacked and results rigged.
"We have an extraordinary level of confidence," said Mike Morrill, spokesman for Diebold Election Systems, which manufacturers the touch-screen voting machines used throughout Maryland. "They've proven accurate and reliable, and that's exactly what we expect in this November's election across the country."
Howard T. Van Pelt, president and chief executive officer of Advanced Voting Solutions Inc., likewise said the voting machines it supplied to Fairfax and Arlington counties and nearly three dozen other Virginia jurisdictions have passed all pre-election tests.
"The equipment has all been checked and is all ready to go," Mr. Van Pelt said.
The 2004 elections were plagued by reports of malfunctioning machines or votes cast for the wrong candidate. During Maryland's Sept. 12 primaries, machines in Montgomery County could not be operated because poll workers forgot to bring ballot cards.
"Some people blame problems on electronic voting when it's really not. It's just human error," said David Orr, a Democrat and clerk of Cook County, Ill., who conducts elections in Chicago's suburbs. "Any honest election person will tell you mistakes happen."
Beverly Kaufman, chairman of the Election Administration Board of the National Association of County Recorders, Election Officials and Clerks -- the organization of elected officials who conduct U.S. elections -- said federal law requires that security systems be built into the machines.
"There are perceived problems. But if there's a problem, it's not a machine problem; it's a human problem," said Mrs. Kaufman, a Republican and Harris County clerk in Houston.
Elections will be held in more than 3,000 counties using various types of voting machines. Most widely used are the touch screens, which resemble automated teller machines, and the optical-scan devices, which read and tabulate paper ballots.
The four companies that make the majority of machines used in U.S. elections are Diebold, Sequoia Voting Systems, Election Systems & Software, and Hart InterCivic.
Diebold, the largest, has 40 percent of the market with 150,000 machines in 37 states. Critics have charged that Diebold can manipulate the vote count and that the machines are susceptible to hacking.
HBO last night aired a documentary, "Hacking Democracy," that accused Diebold of subtracting 16,000 votes from Democrat Al Gore on one Florida voting machine in the 2000 presidential election.
Diebold officials said their company did not have any share of the election industry until 2002, the year Diebold bought Global Election System. GES did not manufacture the machine depicted in the HBO program, a spokesman said.
"The first of these material errors is the statement that Diebold tabulated more than 40 percent of the votes cast in the 2000 presidential election," Diebold President David Byrd wrote in an Oct. 30 letter to Chris Albrecht, HBO's president.
Avi Rubin, a Johns Hopkins University professor with a doctorate degree in computer science, published a 2003 study showing how a computer virus could alter results of electronic voting.
"I think the big issue is the fact that you can't really tell if the machine got the right answer," Mr. Rubin said.
Election officials said such studies do not account for security precautions in actual voting places.
"If I give you the keys to my car, you can steal it pretty easily and that's what's going on in these laboratories," said Jean Jensen, secretary of the Virginia Board of Elections. But if my car is locked in my garage and my keys are locked in my house, which has an alarm and an 80-pound black Labrador retriever, you're going to have a lot more trouble stealing my car."
Mr. Morill said critics are asking the impossible.
"There has never been one election where a machine was hacked, but they want us to prove it hasn't happened," the Diebold spokesman said.